Pigeon herpesvirus: inclusion body hepatitis in a free-ranging pigeon.

An adult male pigeon (Columba livia) was presented to the Wildlife Service at the University of Pennsylvania School of Veterinary Medicine for depression, cachexia, and diarrhea. Five days after the initial presentation, the bird died and was necropsied. Gross lesions included opaque air sacs and multiple 1-mm yellow-white foci on the epicardial surface of the heart. Histopathologic lesions included a pericarditis, epicarditis, and multifocal hepatic necrosis accompanied by eosinophilic inclusion bodies. Ultrastructural examination of the hepatic inclusions revealed viral particles consistent with a herpesvirus. The gross, light microscopic, and electron microscopic findings are consistent with pigeon herpesvirus infection.

Calcifying epithelial odontogenic tumours in three cats and a dog.

Neoplasms histologically similar to calcifying epithelial odontogenic tumour (CEOT) of man are described in three cats and a dog. The diagnostic features of these neoplasms are their occurrence in the jaw and the histological appearance of cords of epithelial cells, amyloid spherules and foci of calcification. The histogenesis and behaviour of the tumour are discussed.

Canine multilobular osteosarcoma of the skull with metastasis.

A 6-year-old crossbreed dog had recurring nodular masses on the dorsum of the head which were diagnosed as multilobular osteosarcoma. At necropsy, metastases were present throughout the lungs. Histological features of the masses included multiple islands of cartilage and bone separated by a dense fibrovascular stroma. These tumours are slow growing malignant neoplasms which may metastasize.

Craniopharyngioma in a dog.

Craniopharyngiomas are rare in dogs. A 3 cm suprasellar craniopharyngioma in a 13-month-old male mongrel dog is described. The mass consisted of multiple microcysts and solid areas with mesenchymal proliferation in areas of transition. Tumour cells were arranged in solid sheets or separated into islands by thick bands of collagen. Squamous differentiation of tumour cells with keratin formation and a focus of osseous metaplasia were present. Occasionally, tumour cells were arranged in rosettes. Cysts were lined by a single layer of cuboidal to low columnar epithelium and contained proteinaceous fluid with numerous cholesterol clefts. The diagnosis was based on age of occurrence, location and histological appearance.

Metastasis of a well-differentiated liposarcoma in a dog and a note on nomenclature of fatty tumours.

A slow-growing mass in the left thigh of a 7-year-old spayed female fox terrier dog was originally diagnosed as an infiltrative lipoma by surgical biopsy. Necropsy findings one year later revealed multiple masses made up of well-differentiated adipocytes in the spleen, liver, lungs and a lymph node. The final histopathological diagnosis of these masses and, in retrospect, for the initial leg mass was well-differentiated liposarcoma. This case illustrates some of the confusion in current nomenclature of fatty tumours. Tumours made up of well-differentiated adipose cells which show no tendency toward invasion of surrounding tissue should be designated lipomas. We suggest that fatty tumours characterized by local tissue invasion and/or metastasis should be classified as liposarcomas. Liposarcomas may be further subdivided into well-differentiated and poorly-differentiated types.

Lead poisoning of raccoons in Connecticut.

A wild raccoon (Procyon lotor) had clinical signs, histopathologic and ultrastructural lesions indicative of lead intoxication. The diagnosis was confirmed by chemical analyses of liver and kidney tissues which revealed 35 ppm of lead in wet tissues. A survey of hepatic lead concentration in 13 additional raccoons was conducted.

Toxoplasmosis, distemper, and herpesvirus infection in a skunk (Mephitis mephitis).

A striped skunk (Mephitis mephitis) showing abnormal behavior had histopathologic lesions of toxoplasmosis and canine distemper in addition to intranuclear, eosinophilic inclusions in the reticuloendothelial cells of the spleen, liver and lung. The inclusions, on electron microscopic examination, were compatible with herpesvirus infection.

Bone marrow and hematologic values of wild raccoons.

Blood and bone marrow samples were obtained from wild raccoons in the State of Connecticut to determine leukocyte and erythrocyte counts, hemoglobin, hematocrit, and peripheral blood and bone marrow differential counts. Calculations were made to determine mean corpuscular volume, mean corpuscular hemoglobin, and mean corpuscular hemoglobin concentration.

Clinical and pathologic features of canine ocular melanomas.

Ocular melanomas in 40 dogs were reviewed and classified by site of origin and cytologic features. An apparent correlation existed between site, cytologic classification, and prognosis. Limbal melanomas and intraocular melanomas classified as spindle A or spindle B were less aggressive and had a more favorable prognosis than intraocular melanomas classified as a mixed-cell type or epithelioid.

Poxvirus and multiple tumors in an eastern gray squirrel.

A moribund juvenile gray squirrel (Sciurus carolinensis) with numerous skin fibromas was submitted to the Northeastern Research Center for Wildlife Diseases. Necropsy revealed multiple firm white nodules in the lungs. On histologic examination, in addition to the skin lesions, fibromatous proliferations were seen in the wall of the alimentary tract, in 1 mesenteric lymph node, and in the myocardium. Tubular adenomas were seen in the renal cortex, and the lung nodules were bronchoalveolar adenomas. Eosinophilic intracytoplasmic poxvirus inclusion bodies were seen in both the mesenchymal and epithelial tumors.

Ureteral fibropapilloma in a dog.

A fibropapilloma was found to involve the left ureter in a 7-year-old castrated male Doberman Pinscher dog. Severe unilateral hydronephrosis and hydroureter were associated with the ureteral mass. Treatment consisted of unilateral nephrectomy and ureterectomy. This case represents an additional type of primary ureteral neoplasm found in the dog.

