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A 10-Week-Old Boy With a Telangiectatic Nodule on the Knee—Diagnosis

A 10-Week-Old Boy With a Telangiectatic Nodule on the Knee—Diagnosis Diagnosis: Giant juvenile xanthogranuloma (JXG). Microscopic findings An excisional biopsy specimen demonstrated a proliferation of histiocytelike mononuclear cells with abundant eosinophilic cytoplasm. The proliferation extended from just below the epidermis into the subcutaneous fat. A few mitotic figures were present along with scattered lymphocytes and eosinophils. The lesional cells were positive for CD68 and factor XIIIa and negative for cytokeratins AE1/3, S100 protein, smooth muscle actin, and desmin. Discussion Giant, or macronodular, JXGs are larger than 2 cm in diameter and are an uncommon cutaneous subtype of JXG. Unlike classic JXGs, giant JXGs have been described only in children to date. A review of 12 cases of giant JXG described in the literature showed that, compared with classic JXGs, giant JXGs are more likely to occur in girls, to be congenital, and to involve the proximal aspect of the extremities or upper back area.1 A case of a giant JXG on the tongue of a 6-year-old girl has also been reported.2 Our patient's nodule had a period of rapid growth over several weeks, a feature also described in previously reported cases. The initial clinical impression in our patient was dermatofibrosarcoma protuberans. The clinical differential diagnosis also includes rhabdomyosarcoma, giant cell fibroblastoma, and other soft tissue neoplasms. In well-developed JXGs that are composed of foamy histiocytes and numerous Touton giant cells, the diagnosis is straightforward; however, less well-developed JXGs may not demonstrate these classic findings. Touton giant cells are often absent (as in our case), and the foamy cytoplasm of the histiocytes may not be readily apparent. Thus, immunohistochemical studies, and sometimes electron microscopy, are needed for diagnosis.3 The vast majority of JXGs are positive for the macrophage marker CD68. Also, most JXGs are positive for factor XIIIa and negative for CD1a and S100 protein.3 Electron microscopy is negative for Birbeck granules. The pathogenesis of JXG is believed to be reactive rather than neoplastic in nature.1,4 Unlike Langerhans cell histiocytoses, in which the cell of origin has been identified, the cell of origin for non–Langerhans cell histiocytoses remains undefined. A recent immunophenotypic study of JXGs concluded that the cell of origin for JXGs is not the dermal dendrocyte, as previously suggested. Rather, the phenotype of lesional cells of JXGs is consistent with that of plasmacytoid monocytes: circulating bone marrow–derived dendritic cell precursors.4 The clinical course of giant JXGs appears similar to that of classic JXGs, with spontaneous involution and resolution.1,5,6 Thus, it appears that larger size does not adversely affect the prognosis. Given the benign nature of giant JXGs, observation is recommended. However, in symptomatic cases with spontaneous bleeding or functional impairment due to mass effect, excision may be preferable.5,7 To date, extracutaneous JXG has not been described in association with giant JXGs.1 However, there have been few reported cases of giant JXGs. Therefore, it appears prudent to screen for ocular involvement. References 1. Chang M Update on juvenile xanthogranuloma: unusual cutaneous and systemic variants Semin Cutan Med Surg. 1999;18195- 205PubMedGoogle ScholarCrossref 2. Shapiro NLMalis DJCharon CCBillman GFKearns DB Giant juvenile xanthogranuloma of the tongue Am J Otolaryngol. 1999;20241- 244PubMedGoogle ScholarCrossref 3. Lazova RShapiro PE Juvenile xanthogranuloma versus langerhans cell histiocytosis (histiocytosis X) Semin Cutan Med Surg. 1999;1871- 77PubMedGoogle ScholarCrossref 4. Kraus MDHaley JCRuiz REssary LMoran CAFletcher CDM "Juvenile" xanthogranuloma: an immunophenotypic study with reappraisal of histogenesis Am J Dermatopathol. 2001;23104- 111PubMedGoogle ScholarCrossref 5. Resnick SDWoosley JAzizkhan RG Giant juvenile xanthogranuloma: exophytic and endophytic variants Pediatr Dermatol. 1990;7185- 188PubMedGoogle ScholarCrossref 6. Magana MVazquez RFernandez-Diez JFlores-Villa RCazarin J Giant congenital juvenile xanthogranuloma Pediatr Dermatol. 1994;11227- 230PubMedGoogle ScholarCrossref 7. Bazan ALasso JMElejabeitia JTutor EG Giant juvenile xanthogranuloma present since birth Ann Plast Surg. 1998;41335- 336PubMedGoogle Scholar http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Archives of Dermatology American Medical Association

A 10-Week-Old Boy With a Telangiectatic Nodule on the Knee—Diagnosis

Archives of Dermatology , Volume 140 (2) – Feb 1, 2004
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A 10-Week-Old Boy With a Telangiectatic Nodule on the Knee—Diagnosis

