Clinical distribution patterns and histopathological features of 2016 cases of basal cell carcinoma: a retrospective study from Southwest China

BACKGROUND: To investigate the clinical distribution patterns and clinicopathological characteristics of basal cell carcinoma (BCC) in Southwest China. METHODS: A retrospective analysis was conducted among 2016 patients diagnosed with BCC between April 2003 and May 2025. The study focused on lesion locations, facial distribution patterns, presentations of multiple BCCs, and histopathological features of BCC. RESULTS: A total of 2016 patients with 2138 BCC lesions were included, comprising 881 males (43.70%) and 1135 females (56.30%). The median age at initial diagnosis was 65 years (range, 17-101 years). Only 70 (3.50%) patients were younger than 35 years, whereas 663 (32.89%) were older than 70 years. The incidence of BCC increased with age from the fifth to the eighth decade of life. Most lesions were located on the head/face (88.59%, 1894), and 80.64% (1724) occurred on the faces. The nose/perinasal area was the most common facial subregion (31.15%, 666), followed by the cheeks (20.91%), indicating a midface predilection. Clinically, nodular/ulcerative presentations predominated (65.20%, 1394). Histopathologically, the nodular cystic subtype was most common (71.94%, 1538). Multiple tumors (two to ten lesions) were observed in 36 patients, including three cases with basal cell nevus syndrome. Surgical resection was performed in 97.82% (1972) of patients, while Mohs micrographic surgery was used in 25 (1.24%) cases. The 5-year recurrence rate was 4.10%. CONCLUSIONS: BCC predominantly affects older adults, with an increasing incidence in those aged 50-80 years, and shows a striking predilection for sun-exposed midfacial sites. Nodular/ulcerative lesions are the predominant clinical presentation, and nodular cystic type is the most common histological subtype. Surgery remains the mainstay of treatment; although recurrences were infrequent, their distribution supports risk-adapted management and long-term follow-up.