Basal cell carcinomas of the scalp after radiotherapy for tinea capitis: Clinicopathological study in a case series of 96 patients with analysis of 427 tumours

Abstract

Background/Objectives: Low-dose X-ray radiotherapy to treat tinea capitis during childhood is a well-known risk factor for scalp basal cell carcinomas (BCCs). Post-radiotherapy BCCs are often multiple, and it has been suggested that they display more aggressive features. Our main objective was to study the clinicopathological aspects of post-radiotherapy BCCs to evaluate their biological behaviour and identify features that may differ from other BCCs. Methods:We performed an observational, retrospective study assessing multiple clinical and pathological characteristics of patients with post-radiotherapy BCCs. Results:We studied 96 patients with 427 post-radiotherapy scalp BCCs. Postradiotherapy BCCs were often multiple (median of 4 lesions/patient, ranging from 1 to 54). Significant comorbidities included a high incidence of thyroid disease and meningiomas. Recurrences were observed in 23% of patients, but there may be confounding factors, such as referral bias, heterogenous treatment modalities and occurrence of new tumours due to field effect. We found a high incidence of infundibulocystic BCCs (in 14.6% of patients and corresponding to 5.4% of the total number of tumours), trichoblastomas (5.2%) and neurofibromas of the scalp (10%). Conclusions:This study is consistent with the occurrence of multiple lesions (sometimes numerous) and a relatively high tendency for recurrence in postradiotherapy BCCs, as suggested by previous studies. We also found a high incidence of the infundibulocystic variant and a higher risk of follicular tumours and neurofibromas, which suggests that radiotherapy may influence the type of differentiation of BCCs and contribute to induce neoplasms of different cell lines.