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Odontoma of the Middle Ear

Odontoma of the Middle Ear We report the 25-year follow-up on the first reported case of odontoma in the middle ear. Diagnosis of odontoma had been made on the basis of radiography films that showed a middle ear mass with multiple toothlike areas of radiopacity. No clinical intervention was recommended. At 25-year follow-up, audiometry showed progressive mixed hearing loss on the affected side and mild ipsilateral sensorineural hearing loss. Computed tomography better characterized the discrete mass, which was shaped similar to a dental crown. To avoid jeopardizing cochlear and facial nerve function, no surgical intervention was pursued, and we recommended use of a BiCROS (bilateral contralateral routing of signal) hearing aid.REPORT OF A CASEA 32-year-old man was seen for long-standing hearing loss that was profound in the right ear and mild in the left ear. He denied having otalgia, tinnitus, or vertigo, or a history of ear infection, excessive noise exposure, exposure to ototoxins, or head trauma. The probable cause of hearing loss in the right ear—a bony mass presumed to be an odontoma in the middle ear—was established 25 years previously by conventional temporal bone radiography and polytomography.At that time, surgical treatment of his right ear was avoided so as not to jeopardize facial nerve function. When seen at our clinic, the patient expressed renewed interest in improving his hearing in the right ear.At the time of the patient's original evaluation, reported results of otoscopic examination showed a dull right tympanic membrane and audiometry showed severe conductive hearing loss on the right side.When we saw the patient 25 years later, results of otoscopic examination were normal, and audiometry showed mild sensorineural hearing loss in the left ear and severe to profound mixed hearing loss in the right ear. Speech discrimination was 100% for the left ear and 76% for the right ear.Reported results of conventional temporal bone radiography and polytomography showed a mass in the right middle ear cavity with multiple toothlike areas of radio-opacity. The mass occluded the oval window niche, covered the promontory of the tympanum, and extended into the hypotympanum; ossicles were not detected. At 25-year follow-up, the temporal bone was imaged with computed tomography (CT). The CT scan of the right ear showed hyperdensity on the middle ear surface of the promontory. The hyperdense area appeared as a wavy stripe less than 1 mm thick (Figure 1), which tapered and curved medially at both ends. The center of the stripe formed a cusp pointing toward the cranial cavity. The shape of the stripe resembled a backward numeral 3. Because of the different imaging modalities, we were unable to determine if the mass had changed in size or position in the 25 years since the initial images were taken.Coronal computed tomographic scan of right temporal bone shows otic odontoma. Arrow indicates hyperdense area appearing as a wavy stripe less than 1 mm thick, which resembles a backward numeral 3. The stripe tapers and curves medially at both ends, and the center of the stripe forms a cusp pointing toward the cranial cavity.Possible diagnoses of such bright hyperdensity in the middle ear include osteoma, tympanosclerosis, or odontoma. However, osteoma usually occurs in the external ear canal and appears on x-ray films or CT scans as a bony, hyperdense, roughly spherical mass. Furthermore, osteoma causes pure conductive hearing loss in contrast to that our patient experienced. The hyperdensity of tympanosclerosis within the middle ear usually appears as a thin, calcified stripe outlining the middle ear cavity, not the thick lines of an apparently discrete mass as seen in this case. Furthermore, tympanosclerosis is usually seen in patients with chronic otitis media, which our patient did not have. Otic odontoma was diagnosed.COMMENTOdontoma is an odontogenic tumor that consists of multiple tissue types and is therefore usually referred to as composite odontoma. Odontoma is a generally benign neoplasm derived from functional ameloblasts and odontoblasts that form an abnormal pattern of enamel and dentin.The enamel and dentin most commonly form compound composite odontomastructures, which resemble normal teeth; however, in some odontomas, the enamel and dentin instead form a complex composite odontoma,a disorganized calcified mass with no morphologic similarity to teeth.Odontoma is usually painless but prevents normal tooth eruption in almost half of cases.Most diagnoses of odontoma are made in patients younger than 30 years and odontoma most commonly occurs in the anterior maxilla but may occur anywhere in the maxillary or mandibular tooth-bearing bone; extragnathic odontoma is rare. To our knowledge, the article describing the original evaluation of this patient represented the first reported case of odontoma in a human middle ear,and we know of no subsequent case reports of otic odontoma in a human.Odontoma is thought to arise from an