Abstract

Diagnosis: Giant juvenile xanthogranuloma (JXG). Microscopic findings An excisional biopsy specimen demonstrated a proliferation of histiocytelike mononuclear cells with abundant eosinophilic cytoplasm. The proliferation extended from just below the epidermis into the subcutaneous fat. A few mitotic figures were present along with scattered lymphocytes and eosinophils. The lesional cells were positive for CD68 and factor XIIIa and negative for cytokeratins AE1/3, S100 protein, smooth muscle...
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References (7)

Publisher
American Medical Association
Copyright
Copyright © 2004 American Medical Association. All Rights Reserved.
ISSN
0003-987X
eISSN
1538-3652
DOI
10.1001/archderm.140.2.231-d
Publisher site
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Abstract

Diagnosis: Giant juvenile xanthogranuloma (JXG). Microscopic findings An excisional biopsy specimen demonstrated a proliferation of histiocytelike mononuclear cells with abundant eosinophilic cytoplasm. The proliferation extended from just below the epidermis into the subcutaneous fat. A few mitotic figures were present along with scattered lymphocytes and eosinophils. The lesional cells were positive for CD68 and factor XIIIa and negative for cytokeratins AE1/3, S100 protein, smooth muscle actin, and desmin. Discussion Giant, or macronodular, JXGs are larger than 2 cm in diameter and are an uncommon cutaneous subtype of JXG. Unlike classic JXGs, giant JXGs have been described only in children to date. A review of 12 cases of giant JXG described in the literature showed that, compared with classic JXGs, giant JXGs are more likely to occur in girls, to be congenital, and to involve the proximal aspect of the extremities or upper back area.1 A case of a giant JXG on the tongue of a 6-year-old girl has also been reported.2 Our patient's nodule had a period of rapid growth over several weeks, a feature also described in previously reported cases. The initial clinical impression in our patient was dermatofibrosarcoma protuberans. The clinical differential diagnosis also includes rhabdomyosarcoma, giant cell fibroblastoma, and other soft tissue neoplasms. In well-developed JXGs that are composed of foamy histiocytes and numerous Touton giant cells, the diagnosis is straightforward; however, less well-developed JXGs may not demonstrate these classic findings. Touton giant cells are often absent (as in our case), and the foamy cytoplasm of the histiocytes may not be readily apparent. Thus, immunohistochemical studies, and sometimes electron microscopy, are needed for diagnosis.3 The vast majority of JXGs are positive for the macrophage marker CD68. Also, most JXGs are positive for factor XIIIa and negative for CD1a and S100 protein.3 Electron microscopy is negative for Birbeck granules. The pathogenesis of JXG is believed to be reactive rather than neoplastic in nature.1,4 Unlike Langerhans cell histiocytoses, in which the cell of origin has been identified, the cell of origin for non–Langerhans cell histiocytoses remains undefined. A recent immunophenotypic study of JXGs concluded that the cell of origin for JXGs is not the dermal dendrocyte, as previously suggested. Rather, the phenotype of lesional cells of JXGs is consistent with that of plasmacytoid monocytes: circulating bone marrow–derived dendritic cell precursors.4 The clinical course of giant JXGs appears similar to that of classic JXGs, with spontaneous involution and resolution.1,5,6 Thus, it appears that larger size does not adversely affect the prognosis. Given the benign nature of giant JXGs, observation is recommended. However, in symptomatic cases with spontaneous bleeding or functional impairment due to mass effect, excision may be preferable.5,7 To date, extracutaneous JXG has not been described in association with giant JXGs.1 However, there have been few reported cases of giant JXGs. Therefore, it appears prudent to screen for ocular involvement. References 1. Chang M Update on juvenile xanthogranuloma: unusual cutaneous and systemic variants Semin Cutan Med Surg. 1999;18195- 205PubMedGoogle ScholarCrossref 2. Shapiro NLMalis DJCharon CCBillman GFKearns DB Giant juvenile xanthogranuloma of the tongue Am J Otolaryngol. 1999;20241- 244PubMedGoogle ScholarCrossref 3. Lazova RShapiro PE Juvenile xanthogranuloma versus langerhans cell histiocytosis (histiocytosis X) Semin Cutan Med Surg. 1999;1871- 77PubMedGoogle ScholarCrossref 4. Kraus MDHaley JCRuiz REssary LMoran CAFletcher CDM "Juvenile" xanthogranuloma: an immunophenotypic study with reappraisal of histogenesis Am J Dermatopathol. 2001;23104- 111PubMedGoogle ScholarCrossref 5. Resnick SDWoosley JAzizkhan RG Giant juvenile xanthogranuloma: exophytic and endophytic variants Pediatr Dermatol. 1990;7185- 188PubMedGoogle ScholarCrossref 6. Magana MVazquez RFernandez-Diez JFlores-Villa RCazarin J Giant congenital juvenile xanthogranuloma Pediatr Dermatol. 1994;11227- 230PubMedGoogle ScholarCrossref 7. Bazan ALasso JMElejabeitia JTutor EG Giant juvenile xanthogranuloma present since birth Ann Plast Surg. 1998;41335- 336PubMedGoogle Scholar

Journal

Archives of Dermatology – American Medical Association

Published: Feb 1, 2004

Keywords: knee region,knee joint

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