Malignant transformation in an anal condyloma acuminatum.

A 61-year-old man had malignant transformation of an anal condyloma acuminatum, demonstrated by light and electron microscopic studies. Intranuclear virus-like particles were seen in the benign condylomatous koilocytotic cells but these were absent in the malignant cells. Multinucleation, syncytial giant cells and nuclear atypia in a condyloma acuminatum are considered features of in-situ carcinomatous change. Anal condyloma acuminatum requires wide excision and thorough examination of anorectal canal in order to exclude hidden disease, which will predispose to recurrence. Homosexuality is considered a predisposing factor. The authors stress the importance of histopathologic examination of all anorectal warts to exclude malignant change.