embryologic mishap.The middle ear cleft is derived from the first pharyngeal pouch.During the third week of gestation, the first and second pharyngeal pouches lie laterally on either side of the future oral and pharyngeal tongue.As the third arch enlarges, the first pharyngeal pouch space between the second arch and pharynx is compressed and becomes the eustachian tube.The middle ear space is formed from a lateral outpouching of the eustachian tube.During middle ear cleft development, ectopic dental anlage cells are probably transported into the middle ear, where the cells develop into the rudimentary tooth forms shown on the CT scan. Mandibular and maxillary odontomas do not grow larger after they calcify; therefore, we would not expect this patient's middle ear odontoma to enlarge.Mandibular and maxillary odontomas are unlikely to recur after they have been enucleated.Though enucleation was an option for this patient, the potential improvement in the conductive hearing loss of the right ear would not justify the risk of sensorineural hearing loss and facial nerve injury. No biopsy was performed because, clinically, we believed that any surgery would not have improved the patient's primary complaint of hearing loss. In fact, surgical intervention could have worsened the patient's hearing or caused a facial nerve injury. Currently, we recommend a BiCROS (bilateral contralateral routing of signal) hearing aid to rehabilitate this patient's hearing.RJBellucciJZizmorREGoodwinOdontoma of the middle ear: a case presentation.Arch Otolaryngol.1975;101:571-573.http://www.ncbi.nlm.nih.gov/htbin-post/Entrez/query?db=m&form=6&Dopt=r&uid=entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=1164242&dopt=AbstractPELarsenAKHegtvedtOdontogenesis and odontogenic cysts and tumors.In: Cummings CW, Fredrickson JM, Harker LA, Krause CJ, Schuller DE, Richardson MA, eds. Otolaryngology Head & Neck Surgery.3rd ed. St Louis, Mo: Mosby; 1998:1572-1601.WHArcherOral and Maxillofacial Surgery.5th ed. Philadelphia, Pa: WB Saunders; 1975.GEKaugarsMEMillerLMAbbeyOdontomas.Oral Surg Oral Med Oral Pathol.1989;67:172-176.http://www.ncbi.nlm.nih.gov/htbin-post/Entrez/query?db=m&form=6&Dopt=r&uid=entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=2919061&dopt=AbstractEJDierksMLBernsteinOdontogenic cysts, tumors, and related jaw lesions.In: Bailey BJ, Johnson JT, Kohut RI, Pillsbury HC III, Tardy ME Jr, eds. Head and Neck Surgery–Otolaryngology.Philadelphia, Pa: JB Lippincott; 1993:1176-1191.SDBudnickCompound and complex odontomas.Oral Surg Oral Med Oral Pathol.1976;42:501-506.http://www.ncbi.nlm.nih.gov/htbin-post/Entrez/query?db=m&form=6&Dopt=r&uid=entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=1067549&dopt=AbstractKJLeeAnatomy of the ear.In: Lee KJ, ed. Essential Otolaryngology: Head & Neck Surgery.6th ed. Norwalk, Conn: Appleton & Lange; 1995:1-24.Clinical Notes: Odontoma of the Middle EarRichard J. Bellucci, MD;Judah Zizmor, MD;Richard E. Goodwin, MDFrom the Department of Otolaryngology, New York Medical College (Dr. Bellucci), and the departments of Otolaryngology (Drs. Bellucci and Goodwin) and Radiology (Dr. Zizmor), Manhattan Eye, Ear, and Throat Hospital, New York.Arch Otolaryngol. 1975; 101:571-573AbstractWe report a case of an odontoma of the middle ear cavity. A brief description of odontomas and their development is given with an embryologic account of middle ear cleft development. The developmental relationships of a nasopharyngeal odontoma, an odontogenic craniopharyngioma and an otic odontoma are presented.A 7½-year-old boy had an odontoma in the middle ear cavity and a unilateral conductive hearing loss. Extensive review of the medical literature failed to uncover any previous report of an otic odontoma. Reports of extragnathic odontomas are rare, although the literature has many reports of odontomas in tooth-bearing areas.REPORT OF A CASEThe patient was admitted to Manhattan Eye, Ear, and Throat Hospital on July 17, 1974, with recently discovered loss of hearing in the right ear. He had a history of occasional pain in the right ear, associated with acute upper-respiratory tract infections, that subsided as a result of treatment without developing otorrhea.The patient is the firstborn child of a woman with thalassemia minor (Mediterranean anemia) that was undetected until her third month of pregnancy, when she became symptomatic as a result of this severe anemia. She was treated with folate sodium, ferrous sulfate and “iron injections.” The father has no history of pertinent disease, but the patient's 6-year-old sister also has thalassemia minor. The maternal grandfather has the trait for thalassemia minor. A dental examination during the week prior to admission revealed that the patient had a missing lower bicuspid tooth on the left side of his mouth.Physical examination revealed a dull right tympanic membrane of whitish color with no landmarks. The left tympanic membrane appeared normal. Dentition was normally developed for a 7½-year-old boy. The tonsils and adenoids were hypertrophic, chronically infected, and associated with anterior cervical lymphadenopathy. Audiometry revealed a conductive hearing loss on the right side (Figure 1). Results of the remainder of the physical examination were normal.Fig 1.