Cloacogenic carcinoma of the anal canal and associated viral lesions. An in situ hybridization study for human papilloma virus.

Five cases of cloacogenic carcinoma were analyzed for microscopic human papilloma virus (HPV)-induced changes and with in situ hybridization technique for HPV types 6/11, 16/18 and 31/35/51. Four of the five cases showed epithelial foci of koilocytotic atypia. HPV type 16/18 was present in four of the five cases. The surface epithelium in two of the four cases with koilocytotic changes showed HPV type 16/18. HPV type 6/11 was seen in surface epithelium in one case in which invasive carcinoma showed HPV type 16/18. This double infection with double morphologic expression could mean that the same behavioral pattern (anal intercourse) may contribute to both anal condyloma and carcinoma and, although patients with condyloma are at risk for carcinoma, condyloma may not be the precursor lesion in all cases with coexistent condyloma and carcinoma. Because of the similarity between pathogenesis of anal and cervical carcinomas, a periodic cytologic screening of anal mucosa could be indicated in populations at risk: homosexual men, patients with condyloma, women having dysplasia or carcinoma of the uterine cervix, and patients with immunosuppressive disorders.