Comparison of Socio-demographic Characteristics, Tumour Features, and Surgical Treatment Outcomes in Phenotypic Variants of Basal Cell Carcinoma

Basal cell carcinoma (BCC) cases exhibit variations in tumour number, location, and growth patterns. While some patients develop only one BCC, approximately one-third of patients later develop one or more additional lesions. The aim of the study was to identify risk factors for further BCC lesions in patients with different phenotypic presentations. We retrospectively evaluated 1052 histopathologically diagnosed tumours of 861 patients, who were divided into four phenotypic presentation groups according to tumour number at initial diagnosis and during follow-up. Age, sex, tumour characteristics, surgical margins, re-excision and residual tumour rates were compared. Univariate and multivariate logistic regression analyses were performed to determine risk factors for multiple tumour development. There were 723 patients in the single presentation phenotype 1 (SPP1) group, 19 in the SPP-more group, 114 in the multiple presentation phenotype (MPP)-cluster initial group, and five patients in the MPP-cluster later group. Male sex was more common in the MPP-cluster later group ( = 0.028). The mean age was lower in the SPP1 and SPP-more groups ( = 0.002). Ear involvement was more common in the MPP-cluster later group ( < 0.05). Superficial and basosquamous subtypes were more common in the SPP-more and MPP-cluster later groups ( < 0.05). Re-excision and residual tumour rates were lowest in the SPP1 group ( < 0.05). Age over 69 years, male sex, and periorbital or upper extremity location were significant risk factors for multiple tumour development ( < 0.05). The limitations of our study include the inability to evaluate environmental risk factors, phenotypic and ethnic characteristics, and the short follow-up period for newly added patients. Predicting different phenotypic presentations by taking the age, gender, and tumour characteristics (localization, histopathological subtype) of the patients into account may allow new tumours to be detected at an early stage.