—Audiogram showing a right sided conductive hearing loss.On admission, an adenotonsillectomy was performed and a diagnostic exploratory tympanotomy was done on the right ear. An unusually hard immobile object was firmly palpated under the tympanic membrane. No fluid was obtained and no middle ear space could be found on palpation of all quadrants of the tympanic membrane.Conventional temporal bone radiography and polytomography (Figure 2, Figure 3, Figure 4, Figure 5, Figure 6, Figure 7, and Figure 8) revealed normal left inner and middle ear development. A dental mass, apparently an odontoma, with two well-formed dental crowns and several denticles, occupied the medial half of the right middle ear cavity. The dental mass occluded the oval window niche, covered the promontory of the tympanum, and extended down into the hypotympanum. Ossicles were not detectable in the attic or tympanic cavity. Cochlear and vestibular structures were normally developed and the lateral middle ear cavity and mastoid cells were aerated. The attic spur was intact and the attic was not enlarged.Fig 2.—Left, Schuller view of right side showing cluster of teeth (black arrows). Right, Normal Schuller view of left side.Fig 3.—Left, Owens view showing dental mass in middle ear (arrows). Right, normal Owens view of left side.Fig 4.—Occipital view showing cluster of denticles in medial aspect of middle ear cavity (arrows).Fig 5.—Anteroposterior coronal tomogram showing a 1-mm section through anterior middle ear cavity and cochlea showing mass against promontory extending into hypotympanum (arrows).Fig 6.—Anteroposterior coronal tomogram in plane of vestibule and internal auditory canal. Note dental mass in medial half of middle ear cavity occluding oval window (black arrow) and extending downward into hypotympanum (white arrows).Fig 7.—Lateral tomogram through medial half of middle ear cavity showing that dental mass almost fills medial half of tympanic cavity (arrows).Fig 8.—Lateral tomogram showing dental mass filling medial tympanic cavity (arrows).Since the patient had normal hearing in the left ear, the decision was made to avoid surgical intervention that might jeopardize the cochlear and facial nerve functions.ODONTOMAThe word odontoma was coined from the Greek in 1869 by Broca, and means “tooth tumor.”1Odontomas are now recognized as benign neoplasms composed of dental elements such as enamel, dentine, pulp, and cementum.2,3The compound odontoma is the most frequently occurring type.4The compound odontoma reveals itself radiographically as a mass containing denticles and one or more well-formed dental crowns.3,4,5The dental crowns are often dwarfed, distorted, and without roots. These dental masses are frequently surrounded by a fibrous membrane that may attach to bone like a normal tooth's periodontal membrane.4Complex odontomas contain multiple bizarre formations of radiopaque tooth forms.4Cystic odontomas are formed when a cyst filled with fluid is present in association with the dental mass.2Clinically, patients with odontomas present with a painless slow-growing mass that can be associated with the absence of a nearby permanent tooth in the upper or lower jaws.2,6They are usually, but not always, detected before adulthood. There is a greater incidence of odontomas in the posterior mandibular region than elsewhere in the jaws, and the clinical findings depend on the size and location of the mass.2Radiography is the most reliable means of diagnosis.Odontomas are true developmental disturbances of the tooth germ.2,5They are derived from both embryonic ectoderm and mesoderm.5,6The fact that they develop in early life, before completion of the second dentition, indicates their relationship to an embryologic abnormality.2Embryology of OdontomaAt the sixth to seventh week of gestation, the embryo in man develops arcs of thickened tissue within the primitive mouth opening—the dental laminae.7,8These arcs in each jaw then sink into the subjacent mesenchyme and, simultaneously, the adjacent labiogingival laminae appear as grooves separating the future lips from the future gums. Laterally, wedges of mesenchyme remain and project outward to become the villous or labial part of the gums. The medial wedge of mesenchyme becomes the smooth lingual gum.9By the tenth week, the labiogingival grooves deepen to separate the cheeks and lips and the vestibule of the mouth from the gums. At three months, the submerged dental laminae produce a series of upper and lower buds, ie, enamel organs. These ameloblasts (enamel-producing cells) surround mesenchymal dental papillae.8Hence the teeth arise within the gum, deriving enamel from the epithelium, and can derive dentine and roots from mesenchyme. Side branches off these enamel organs form new small enamel buds from which the permanent dentition will later arise. The interconnections for these buds disrupt