Penile fibrosarcoma tumor in a bull

This is a report of a penile fibrosarcoma in a two-year-old crossbred Holstein bull. The ulcerated tumor mass with dimensions of 7 × 9 × 6.5 cm, was enveloped the glans and body of the penis. It had a white-gray color at cross section appearance. There was no metastatic evidence of regional lymph node enlargement. Histopathologically, elongated spindle-shaped cells arranged densely in the interwoven pattern had a low rate of mitosis with oddly-shaped nuclei and pleomorphism. Immunohistochemically, the neoplastic cells were positive for vimentin and S100, but negative for α-smooth muscle actin, desmin, C-KIT and GFAP.