[Heterotopic cloacogenic carcinoma of the lower lip]

Cloacogenic carcinoma is a tumour which develops from cylindric epithelial cells at the anorectal junction. Besides this usual localization, other sites have been described including the vagina, urethra, sigmoid colon, vulva and perianal skin. We observed a labial localization in a 50-year-old woman. A 15 mm tumorous formation developed rapidly after initial excision without skin or mucosal changes. The clinical diagnosis was epidermoid carcinoma but histological examination revealed an aspect comparable to cloacogenic carcinoma with nodules of basaloid tumour cells showing atypical mitosis within the nodules and the uniformly eosinophilic masses. We considered that this particular histological aspect eliminated the diagnosis of basocellular or epidermoid carcinoma and suggest that the carcinoma developed from embryon reliquats of cloacoanal transition cells in a heterotopic localization.