and disappear by the fifth month of gestation and the stalks of these buds are absorbed. Dentine is deposited in the crown, the neck, and finally, in the roots.8Should the interconnections of the enamel organs persist they could develop into a cyst or odontogenic tumor.8Middle Ear Cleft DevelopmentThe auditory tube develops from the first pharyngeal pouch entoderm that extends outward in the mesoderm toward the first ectodermal branchial groove.7,9,10The auditory ossicles are derived from the first and second cartilaginous branchial arches. By the ninth week, the primitive auditory tube begins to invest the auditory ossicles. At this stage, the external ear is represented only by a superficial elevation anterior to the branchial groove. The internal ear, which is of ectodermal origin, is represented by the endolymphatic duct system lodged in the adjacent mesenchyme. It differentiates from a primitive otocyst and the perilymphatic labyrinth forms by progressive vacuolization. It is later invested by cartilage. The growth and differentiation here is so rapid that by the 23rd week of gestation the cochlea attains its adult dimensions and the periotic spaces are well formed.9COMMENTIn 1946, McClure reported a nasopharyngeal odontoma.1This only recorded case of an extragnathic odontoma was a true choristoma. He reviewed a large series of nasopharyngeal tumors and found no mention of an odontoma. Odontogenic craniopharyngioma is also reported to occur and perhaps an embryologic relationship can be inferred.10Embryology explains the possible mechanism of the occurrence of middle ear odontoma, nasopharyngeal odontoma, and odontogenic craniopharyngioma. At some stage of differentiation, dental anlage cells may migrate caudad within the foregut lumen to the primordium of the nasopharynx or rostral to the Rathke pouch. This may possibly occur at the third week of gestation, when the buccopharyngeal membrane ruptures and connects the stomodeum to the foregut.11Ectodermal cells that are to form the dental laminae come to rest against the entoderm in the region of the first pharyngeal pouch or at the Rathke pouch. Another alternative is the de novo appearance of ameloblasts in the first branchial arch or area of the Rathke pouch.The Eustachian tube that develops as a lateral outpouching of the first pharyngeal pouch forms the middle ear cleft. In the process, this tube may carry ectopic primordial dental anlage cells to the developing middle ear cavity, where dental development would then occur with formation of a dental mass. If this were to happen, the tooth forms would be within the middle ear's mucosa-lined cavity. However, the dental masses would be mucosa covered if pushed to the region by an entodermal outgrowth. Odontogenic cells located adjacent to the primordial first pharyngeal pouch area could develop as a nasopharyngeal odontoma. Alternatively, if the odontogenic cells were lying in the primordial Rathke pouch, they could be carried toward the developing site of the hypophysis and develop into an odontogenic craniopharyngioma.ReferencesMcClure G. Odontoma of the nasopharynx. Arch Otolaryngol.1946;44:51-60.Gorlin RJ, Goldman HM. Thoma's Oral Pathology. St. Louis, CV Mosby Co, 1970, vol 1, pp 497-501.Robbins SL. Pathology. Philadelphia, WB Saunders Co, 1967, vol 2, chap 20, pp 770-817.Zegarelli EV, Dutscher AH, Hyman GA. Diagnosis of Disease of the Mouth and Jaws. Philadelphia, Lea & Febiger Publishers, 51969, pp 214-217.Shanks SC, Kerley P. A Text-Book of X-Ray Diagnosis, ed 4. Philadelphia, WB Saunders Co, 1969, vol 1, chap 19, pp 517-519.Gorlin RJ, Meskin LH, Brodey R. Odontogenic tumors in man and animals: Pathologic classification and clinical behavior: A review. Ann NY Acad Sci. 1963;108:722-771.Langman J. Medical Embryology. Baltimore, Williams & Wilkins Co, 1963, pp 197-211, 293-302, 316-318.Ward GE, Hendrick JW. Tumors of the Head and Neck. Baltimore, Williams & Wilkins Co, 1957, pp 44-49, 341-344.Papparella MM, Shumrick DA. Otolaryngology. Philadelphia, WB Saunders Co, 1973, vol 1, chap 1, pp 3-74.Kalnins V, Rossi E. Odontogenic craniopharyngioma. Cancer. 1965;19:899-906.Arey LB. Developmental Anatomy, ed 7. Philadelphia, WB Saunders Co, 1965, pp 541-550.Submitted for publication February 17, 2003; final revision received April 30, 2004; accepted May 14, 2004.The Kaiser Permanente Community Benefit Program provided research support.The Kaiser Foundation Hospitals, Inc, Medical Editing Department provided editorial assistance.Correspondence: Barry Rasgon, MD, Department of Head and Neck Surgery, Kaiser Permanente Medical Center, 280 W MacArthur Blvd, Oakland, CA 94611 (barry.rasgon@kp.org). http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png JAMA Otolaryngology - Head & Neck Surgery American Medical Association

Odontoma of the Middle Ear

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American Medical Association
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Copyright 2004 American Medical Association. All Rights Reserved. Applicable FARS/DFARS Restrictions Apply to Government Use.
