Intravascular central nervous system T-cell lymphoma in a common dolphin (Delphinus delphis) with cerebral infarction.

Lymphoid and haematopoietic neoplasms are rare in cetaceans. This report describes intravascular lymphoma in an adult common dolphin that presented with neurological signs prior to stranding. Intravascular lymphoma is a rare neoplasm previously recorded in humans, dogs, a cat and a horse. The condition is characterized by intravascular neoplastic lymphocytic proliferation, the sequelae of which are dependent on the organ affected. Key pathological findings in this case included multifocal cerebrocortical malacia secondary to vascular occlusion associated with intravascular neoplastic lymphocytic proliferation. Immunohistochemistry supported a T-cell phenotype similar to that observed in dogs. The neurological presentation was consistent with that seen in other species in which the central nervous system is involved. The aetiology and pathogenesis have not been established in other species and although no further investigations were made in this common dolphin, this report adds to the short list of species affected by this rare neoplasm.