PRIMARY MENINGEAL T-CELL LYMPHOMA IN A HARBOR SEAL (PHOCA VITULINA)

EPITHELIOTROPIC INTESTINAL T-CELL LYMPHOMA IN A HARBOR SEAL (PHOCA VITULINA)

A 14-yr- old, male harbor seal ( Phoca vitulina ) presented with depression, anorexia, and weight loss. Clinical examination revealed no specific abnormalities. Diagnostic imaging displayed an enlarged mass in the dorso-cranial abdomen. The animal was euthanized due to progressive worsening of symptoms. Grossly, severe emaciation and a massive enlargement of one mesenteric lymph node were found. Microscopically, a neoplastic round cell population with morphologic characteristics of mature lymphocytes infiltrated the mesenteric lymph node as well as the jejunal mucosa and exhibited a marked invasion of the mucosal epithelial layer. Immunohistochemically, the majority of cells expressed CD3, but not CD79α, indicating a T-cell origin of the tumor cells. Microscopic as well as immunohistochemical findings enabled the diagnosis of an epitheliotropic intestinal T-cell lymphoma, a neoplasm that has yet not been described in a harbor seal.

Primary central nervous system T-cell lymphoma in a common dolphin (Delphinus delphis)

This report describes the pathological findings in an adult female short-beaked common dolphin (Delphinus delphis) stranded alive in the Canary Islands. Necropsy examination revealed the presence of a nodular neoplastic growth in the central nervous system (CNS) at the level of the thalamus. Microscopical examination revealed the mass to be a lymphoma and immunohistochemical labelling demonstrated a T-cell origin. No significant lesions were observed in other organs, including lymphoid organs. This is the first report of a primary T-cell lymphoma in the CNS in cetaceans.

Clinical and pathologic characteristics of T-cell lymphoma with a leukemic phase in a raccoon dog (Nyctereutes procyonoides)

A 7.5-year-old raccoon dog (Nyctereutes procyonoides) from the Henry Doorly Zoo (Omaha, Nebraska) presented to the veterinary hospital for lethargy and weight loss. On physical examination, splenomegaly and hepatomegaly were noted on palpation and were confirmed by radiographic evaluation. Radiography also demonstrated a mass in the cranial mediastinum. A complete blood cell count revealed marked leukocytosis (115,200 cells/µl), with a predominance of lymphoid cells. The animal was euthanized due to a poor prognosis. Necropsy revealed splenomegaly, hepatomegaly, and a large multiloculated mass in the cranial mediastinum. The histologic and immunohistochemical diagnosis was multicentric T-cell lymphoma with a leukemic phase.

Polyomavirus infection in a free-ranging California sea lion (Zalophus californianus) with intestinal T-cell lymphoma

An adult female California sea lion (Zalophus californianus) that stranded in central California was found to have a small glossal polypoid mass on gross necropsy. Histologically, the mass was consistent with a fibropapilloma, and intranuclear inclusions were found within endothelial cells lining small arterioles within the mass. Electron microscopy revealed 40-nm virions within endothelial intranuclear inclusions. Rolling circle amplification was used to obtain a partial viral genomic sequence. Sequence analysis identified the virus as a novel polyomavirus, tentatively named California sea lion polyomavirus 1. In addition, the sea lion had a severely thickened small intestine and swollen pale kidneys on gross examination. Severe renal amyloidosis with chronic interstitial nephritis was diagnosed histologically as well as T-cell intestinal lymphoma, which was confirmed via immunophenotyping and molecular clonality. The relationship, if any, between polyomavirus infection and the other disease processes in this sea lion is not known, but it is considered unlikely that the polyomavirus induced the lymphoma.