Malignant peripheral nerve sheath tumour in the liver of a dog.

Summary A 14-year-old male mixed breed dog was presented for abdominal distension and abdominal pain. Radiographical examination identified a large space-occupying mass in the abdomen. Necropsy examination revealed the presence of a 12 cm hepatic mass that occupied almost half of the abdominal cavity. Microscopically, this mass consisted of spindle-shaped neoplastic cells that were arranged in short streams and interlacing bundles. Immunohistochemically, the neoplastic cells expressed vimentin, S-100, protein gene product 9.5 and neuron specific enolase, but were negative for cytokeratin, smooth muscle actin, melan A and von Willebrand Factor. These findings indicated that the hepatic mass was a primary hepatic peripheral nerve sheath tumour. To our knowledge, this is the first documentation of a primary hepatic malignant peripheral nerve sheath tumour in a dog.