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2168-6181
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10.1001/archotol.130.10.1223
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Abstract

We report the 25-year follow-up on the first reported case of odontoma in the middle ear. Diagnosis of odontoma had been made on the basis of radiography films that showed a middle ear mass with multiple toothlike areas of radiopacity. No clinical intervention was recommended. At 25-year follow-up, audiometry showed progressive mixed hearing loss on the affected side and mild ipsilateral sensorineural hearing loss. Computed tomography better characterized the discrete mass, which was shaped similar to a dental crown. To avoid jeopardizing cochlear and facial nerve function, no surgical intervention was pursued, and we recommended use of a BiCROS (bilateral contralateral routing of signal) hearing aid.REPORT OF A CASEA 32-year-old man was seen for long-standing hearing loss that was profound in the right ear and mild in the left ear. He denied having otalgia, tinnitus, or vertigo, or a history of ear infection, excessive noise exposure, exposure to ototoxins, or head trauma. The probable cause of hearing loss in the right ear—a bony mass presumed to be an odontoma in the middle ear—was established 25 years previously by conventional temporal bone radiography and polytomography.At that time, surgical treatment of his right ear was avoided so as not to jeopardize facial nerve function. When seen at our clinic, the patient expressed renewed interest in improving his hearing in the right ear.At the time of the patient's original evaluation, reported results of otoscopic examination showed a dull right tympanic membrane and audiometry showed severe conductive hearing loss on the right side.When we saw the patient 25 years later, results of otoscopic examination were normal, and audiometry showed mild sensorineural hearing loss in the left ear and severe to profound mixed hearing loss in the right ear. Speech discrimination was 100% for the left ear and 76% for the right ear.Reported results of conventional temporal bone radiography and polytomography showed a mass in the right middle ear cavity with multiple toothlike areas of radio-opacity. The mass occluded the oval window niche, covered the promontory of the tympanum, and extended into the hypotympanum; ossicles were not detected. At 25-year follow-up, the temporal bone was imaged with computed tomography (CT). The CT scan of the right ear showed hyperdensity on the middle ear surface of the promontory. The hyperdense area appeared as a wavy stripe less than 1 mm thick (Figure 1), which tapered and curved medially at both ends. The center of the stripe formed a cusp pointing toward the cranial cavity. The shape of the stripe resembled a backward numeral 3. Because of the different imaging modalities, we were unable to determine if the mass had changed in size or position in the 25 years since the initial images were taken.Coronal computed tomographic scan of right temporal bone shows otic odontoma. Arrow indicates hyperdense area appearing as a wavy stripe less than 1 mm thick, which resembles a backward numeral 3. The stripe tapers and curves medially at both ends, and the center of the stripe forms a cusp pointing toward the cranial cavity.Possible diagnoses of such bright hyperdensity in the middle ear include osteoma, tympanosclerosis, or odontoma. However, osteoma usually occurs in the external ear canal and appears on x-ray films or CT scans as a bony, hyperdense, roughly spherical mass. Furthermore, osteoma causes pure conductive hearing loss in contrast to that our patient experienced. The hyperdensity of tympanosclerosis within the middle ear usually appears as a thin, calcified stripe outlining the middle ear cavity, not the thick lines of an apparently discrete mass as seen in this case. Furthermore, tympanosclerosis is usually seen in patients with chronic otitis media, which our patient did not have. Otic odontoma was diagnosed.COMMENTOdontoma is an odontogenic tumor that consists of multiple tissue types and is therefore usually referred to as composite odontoma. Odontoma is a generally benign neoplasm derived from functional ameloblasts and odontoblasts that form an abnormal pattern of enamel and dentin.The enamel and dentin most commonly form compound composite odontomastructures, which resemble normal teeth; however, in some odontomas, the enamel and dentin instead form a complex composite odontoma,a disorganized calcified mass with no morphologic similarity to teeth.Odontoma is usually painless but prevents normal tooth eruption in almost half of cases.Most diagnoses of odontoma are made in patients younger than 30 years and odontoma most commonly occurs in the anterior maxilla but may occur anywhere in the maxillary or mandibular tooth-bearing bone; extragnathic odontoma is rare. To our knowledge, the article describing the original evaluation of this patient represented the first reported case of