Comprehensive Management of Trichilemmal Carcinoma of the Lower Leg in an Elderly Patient with Comorbidities: A Case Study on Integrated ALA-PDT and

Hu Chan ^1* Xiaojing Liu ¹ Mingshun Wu ¹ Caihe Liao ¹ Yan Zhao ¹ Mingyuan Xu ² Yongxian Lai ³ Guolong Zhang ¹

• ¹ Institute of Photomedicine, Shanghai Skin Disease Hospital.Tongji University School of Medicine, Shanghai, China
• ² Department of Dermatopathology, Shanghai Skin Disease Hospital, Tongji University School of Medicine, Shanghai, China
• ³ Department of Dermatologic Surgery, Shanghai Skin Disease Hospital, Tongji University School of Medicine, Shanghai, China

Trichilemmal carcinoma (TC), a rare malignancy originating from hair follicle cells, typically affects sun-exposed skin in older individuals and necessitates differential diagnosis from other skin carcinomas. Here, we present one case of trichilemmal carcinoma in a 92-year-old female, admitted to our hospital with a large exophytic red tumor on her right lower leg. Notably, the patient had a history of long-standing hypothyroidism and hypertension, indicating that she was unable to tolerate extensive excision. Histopathology showed outer root sheath hyperplasia with clear cell differentiation and keratinization, alongside increased atypical cells.Immunohistochemistry revealed CK7 and EMA positivity, confirming follicular origin, while negative CK10, CK18, CEA, CK20, and GCDFP-15 excluded other follicular tumors. A high Ki-67 (80%) indicated high proliferative activity, supporting the TC diagnosis. Treatment involved managing her underlying conditions, followed by ALA-PDT and surgical excision for the carcinoma. This case illustrates the challenges in managing trichilemmal carcinoma in elderly patients with multiple comorbidities, emphasizing the importance of a comprehensive approach to treatment.