DIFFERENCES IN AGE, SITE DISTRIBUTION, AND SEX BETWEEN NODULAR AND SUPERFICIAL BASAL-CELL CARCINOMAS INDICATE DIFFERENT TYPES OF TUMORS

Basal cell carcinomas (BCC) are among the most common cancers in white subjects. Etiologic factors include ultraviolet and ionizing radiatio n, chemical carcinogens, and possibly infection with human papillomavi ruses. Because of clinical and histologic differences, differential pa thogenetic mechanisms have been suggested for different BCC subtypes, We studied the patient and tumor characteristics of all BCC diagnosed and/or treated at the departments of Dermatology and Plastic Surgery o f our hospital between 1985 and 1996, and a review of the literature w as carried out. Some important differences between patients with nodul ar BCC and patients with superficial BCC were observed. The frequency of superficial BCC was higher in females and was seen in younger patie nts as compared with nodular BCC. The latter occurred mainly in the he ad/neck region: in males they were seen more frequently on the ears, a nd in females they were predominantly seen on the eyelids, the lips, a nd in the neck. Superficial BCC occurred mainly on the trunk, and occu rred significantly more often on the trunk in males than in females, w here the legs were the most common site. These findings strongly sugge st that the superficial subtype is a separate group within the clinica l entity of BCC, Furthermore, our findings seem to support the etiolog ic role of sun exposure in these tumors; however, this role may be dif ferent for each subtype, Chronic sun exposure may be an etiologic fact or in nodular BCC as compared with intermittent sun exposure in superf icial BCC, Other factors, such as differences in site specific host fa ctors and referral bias, may also play a role in the differences found between the subtypes.