odontoma in a human middle ear,and we know of no subsequent case reports of otic odontoma in a human.Odontoma is thought to arise from an embryologic mishap.The middle ear cleft is derived from the first pharyngeal pouch.During the third week of gestation, the first and second pharyngeal pouches lie laterally on either side of the future oral and pharyngeal tongue.As the third arch enlarges, the first pharyngeal pouch space between the second arch and pharynx is compressed and becomes the eustachian tube.The middle ear space is formed from a lateral outpouching of the eustachian tube.During middle ear cleft development, ectopic dental anlage cells are probably transported into the middle ear, where the cells develop into the rudimentary tooth forms shown on the CT scan. Mandibular and maxillary odontomas do not grow larger after they calcify; therefore, we would not expect this patient's middle ear odontoma to enlarge.Mandibular and maxillary odontomas are unlikely to recur after they have been enucleated.Though enucleation was an option for this patient, the potential improvement in the conductive hearing loss of the right ear would not justify the risk of sensorineural hearing loss and facial nerve injury. No biopsy was performed because, clinically, we believed that any surgery would not have improved the patient's primary complaint of hearing loss. In fact, surgical intervention could have worsened the patient's hearing or caused a facial nerve injury. Currently, we recommend a BiCROS (bilateral contralateral routing of signal) hearing aid to rehabilitate this patient's hearing.RJBellucciJZizmorREGoodwinOdontoma of the middle ear: a case presentation.Arch Otolaryngol.1975;101:571-573.http://www.ncbi.nlm.nih.gov/htbin-post/Entrez/query?db=m&form=6&Dopt=r&uid=entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=1164242&dopt=AbstractPELarsenAKHegtvedtOdontogenesis and odontogenic cysts and tumors.In: Cummings CW, Fredrickson JM, Harker LA, Krause CJ, Schuller DE, Richardson MA, eds. Otolaryngology Head & Neck Surgery.3rd ed. St Louis, Mo: Mosby; 1998:1572-1601.WHArcherOral and Maxillofacial Surgery.5th ed. Philadelphia, Pa: WB Saunders; 1975.GEKaugarsMEMillerLMAbbeyOdontomas.Oral Surg Oral Med Oral Pathol.1989;67:172-176.http://www.ncbi.nlm.nih.gov/htbin-post/Entrez/query?db=m&form=6&Dopt=r&uid=entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=2919061&dopt=AbstractEJDierksMLBernsteinOdontogenic cysts, tumors, and related jaw lesions.In: Bailey BJ, Johnson JT, Kohut RI, Pillsbury HC III, Tardy ME Jr, eds. Head and Neck Surgery–Otolaryngology.Philadelphia, Pa: JB Lippincott; 1993:1176-1191.SDBudnickCompound and complex odontomas.Oral Surg Oral Med Oral Pathol.1976;42:501-506.http://www.ncbi.nlm.nih.gov/htbin-post/Entrez/query?db=m&form=6&Dopt=r&uid=entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=1067549&dopt=AbstractKJLeeAnatomy of the ear.In: Lee KJ, ed. Essential Otolaryngology: Head & Neck Surgery.6th ed. Norwalk, Conn: Appleton & Lange; 1995:1-24.Clinical Notes: Odontoma of the Middle EarRichard J. Bellucci, MD;Judah Zizmor, MD;Richard E. Goodwin, MDFrom the Department of Otolaryngology, New York Medical College (Dr. Bellucci), and the departments of Otolaryngology (Drs. Bellucci and Goodwin) and Radiology (Dr. Zizmor), Manhattan Eye, Ear, and Throat Hospital, New York.Arch Otolaryngol. 1975; 101:571-573AbstractWe report a case of an odontoma of the middle ear cavity. A brief description of odontomas and their development is given with an embryologic account of middle ear cleft development. The developmental relationships of a nasopharyngeal odontoma, an odontogenic craniopharyngioma and an otic odontoma are presented.A 7½-year-old boy had an odontoma in the middle ear cavity and a unilateral conductive hearing loss. Extensive review of the medical literature failed to uncover any previous report of an otic odontoma. Reports of extragnathic odontomas are rare, although the literature has many reports of odontomas in tooth-bearing areas.REPORT OF A CASEThe patient was admitted to Manhattan Eye, Ear, and Throat Hospital on July 17, 1974, with recently discovered loss of hearing in the right ear. He had a history of occasional pain in the right ear, associated with acute upper-respiratory tract infections, that subsided as a result of treatment without developing otorrhea.The patient is the firstborn child of a woman with thalassemia minor (Mediterranean anemia) that was undetected until her third month of pregnancy, when she became symptomatic as a result of this severe anemia. She was treated with folate sodium, ferrous sulfate and “iron injections.” The father has no history of pertinent disease, but the patient's 6-year-old sister also has thalassemia minor. The maternal grandfather has the trait for thalassemia minor. A dental examination during the week prior to admission revealed that the patient had a missing lower bicuspid tooth on the left side of his mouth.Physical examination revealed a dull right tympanic membrane of whitish color with no landmarks. The left tympanic membrane appeared normal. Dentition was normally developed for a 7½-year-old boy. The tonsils and adenoids were hypertrophic, chronically infected, and associated with anterior cervical lymphadenopathy. Audiometry revealed a conductive hearing loss on the right side (Figure 1). Results of the remainder of the physical examination were normal.Fig 1.