Aggressive fibromatosis of the spermatic cord. A typical lesion in a "new" location.

The authors describe a 31-year-old man with a 7 cm aggressive fibromatosis (desmoid tumor) of the spermatic cord presenting as a swelling in the left inguinal area that was excised along with the testis and cord. The desmoid tumor is histologically typical, but such tumors arising primarily from the paratesticular structures have apparently not been previously reported and the diagnosis would not be questioned if it not for the unusual site. This tumor is histologically and immunohistochemically indistinguishable from abdominal wall desmoid tumor, with or without Gardner's syndrome. Desmoid tumors at this location should be distinguished from reactive processes, such as pseudosarcomatous myofibroblastic proliferation (so-called "proliferative funiculitis") and inflammatory fibrous pseudotumor, all of which exhibit fibroblastic/myofibroblastic differentiation. Paratesticular fibrosarcoma and leiomyosarcoma should also be differentiated from desmoid tumor that does not have the metastatic potential of sarcomas. Thirty-four months post-operatively, an 8 cm local recurrence in the remaining portion of the left vas deferens causing left hydroureter and hydronephrosis was detected.