Distribution and arrangement of multiple lesions in the anogenital region.

A series of skin diseases may affect the anogenital region with unusual presentations; therefore, a careful clinical approach is needed to make a correct diagnosis. Diseases of the anogenital area include inflammatory dermatoses, infectious lesions, and neoplastic conditions. Inflammatory dermatoses are frequently not restricted to the anogenital area and often occur on other sites. Infectious anogenital lesions can be easily confused with other benign or malignant processes. Tumors that arise on the anogenital skin are similar to those that occur on the skin elsewhere. The differential diagnosis of all of these lesions often depends upon the distribution and arrangement of the skin lesions.