Veterinary Pathology

Harvey, J. W.; Shields, R. P.; Gaskin, J. M.

doi: 10.1177/030098587801500401pmid: 695218

A 4 1/2-year-old cat had myeloproliferative disease characterized by severe anemia. Peripheral blood had a profusion of relatively normal-appearing nucleated erythroid cells in all stages of development and a few primitive cells with nucleoli. The term “erythremic myelosis” best described the appearance of the peripheral blood. Two weeks later, the peripheral blood picture was that of regenerative anemia. During the next 2 months the cat made an apparent clinical recovery without treatment, but relapsed 3 months after the initial examination. One-fourth of the cells in circulation at the time of relapse contained nucleoli and appeared identical to those described in reticuloendotheliosis in cats. This transition suggested the progressive development of a greater degree of immaturity of erythroid precursors with time. The use of the term “reticuloendotheliosis” in conjunction with feline myeloproliferative disease was considered and determined inappropriate.

Shadduck, J. A.; Bendele, R.; Robinson, G. T.

doi: 10.1177/030098587801500402pmid: 695219

Spontaneous infection with Encephalitozoon cuniculi resulted in a lethal disease in all but one of a litter of puppies in Texas. The disease was characterized by severe nonsuppurative nephritis, encephalitis and segmental vasculitis. Many protozoa were in renal tubule cells, endothelial cells and brain. The number of organisms decreased and the granulomatous character of the lesions became more prominent as the disease progressed. Sera from affected puppies and their parents reacted in an indirect immunofluorescence test with canine E. cuniculi propagated in vitro. The sera of owners of affected pups were negative.

Frese, K.

doi: 10.1177/030098587801500403pmid: 695220

Progressive studies in dogs with skin and oral melanomas were undertaken to determine whether or not the WHO-classification of melanomas, which is based mainly on histological criteria, reflects sufficiently the biological behaviour of these tumours. Furthermore, some prognostic parameters, important in the prognosis of human malignant melanomas were tested with respect to their significance for canine melanomas.The paper deals with progressive studies in 182 dogs with surgically treated benign and malignant skin and oral melanomas. Parameters of the biological behaviour were the 2 years death rate and the median survival time. The melanomas were classified according to the recommendations of the WHO.Within 2 years after the first treatment five (5.7%) of 87 dogs with benign skin melanomas, 29 (65.9%) of 44 dogs with malignant skin melanomas and 44 (86.2%) of 55 dogs with malignant oral melanomas were killed because of recurrence or metastases or both. The median survival time of dogs with benign skin melanomas was more than 24 months, with malignant skin melanomas 8 months and with malignant oral melanomas 3 months. In dogs with large malignant skin melanomas the 2 years death rate was 100% with a median survival time of 4 months, whereas animals with small melanomas had a 2 years death rate of 54.3% and a median survival time of 12 months. The site of skin melanomas, sex and histological type of both skin and oral melanomas, however, had no significant influence on the course of the disease. Also, histological parameters, important in the prognosis of human malignant melanoma (rate of mitosis, size of nucleoli, pigmentation and vascular invasion), had no significant influence on the course of the disease.

van der Linde-Sipman, J. S.

doi: 10.1177/030098587801500404pmid: 695221

Two different congenital malformations of the heart were seen in two calves and two ewe lambs. In all these malformations the left ventricle was more or less hypoplastic; it was small with a narrow lumen and a thick wall. In one malformation the aorta began as a cul-de-sac above the left ventricle; in the other, the aorta arose from the right ventricle, to the right of the supraventricular crest.

Vuletin, J. C.; Friedman, H.; Gordon, W.

doi: 10.1177/030098587801500405pmid: 695222

A tumor mass removed from the subcutaneous tissue of the shoulder of a dog had the light and electron microscopic features of extraneuraxial meningioma. The neoplasm probably arose from arachnoid cap cells displaced during embryogenesis.

Eagle, R. C.; Font, K. L.; Swerczek, T. W.

doi: 10.1177/030098587801500406pmid: 695223

An 18–month-old Standardbred filly had a large intraocular tumor involving the optic nerve. The tumor was a malignant medulloepithelioma, a rare intraocular neoplasm derived from the primitive medullary epithelium. By light microscopy the tumor had cords and lobules of primitive neuroepithelial cells that formed clefts and true rosettes. Electron microscopy of the rosettes showed a girdle of zonulae adherentes joining the apices of the cells as well as several basal bodies. This is the sixth report of equine intraocular medulloepithelioma, and, to the best of our knowledge, the first intraocular medulloepithelioma arising from the optic nerve head in a horse. Massive involvement of the optic nerve should be suspected when an eye containing an intraocular mass in the posterior segment lacks light perception. In such cases a long segment of optic nerve should be resected.

