Fatal splenic rupture caused by an atypical malignant lymphoma in a Holstein cow

Postmortem examination of a 5.5-year-old Holstein cow with history of sudden death showed a very huge spleen (120 × 45 × 10 cm) associated with severe haemoperitoneum. Histopathological findings included extensive infiltration of medium to large sized lymphocytic and lymphoblastic cells with small amounts of cytoplasm, round nuclei with coarsely granular chromatin in the spleen, and limited foci of similar cellular infiltration in the liver. This case was diagnosed as a fatal splenic rupture caused by an atypical malignant lymphoma.