Güllü Gencebay¹
Özlem Su Küçük²

¹Bezmialem University, Faculty of Medicine, Department of Dermatology and Venereology, İstanbul, Türkiye
²Bezmialem University, Faculty of Medicine, Department of Dermatology and Venereology, İstanbul, Türkiye

Gencebay G, Su Küçük Ö. Basal Cell Carcinoma. In: Kutlubay Z, editor. Guidelines in Dermatology. 1^st ed. Ankara: Türkiye Klinikleri; 2025. p.285-291.

ABSTRACT

Basal cell carcinoma (BCC) is the most prevalent non-melanoma skin cancer (NMSC) globally, with increasing incidence rates and healthcare costs, particularly in Europe and the U.S. Despite its high frequency, BCC rarely metastasizes or causes mortality. Its pathogenesis is largely associated with mutations in the Hedgehog (Hh) signaling pathway and the p53 suppressor gene. UV radiation, genetic predisposition, and factors like ionizing radiation, arsenic exposure, and immunosuppression (e.g., HIV infection or organ transplantation) significantly increase BCC risk. Certain genetic syndromes such as xeroderma pigmentosum, basal cell nevus syndrome, Bazex–Dupré–Christol syndrome, and Rombo syndrome can lead to early-onset BCC. Clinically, BCC is categorized into four major subtypes: nodular, superficial, morpheaform, and fibroepithelial (fibroepithelioma of Pinkus). Nodular BCC is the most common, presenting as pearly papules or nodules, often on the face. Dermoscopic features include arborizing vessels and blue-gray structures. Superficial BCC appears as erythematous, scaly macules or plaques, often on the trunk. Morpheaform BCC is more aggressive, presenting as scarlike plaques. Fibroepithelial BCC typically occurs on the lower back as a soft, skin-colored plaque. Non-invasive diagnostics, such as dermoscopy and reflectance confocal microscopy (RCM), enhance diagnostic accuracy. Dermoscopy offers 98.6% sensitivity and a diagnostic probability of 99%, identifying vascular, pigment-related, and non-pigmented structures. RCM improves specificity but is limited by cost and training requirements. Treatment primarily involves surgical excision, effective in over 95% of cases. Mohs micrographic surgery is reserved for high-risk, recurrent, or anatomically critical tumors. Recommended margins are 2-5 mm for low-risk BCC and 5-15 mm for high-risk cases. For tumors larger than 2 cm, margins of at least 13 mm may be necessary. Non-surgical treatments include radiotherapy, photodynamic therapy, topical agents (imiquimod, 5-fluorouracil), and targeted therapies like Hedgehog inhibitors (vismodegib, sonidegib). Cemiplimab, an immunotherapy, is approved for advanced BCC resistant to other treatments.Follow-up varies, with annual monitoring recommended for high-risk patients or those with multiple tumors.

Keywords: Non-melanoma skin cancer; Basal cell carcinoma; Pathogenesis; Staging; Treatment