Cheema, A. H.; Ivoghli, B.

doi: 10.1177/030098587801500407pmid: 695224

Onchocerca armillata was found in 284 (28%) of 1,016 aortas, and O. gutturosa in 82 (28.87%) of 284 nuchal ligaments and in 11 (7.85%) of 140 rumenosplenic areas in specimens from cattle slaughtered during a 12-month period. Adult parasites were not found in 600 hides. Gross lesions included parasitic tunnels, nodules, roughening and calcification in the aortic walls. The connective tissue of nuchal ligaments and rumenosplenic areas was increased in amount, was gelatinous and brown and had a few nodules. Microscopically there were acute changes with oedema, haemorrhages and cellular infiltrations predominantly by eosinophils. There were chronic granulomatous reactions characterized by accumulation of macrophages, lymphocytes, plasma cells, giant cells, calcification and fibrosis around degenerate and dead parasites. Neutral fat was in parasites and surrounding cells. Both changes often occurred in the same specimen and many samples had parasites but no tissue reaction. Hypersensitivity, foreign-body reactions and parasitic toxins apparently were involved in the genesis of these lesions.

Bestetti, G.

doi: 10.1177/030098587801500408pmid: 695225

The granules (Drusen) within the inflammatory lesions in three cases of infection by Actinomyeetales were studied with light and electron microscopy. The material consisted of subcutaneous granulomas caused by Actinomyces bovis in a cow, epidural granulomas caused by A. viscosus in the spinal canal of a cat and cerebral granulomas caused by Nocardia in a dog.The granules of A. bovis were 2000 to 3000 micrometers in diameter. Their centers consisted of a slightly basophilic, gram- and grocott-negative material with branching, gram-and grocott-positive filaments. The periphery was slightly basophilic or eosinophilic, but gram- and grocott-positive. Its surface was made of clubs (15 × 3.5 micrometers); they were acidophilic, gram- and grocott-negative. In the center of the granule there are numerous type a cells (coccobacillary cells with a trilaminar cell wall of 12 nanometers) and rarely type b cells (filaments with bilaminar cell wall of 30 nanometers). The periphery was made of germinative centers of type a cells. The clubs were lytic type b cells, embedded in an amorphous material.The granules (Drusen) of A. viscosus were 200 to 600 micrometers in diameter. Their center was slightly eosinophilic, gram- and grocott-negative and contained gram- and grocott-positive filaments. Their periphery was basophilic and contained alternating gram-and grocott-negative areas and radial gram- and grocott-positive filaments. There were no clubs. In the center there were type b cells (filaments with a trilaminar cellular wall of 30 nanometers). The periphery was made of germinative centers of type a cells (coccobacillary with a trilaminar cell wall of 10 to 11 nanometers). The germinative centers were separated from each other by radial bundles of type b cells.The granules (Drusen) of Nocardia were acidophilic, gram- and grocott-positive and surrounded by 1.8 × 0.5-micrometer clubs that were acidophilic, gram- and grocott-negative. There were type a cells (filamentous to bacillary with monolaminar cell wall of 19 nanometers and cross wall) and type b cells (filamentous to bacillary with monolaminar cell wall of 65 nanometers and without cross wall).The remarkable morphological differences of the three species of Actinomycetales are specific, independent from host and type of tissue, and therefore reliable for diagnostic purposes.

Gopal, T.; Leipold, H. W.; Cook, J. E.

doi: 10.1177/030098587801500409pmid: 695226

Kidney tissues were collected from 142 calves during a study of pre- and perinatal mortality. Fifty-six calves had oxalate crystals in their renal tissue. Thirty-four of the 56 had either single or multiple congenital defects, mostly of the skeleton. Twenty-two of the 56 died of causes other than congenital defects. The renal oxalosis was more pronounced in those calves affected with congenital anomalies.

Bishop, L.

doi: 10.1177/030098587801500410pmid: 695227

A solid and cystic suprasellar teratoma was found in a rabbit killed because of incoordination. The tumor consisted of neural cells, cysts lined by various types of epithelium, respiratory mucosa, gastric mucosa, mucous and mucoserous glands, collagenous connective tissue, cartilage and fat.