[Malignant transformation of perianal condyloma acuminatum]

A case of squamous cell carcinoma developing in a perianal condyloma acuminatum in a 38-year-old man treated for over 5 years with podophyllin is presented. Although there are many reports of malignant transformation of condyloma acuminatum in the skin and mucosal surfaces of the male and female genitalia, it is quite rare in the perianal region. In this case there were foci of carcinoma in-situ and of frank invasion, as well as areas of squamous cell carcinoma in the large perianal condyloma. The lesion was widely excised, and completely removed, and the site covered with a split-thickness graft from the thigh. Later, repeated dilatations of the anus were required. Repeated histologic examinations of condyloma acuminatum are needed to diagnose possible malignant transformation.