—Audiogram showing a right sided conductive hearing loss.On admission, an adenotonsillectomy was performed and a diagnostic exploratory tympanotomy was done on the right ear. An unusually hard immobile object was firmly palpated under the tympanic membrane. No fluid was obtained and no middle ear space could be found on palpation of all quadrants of the tympanic membrane.Conventional temporal bone radiography and polytomography (Figure 2, Figure 3, Figure 4, Figure 5, Figure 6, Figure 7, and Figure 8) revealed normal left inner and middle ear development. A dental mass, apparently an odontoma, with two well-formed dental crowns and several denticles, occupied the medial half of the right middle ear cavity. The dental mass occluded the oval window niche, covered the promontory of the tympanum, and extended down into the hypotympanum. Ossicles were not detectable in the attic or tympanic cavity. Cochlear and vestibular structures were normally developed and the lateral middle ear cavity and mastoid cells were aerated. The attic spur was intact and the attic was not enlarged.Fig 2.—Left, Schuller view of right side showing cluster of teeth (black arrows). Right, Normal Schuller view of left side.Fig 3.—Left, Owens view showing dental mass in middle ear (arrows). Right, normal Owens view of left side.Fig 4.—Occipital view showing cluster of denticles in medial aspect of middle ear cavity (arrows).Fig 5.—Anteroposterior coronal tomogram showing a 1-mm section through anterior middle ear cavity and cochlea showing mass against promontory extending into hypotympanum (arrows).Fig 6.—Anteroposterior coronal tomogram in plane of vestibule and internal auditory canal. Note dental mass in medial half of middle ear cavity occluding oval window (black arrow) and extending downward into hypotympanum (white arrows).Fig 7.—Lateral tomogram through medial half of middle ear cavity showing that dental mass almost fills medial half of tympanic cavity (arrows).Fig 8.—Lateral tomogram showing dental mass filling medial tympanic cavity (arrows).Since the patient had normal hearing in the left ear, the decision was made to avoid surgical intervention that might jeopardize the cochlear and facial nerve functions.ODONTOMAThe word odontoma was coined from the Greek in 1869 by Broca, and means “tooth tumor.”1Odontomas are now recognized as benign neoplasms composed of dental elements such as enamel, dentine, pulp, and cementum.2,3The compound odontoma is the most frequently occurring type.4The compound odontoma reveals itself radiographically as a mass containing denticles and one or more well-formed dental crowns.3,4,5The dental crowns are often dwarfed, distorted, and without roots. These dental masses are frequently surrounded by a fibrous membrane that may attach to bone like a normal tooth's periodontal membrane.4Complex odontomas contain multiple bizarre formations of radiopaque tooth forms.4Cystic odontomas are formed when a cyst filled with fluid is present in association with the dental mass.2Clinically, patients with odontomas present with a painless slow-growing mass that can be associated with the absence of a nearby permanent tooth in the upper or lower jaws.2,6They are usually, but not always, detected before adulthood. There is a greater incidence of odontomas in the posterior mandibular region than elsewhere in the jaws, and the clinical findings depend on the size and location of the mass.2Radiography is the most reliable means of diagnosis.Odontomas are true developmental disturbances of the tooth germ.2,5They are derived from both embryonic ectoderm and mesoderm.5,6The fact that they develop in early life, before completion of the second dentition, indicates their relationship to an embryologic abnormality.2Embryology of OdontomaAt the sixth to seventh week of gestation, the embryo in man develops arcs of thickened tissue within the primitive mouth opening—the dental laminae.7,8These arcs in each jaw then sink into the subjacent mesenchyme and, simultaneously, the adjacent labiogingival laminae appear as grooves separating the future lips from the future gums. Laterally, wedges of mesenchyme remain and project outward to become the villous or labial part of the gums. The medial wedge of mesenchyme becomes the smooth lingual gum.9By the tenth week, the labiogingival grooves deepen to separate the cheeks and lips and the vestibule of the mouth from the gums. At three months, the submerged dental laminae produce a series of upper and lower buds, ie, enamel organs. These ameloblasts (enamel-producing cells) surround mesenchymal dental papillae.8Hence the teeth arise within the gum, deriving enamel from the