Pathological Characterization of Lymphoma with Pulmonary Involvement in Cats.

Studies evaluating histological patterns of lung infiltration by lymphoma in cats are lacking. We evaluated retrospectively the histological patterns of 125 necropsy cases of feline lymphoma collected over a 12-year period. Of the 125 cases, 16 showed lung infiltration (12.8%). Nine cats were female, seven cats were male and all were of mixed breed. Gross lesions observed in the lungs consisted of masses (25%) and nodules (18.7%); however, the majority of cases (56.2%) did not show any gross abnormality. Peribronchial-vascular infiltration (93.7%) was the most frequent pattern, followed by pleural (56.2%), interstitial (50%), nodular (37.5%) and alveolar (12.5%) patterns, but 75% of the cases had more than one pulmonary infiltration pattern. There were 14 (87.5%) B-cell and two (12.5%) T-cell lymphomas. Six cats (37.5%) were positive for feline leukaemia virus and three cats (18.7%) were positive for feline immunodeficiency virus. Diffuse large B-cell lymphoma was the most frequent type, accounting for 56% of all cases.

Neurotoxicosis in horses associated with consumption of Trema micrantha.

BACKGROUND: Trema micrantha is a tree widely distributed throughout the Americas. The tree produces highly palatable leaves that have been associated with natural poisoning in goats, sheep and horses, in which hepatic necrosis and hepatic encephalopathy have been observed. OBJECTIVES: This study describes malacia and haemorrhage in the central nervous system (CNS) due to T. micrantha consumption, with minimal to absent hepatic lesions. STUDY DESIGN: Retrospective case series. METHODS: A total of 14 horses with a history of neurological signs and spontaneous consumption of T. micrantha leaves were submitted to necropsy and multiple samples were collected for histopathology. Details of clinical history and signs of the horses were obtained through inquiries to the owners and attending veterinarians. RESULTS: All the 14 horses had neurological signs of ataxia, severe sialorrhoea, involuntary running movements, sternal and lateral recumbency, and death after a clinical course that lasted from 24 h to 9 days. For a few days prior to onset of clinical signs, all horses had spontaneously consumed, potentially toxic doses of T. micrantha leaves. All 14 brains had diffuse yellowish discoloration affecting the rhombencephalon, mesencephalon, diencephalon, telencephalon and corpus striatum. In all cases, the most severe lesions were observed in the pons. Spinal cord lesions were observed affecting the lumbar intumescence, which was swollen with darken and depressed areas at the dorsal and ventral horns, and at the sacral level, which on cut surface displayed a friable and yellowish grey matter. The lesions observed grossly in brain and spinal cord consisted microscopically of severe vasculitis and liquefactive necrosis of white and grey matter of the brainstem, cerebellum and spinal cord. MAIN LIMITATIONS: This is a small retrospective series relying on clinical observations reported by owners and attending veterinarians. The mechanism of action of the plant toxin in the CNS is still unidentified. CONCLUSION: T. micrantha poisoning in horses causes predominantly a neurological disease, with minimal to absent hepatic lesions.