ASSESSMENT OF MORPHOLOGICAL PARAMETERS DEFINING RISK STRATIFICATION IN CUTANEOUS BASAL CELL CARCINOMA. A SINGLE-CENTRE STUDY

Abstract

Background: Basal cell carcinoma (BCC) is the most common skin malignancy worldwide, yet its clinical risk is heterogeneous and strongly influenced by histomorphological features. Data from Pakistan are limited, and local evidence is needed to inform treatment strategies based on histology-defined risk. Objective: To evaluate histomorphological parameters for risk stratification in cutaneous basal cell carcinoma in a Pakistani population. Study Design: Single-centre observational study. Setting: Department of Histopathology, Chughtai Lab, Pakistan. Duration of Study: 1 March 2023 to 30 September 2024. Methods: Histopathology reports of 382 unique BCC specimens were retrieved from the laboratory information system (Nexus Pro). Extracted variables included age, gender, anatomical site, and maximum tumor diameter. Histological subtypes were categorized as nodular, infiltrative, superficial, keratotic, adenoid, micronodular, or mixed. Depth of invasion was measured from the reconstructed epidermal surface to the deepest tumor nest and stratified into clinically relevant groups. Adverse features, including perineural invasion (PNI), lymphovascular invasion (LVI), and ulceration, were documented. High-risk histology was defined a priori as any infiltrative or micronodular component (pure or mixed). Descriptive statistics were performed in line with STROBE guidance. Results: The mean age was 63.11 ± 14.48 years; 50.5% were female, and 63.9% were ≥60 years. The majority of lesions arose on the head and neck. Nodular BCC was the most common pure subtype (62.3%), followed by infiltrative (19.9%) and superficial (7.9%); mixed subtypes constituted 7.3%. Depth of invasion was ≥7 mm in 52.4% of tumors, while 36.2% measured ≥20 mm clinically. Adverse features included PNI in 6.5%, LVI in 0.5%, and ulceration in 86.9%. Overall, 25.1% of cases were classified as high-risk and 74.9% as low-risk histology. Conclusion: Nodular BCC was the predominant subtype, but one in four tumors exhibited high-risk histology. A substantial proportion of lesions were large (≥20 mm) or deeply invasive (≥7 mm) at presentation. Morphology-based risk stratification is practical for routine reporting and can inform surgical margins, surveillance intensity, and multidisciplinary referral decisions. Early detection, particularly for head and neck lesions, may reduce the burden of advanced disease.