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.

Department of Pathological Anatomy Faculty Hospital Zilina Slovak Republic