Widespread metastasis of a spermatocytic seminoma with concomitant hepatic peliosis in a Southern African hedgehog ( Atelerix frontalis )

Abstract

A six-year-old intact male Southern African hedgehog (Atelerix frontalis) presented with a history of chronic mild to moderate weight loss, and sub-acute hind limb ataxia that progressed to complete paralysis, at which point the hedgehog was euthanised. At autopsy, a large multinodular pale mass had completely replaced the left testicle and transcoelomically metastasised to the diaphragm and the peri-renal area, from where it then invaded the vertebral column and spinal cord. Multifocal, irregular to round, well-demarcated, blood-filled, proliferative lesions were also present in the hepatic parenchyma. Histological analysis of both the testis and metastatic lesions revealed diffuse sheets of neoplastic cells with moderate pale cytoplasm, large irregular to round nuclei and mostly one prominent magenta nucleolus, consistent with metastatic seminoma. The neoplastic cells were negative for periodic acid-Schiff (PAS) stain and positive for CD117 by immunohistochemistry (IHC). Taken together with the morphology of the neoplastic cells and the advanced age of the animal, this is suggestive of a spermatocytic seminoma. Histological analysis of the liver revealed multifocal lesions consisting of large anastomosing blood-filled spaces bordered by compressed hepatocytes, consistent with hepatic peliosis. This is the first report of a neoplasm in the Southern African hedgehog (Atelerix frontalis), the first report of a metastatic seminoma in a hedgehog, together with diagnosis of spermatocytic subtype, and the first report of a hedgehog with concomitant hepatic peliosis.