Basal cell carcinoma of unusual localization

Resumen

Abstract:
Background: 85 to 90% of basal cell carcinomas (BCC) are usually located on head and neck.
The presence of BCC in non-exposed areas is rare, and suggests the existence of still unknown etiologic factors.
Objectives: To analyze BCC’s anatomical distribution; to define usual/unusual sites for BCCs; to relate site and histopatological subtypes; to compare obtained data with national and
international literature.
Material and Methods: A retrospective study was performed. Patient data included sex and age at diagnosis; tumor data included histological subtype and anatomical site.
Results: 611 patients, 319 females. Mean age: 68,39 years. Total number of BCCs was 873. Body-site distribution was as follows: cephalic area 65,4%; trunk 20,7%. Less frequent localizations included
lower limbs 5% (leg 29, thigh 10, foot 3, knee 2); upper limbs 4,4% (arm 18, forearm 15, hand 15, palm 4); sacrolumbar area 2,7%; folds 0,8% (groin 3, popliteal area 1, axilla 2, interdigital feet fold
1); genitalia 0,6% (5); buttocks 0,3% (3). According to Lever’s histopathologic classification, the distribution of the above was: nodular 58,2%; partly nodular/infiltrative 19,9%; superficial 17,5%;
and infiltrative 4,5%.
Conclusions: Body site distribution in this series does not differ from others. More than 86% of
the tumors arose in head, neck and trunk. Statistically defined unusual sites are those anatomical location below 95 percentile (frequency less than 2%): abdomen, forearm, thigh, hand, scrotum, inguinal folds, buttocks, feet, vulva, axilla, knee, palm, popliteal fossae, interdigital feet fold.
Unusual site tumors summarize 36 lesions (4,12%). Nodular, partly nodular/infiltrative and infiltrative were predominant histological subtypes in head and neck, while superficial subtype was more frequent in trunk. Histological subtypes distribution did not show different patterns in less frequent anatomical sites.

(Dermatol Argent 2010;16(1):25-33).

Keywords: Basal cell carcinoma, anatomic site distribution, histological
subtypes.