A 13-year old male Poodle dog was presented with a considerable disparity in the size of testes. Palpation demonstrated enlargement of the right testicle; smooth surface without any sign of nodular hyperplasia was detected. Both testes were removed, the enlarged one was sent to a histopathology laboratory. Microscopic examination revealed massive neoplastic proliferation of the testicular germ cell tumour (seminoma) and an accompanying smaller tumour originating from the interstitial Leydig cells (Leydigoma), which was confirmed by immunohistochemistry. Simultaneous occurrence of two different types of tumours in testes is possible, representing a multiple primary malignancy case, which is a rare phenomenon in veterinary practice.
Successful treatment of de novo multiple primary malignancy with long term favorable outcome