Keratoacanthoma in the perianal area has been twice observed by the authors, while only once documented elsewhere. Its apparent infrequency in this location could be due to failure to recognize it. The endeavor to differentiate between this benign entity and true squamous cell carcinoma should be kept up to prevent unwarranted mutilating surgery. A retrospective review of former perianal epithelioma series, should also be undertaken to determine the actual cure rates for the malignant lesions.
ELLIOTT GB, FISHER BK. Perianal Keratoacanthoma. Arch Dermatol. 1967;95(1):81-82. doi:10.1001/archderm.1967.01600310087020