Intracardiac malignant nonchromaffin paraganglioma (chemodectoma) in a cat.

A 5-year-old male castrated Domestic Shorthair cat was presented to a veterinary specialty hospital for evaluation of large-volume pleural effusion. Echocardiography revealed a large intracardiac mass at the level of the interatrial septum impairing right atrial inflow resulting in lymphocytic pleural effusion and ascites. Differential diagnoses included lymphoma, hemangiosarcoma, rhabdomyosarcoma, chemodectoma, neurofibrosarcoma, myxoma, metastatic carcinoma or intracardiac thrombus, abscess or granuloma. Due to poor long-term prognosis and recurrent, large-volume pleural effusion, the cat was humanely euthanized. The heart was submitted for histopathologic evaluation. The mass was subsequently determined to be a malignant extra-adrenal nonchromaffin paraganglioma (chemodectoma) arising from the pulmonary trunk near its bifurcation in the region of the glomus pulmonale. Chemodectomas are rare in cats and to the authors' knowledge, there are no reports of one originating from the glomus pulmonale.

Alveolar type II cells expressing jaagsiekte sheep retrovirus capsid protein and surfactant proteins are the predominant neoplastic cell type in ovine pulmonary adenocarcinoma.

Ovine pulmonary adenocarcinoma is caused by jaagsiekte sheep retrovirus. To gain insight into the histogenesis and viral pathogenesis of this neoplasm, the tumor cell phenotypes and differentiation state were correlated with the distribution of jaagsiekte sheep retrovirus capsid protein in neoplastic and normal cells of the lung in nine naturally occurring and 12 experimentally induced cases of ovine pulmonary adenocarcinoma. Overall, 82% of tumor cells had ultrastructural features consistent with alveolar type II cells, 7% of tumor cells had features of Clara cells, and 11% of tumor cells were insufficiently differentiated to classify. The proportion of the neoplastic cell phenotypes varied within tumors, and no tumor consisted of a morphologically uniform cell population. To further characterize the neoplastic cell population, sections of tumors were immunostained with antibodies to surfactant protein A, surfactant protein C, and Clara cell 10-kd protein. Overall, surfactant proteins A and C were expressed in 70% and 80% of tumor cells, respectively, whereas Clara cell 10-kd protein was expressed in 17% of tumor cells. Jaagsiekte sheep retrovirus capsid protein was detected in 71% of tumor cells and in macrophages (5/21 tumors examined) and in nonneoplastic alveolar and bronchiolar cells (6/14 tumors). Expression of this viral protein in neoplastic cells, classified morphologically and by immunophenotyping primarily as of the alveolar type II lineage, implies an important role for specific virus-cell interactions in the pathogenesis of ovine pulmonary adenocarcinoma.

Bovine abortions associated with Bacteroides fragilis fetal infection.

Two Santa Gertrudis cattle from a herd of 105 aborted within a 24-hour period. Bacteroides fragilis was isolated from tissues of each aborted fetus. Histopathologic lesions included placentitis and bronchopneumonia in which gram-negative, rod-shaped organisms were visible. The diagnostic workup failed to reveal other causes of abortion. Anaerobes are rarely implicated in bovine abortions, and no other report was found that described abortion in cattle due to B. fragilis.