SIGNIFICANCE OF PREEXISTENT CONDITIONS IN BASAL-CELL CARCINOMA ON THELOWER-EXTREMITIES

Background. Basal cell carcinoma (BCC) rarely appears on the lower ext remities; over 85% appear on the head and neck. Case Reports. Five pat ients had BCC on the lower extremity. Histologically, this was of the superficial type. One patient developed a lesion of actinic keratosis. Results. The presence of pre-existent cutaneous changes of BCC arisin g on the lower extremities was studied. Among 40 tumors reported in Ja pan, 10 cases (25%) had pre-existent cutaneous changes. This value is significantly higher than those of BCC over the whole body in both Jap anese and Caucasian. Conclusions. Pre-existent cutaneous changes, thus , are thought to be a possible etiologic factor in the pathogenesis of BCC on the lower extremities.