Trichilemmal carcinoma in China: A case report and systematic literature review

Purpose: This study aimed to delineate the clinicopathological characteristics of trichilemmal carcinoma (TLC) in China, analyze its evolving epidemiological trends, and provide insights to improve clinical diagnosis and management through a comprehensive literature review and case-based analysis. Methods: A retrospective analysis of 40 years (1984-2023) was conducted by reviewing Chinese and English databases for TLC cases in Chinese populations. Data on epidemiology, clinical presentation, histopathology, treatment modalities, and prognosis were systematically collated, supplemented by a detailed case report to illustrate diagnostic and therapeutic challenges. Results: Among 230 documented cases, TLC exhibited a near-equal gender distribution (113 males, 117 females) and a rising incidence, with 50.43% (116/230) reported in the last decade (2014-2023). The patients showed a broad age distribution (20-97 years), with lesions predominantly concentrated in the head/neck region (87.83%, 202/230). Non-specific clinical features (papules, nodules, ulceration) contributed to frequent misdiagnosis. Metastasis (13 cases) and recurrence (14 cases), primarily in head/neck tumors, correlated with high mortality. Immunohistochemistry identified CK-H and EMA as key positive markers and S-100/CK-L as negative discriminators, with 23.91% (55/230) showing periodic acid-Schiff (PAS) positivity. Surgical excision was the primary treatment (87.39%), while adjuvant therapies (radiotherapy/chemotherapy) demonstrated limited efficacy. Conclusion: The increasing incidence of TLC in China, its anatomical predisposition to aggressive behavior, and poor prognosis in metastatic/recurrent cases necessitate improving early detection and optimizing treatment strategies for this rare malignancy.