Hermaphroditism in a Sprague-Dawley rat.

A spontaneous case of unilateral true hermaphroditism was observed during the routine necropsy of a 9-week-old presumed female Sprague-Dawley rat on a repeat-dose toxicity study. There were no drug-related effects observed. True hermaphroditism is rare in rats, and despite the large numbers of rats examined annually, few cases are reported in the literature.

Atrioventricular valvular angiectasis in Sprague-Dawley rats.

Subendothelial heart valve angiectasis has been reported in cows, dogs, pigs, rats, mice, and in human fetuses and newborns. We observed a high incidence (62 in 208 animals examined) of spontaneous angiectasis on the atrioventricular (AV) valves in 10- to 40-week-old Sprague-Dawley rats. The angiectasis was observed predominately on the septal cusp of the right AV valve and located near the AV ostium in 57 of 62 animals. Of the remaining 5 valvular angiectases, 2 were present on the parietal cusp of the right AV valve and 3 were on the left AV valve. The angiectases were single or multiple, ranging from 40 to 300 microm in diameter and were characterized by light microscopy as blood-filled dilatations lined by endothelium. Spontaneously occurring abnormalities in normal laboratory animals, such as the spontaneous valvular angiectasis reported here, need to be differentiated from drug-related lesions.

Feline basal cell tumors: a review of 124 cases.

Basal cell tumors from 124 cats of six breeds which represented 4.2% of feline neoplasms and 10.9% of feline cutaneous neoplasms are characterized. The mean age of cats affected was 9.6 years, and an increased risk was correlated positively with increasing age (rxy = +0.85). Males, females, and castrates were affected equally. Long-haired breeds were at higher risk (p less than 0.01) for development of basal cell tumors which had two major histologic types--solid and cystic. No site predilection was apparent.

Vegetative endocarditis with generalized bacterial embolism in association with phlegmon induced by Dracunculus insignis in a raccoon.

Lesions of streptococcal vegetative endocarditis and subsequent embolic disease are described in a raccoon (Procyon lotor). A phlegmon of the animal's forelimb associated with Dracunculus insignis infestation was believed to be the primary site of bacterial invasion.

Primary ocular melanoma in dogs.

The clinical signs, gross and microscopic appearance, treatment, and follow-up results of 35 dogs with primary ocular melanomas are reviewed. The melanomas are classified as epibulbar or intraocular based on the site of origin. The intraocular tumors are classified as spindle A, spindle B, mixed spindle B and epithelioid, and purely epithelioid based on cytologic criteria. The pathologic findings are matched with the follow-up history in an attempt to determine which features have prognostic significance. The findings are contrasted to those of similar studies of spontaneous ocular melanomas in man.

Clinical and clinicopathological assessment of serial phlebotomy in the Sprague Dawley rat.

Two studies, designed to mimic a single-dose, cross-over pharmacokinetic protocol, were conducted to gain a better understanding of the rat's response to multiple, frequent blood sampling. Parameters evaluated included body weight, clinical signs of disease, hematologic and serum biochemical analytes, organ weights, and histopathologic features. Study groups consisted of either 6 or 8 male, viral antibody-free, Sprague Dawley rats. These included controls and blood-collection groups that represented withdrawal of 10, 15, 20, 30, and 40% of estimated total blood volume. Volume of blood collected per time point was based on the total volume to be withdrawn divided by the 13 samples that were collected over 24 h. This regimen was repeated 2 weeks later. Samples were taken for clinical pathologic evaluation on the days subsequent to blood collection for both studies as follows: 0, 1, 2, and 3 days; 7, 8, or 9 days; and either 13 or 14 days. In Study 1, samples were also taken on either days 15 or 16, and on 17 or 18 after the second blood collection. Approximately 2 weeks after the second blood collection regimen, animals were euthanized. Animals in one study were necropsied, and selected tissues were taken for histologic examination. Analysis of variance, based on changes from baseline, was used to assess group differences. Results indicate that the rate of body-weight gain for the bled groups was not significantly different from that of the controls. Group differences in multiple hematologic parameters were significant. Changes were typical of acute blood-loss anemia, with positive or negative trends relating to the volume of blood removed. In addition, these changes were characterized by recovery to control values within approximately 14 days. Few statistically significant group differences were detected in serum biochemical values, and those detected were not biologically relevant. Although organ weights of bled groups were similar to those of controls, minimal to mild splenic hematopoiesis was present in all bled groups, compared with controls. These data indicate that removal of up to 40% of a rat's total blood volume over a 24-h period, and repeated 2 weeks later, caused no gross ill effects.

Choroidal melanomas in dogs.

The clinical and morphological features of intraocular melanocytic masses that originated in the choroid of five dogs were compared. Two of the cases had been reported previously and the authors have examined the pathological material. Histologically, the choroidal melanocytic tumors had several features in common and appeared to be entities distinct from melanocytic tumors of the anterior uveal tract or the epibulbar region. The tumors were well-delineated with tapered edges. They occurred in the posterior quadrant and two tumors had infiltrated the optic nerve. The tumors contained plump, strap-like polyhedral cells, with minimal nuclear anaplasia and no mitotic figures. The retina overlying the tumor mass was detached, and the retinal pigment epithelium in this area was swollen and contained intracytoplasmic autofluorescent lipopigment. In two cases, the basement membrane of the retinal epithelium was disrupted by the tumor and pigmented cells infiltrated into the retina, the subretinal space, and the posterior chamber. In one case, retinal detachment was complete and accompanied by intraocular hemorrhage. Melanocytic tumors of the canine choroid have features in common with choroidal nevus and melanocytoma in human eyes.