Carcinoma arising in a perianal sinus tract: report of a case.

The case of a woman who had had a perianal sinus tract for nine years, in whom squamous-cell carcinoma arose in the sinus tract, is presented. We believe that long-standing perianal sinus tracts should be examined carefully for tumor development. In suspected cases, a biopsy specimen should be obtained from the central part of the lesion.