Comparision of histological types of primary and subsequent relapsing basal cell carcinomas of the skin.

BACKGROUND Basal cell carcinoma (BCC) recurrences are relatively frequent event in a routine dermatologic practice. One of the most important factor which impacts risk of their development is a histomorphological appearance of tumor. DESIGN The purpose of our study was to compare histological types of primary and corresponding relapsing BCCs of the skin. MATERIAL AND METHODS The study included 36 cases of BCC recurrences from 34 patients, 17 women and 17 men. The patients ranged in age from 32 to 97 years, with a mean age of 67.1 years at the time of (the first) recurrence. RESULTS Both tumor groups generally exhibited the same proportion of indolent and aggressive histological phenotype. In 21 cases (58.4%), we found an identical histological BCC type in primary and subsequent relapsing lesion. In 3 cases (8.3%), primary lesion showed indolent histological features without aggressive--growth component, while recurrent tumor already manifested it. Conversely, in next 3 cases (8.3%) primary tumor exhibited focal infiltrative-growth features and corresponding relapsing lesion did not. Of the remaining 9 cases (25%), histomorphological phenotype was not identical, but it showed the same prognostic histological tumor variant. CONCLUSION Based on the results of our study it can be assumed that a BCC recurrence is a dynamic histogenetic process, during which the phenotypic transformation and the changes in histomorphological picture of lesions occur, probably as a result of the interactions between cancer cells and re-modulated surrounding stroma.