epithelium, and can derive dentine and roots from mesenchyme. Side branches off these enamel organs form new small enamel buds from which the permanent dentition will later arise. The interconnections for these buds disrupt and disappear by the fifth month of gestation and the stalks of these buds are absorbed. Dentine is deposited in the crown, the neck, and finally, in the roots.8Should the interconnections of the enamel organs persist they could develop into a cyst or odontogenic tumor.8Middle Ear Cleft DevelopmentThe auditory tube develops from the first pharyngeal pouch entoderm that extends outward in the mesoderm toward the first ectodermal branchial groove.7,9,10The auditory ossicles are derived from the first and second cartilaginous branchial arches. By the ninth week, the primitive auditory tube begins to invest the auditory ossicles. At this stage, the external ear is represented only by a superficial elevation anterior to the branchial groove. The internal ear, which is of ectodermal origin, is represented by the endolymphatic duct system lodged in the adjacent mesenchyme. It differentiates from a primitive otocyst and the perilymphatic labyrinth forms by progressive vacuolization. It is later invested by cartilage. The growth and differentiation here is so rapid that by the 23rd week of gestation the cochlea attains its adult dimensions and the periotic spaces are well formed.9COMMENTIn 1946, McClure reported a nasopharyngeal odontoma.1This only recorded case of an extragnathic odontoma was a true choristoma. He reviewed a large series of nasopharyngeal tumors and found no mention of an odontoma. Odontogenic craniopharyngioma is also reported to occur and perhaps an embryologic relationship can be inferred.10Embryology explains the possible mechanism of the occurrence of middle ear odontoma, nasopharyngeal odontoma, and odontogenic craniopharyngioma. At some stage of differentiation, dental anlage cells may migrate caudad within the foregut lumen to the primordium of the nasopharynx or rostral to the Rathke pouch. This may possibly occur at the third week of gestation, when the buccopharyngeal membrane ruptures and connects the stomodeum to the foregut.11Ectodermal cells that are to form the dental laminae come to rest against the entoderm in the region of the first pharyngeal pouch or at the Rathke pouch. Another alternative is the de novo appearance of ameloblasts in the first branchial arch or area of the Rathke pouch.The Eustachian tube that develops as a lateral outpouching of the first pharyngeal pouch forms the middle ear cleft. In the process, this tube may carry ectopic primordial dental anlage cells to the developing middle ear cavity, where dental development would then occur with formation of a dental mass. If this were to happen, the tooth forms would be within the middle ear's mucosa-lined cavity. However, the dental masses would be mucosa covered if pushed to the region by an entodermal outgrowth. Odontogenic cells located adjacent to the primordial first pharyngeal pouch area could develop as a nasopharyngeal odontoma. Alternatively, if the odontogenic cells were lying in the primordial Rathke pouch, they could be carried toward the developing site of the hypophysis and develop into an odontogenic craniopharyngioma.ReferencesMcClure G. Odontoma of the nasopharynx. Arch Otolaryngol.1946;44:51-60.Gorlin RJ, Goldman HM. Thoma's Oral Pathology. St. Louis, CV Mosby Co, 1970, vol 1, pp 497-501.Robbins SL. Pathology. Philadelphia, WB Saunders Co, 1967, vol 2, chap 20, pp 770-817.Zegarelli EV, Dutscher AH, Hyman GA. Diagnosis of Disease of the Mouth and Jaws. Philadelphia, Lea & Febiger Publishers, 51969, pp 214-217.Shanks SC, Kerley P. A Text-Book of X-Ray Diagnosis, ed 4. Philadelphia, WB Saunders Co, 1969, vol 1, chap 19, pp 517-519.Gorlin RJ, Meskin LH, Brodey R. Odontogenic tumors in man and animals: Pathologic classification and clinical behavior: A review. Ann NY Acad Sci. 1963;108:722-771.Langman J. Medical Embryology. Baltimore, Williams & Wilkins Co, 1963, pp 197-211, 293-302, 316-318.Ward GE, Hendrick JW. Tumors of the Head and Neck. Baltimore, Williams & Wilkins Co, 1957, pp 44-49, 341-344.Papparella MM, Shumrick DA. Otolaryngology. Philadelphia, WB Saunders Co, 1973, vol 1, chap 1, pp 3-74.Kalnins V, Rossi E. Odontogenic craniopharyngioma. Cancer. 1965;19:899-906.Arey LB. Developmental Anatomy, ed 7. Philadelphia, WB Saunders Co, 1965, pp 541-550.Submitted for publication February 17, 2003; final revision received April 30, 2004; accepted May 14, 2004.The Kaiser Permanente Community Benefit Program provided research support.The Kaiser Foundation Hospitals, Inc, Medical Editing Department provided editorial assistance.Correspondence: Barry Rasgon, MD, Department of Head and Neck Surgery, Kaiser Permanente Medical Center, 280 W MacArthur Blvd, Oakland, CA 94611 (barry.rasgon@kp.org).

Journal

JAMA Otolaryngology - Head & Neck Surgery – American Medical Association

Published: Oct 1, 2004

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