Malignant adnexal skin tumors: A 15-year case series analysis from a Latin-American institution

Malignant Adnexal Tumors of the Skin (MATS) are rare neoplasms that differentiate into adnexal structures, including hair follicles, sebaceous glands, and eccrine or apocrine glands. With an incidence of approximately 5 per 1 million person-years, there are no standardized guidelines for their diagnosis and treatment, leading to inconsistent outcomes. This study aims to describe the clinicopathological characteristics and outcomes in an oncology reference center over 15 years.

We retrospective analyzed 40 patients diagnosed with MATS at the National Cancer Institute of Mexico from 2005 to 2020. We collected clinical variables (age, gender, histological subtype, tumor site, and treatment) and pathological features (tumor size, lymphovascular invasion, perineural invasion, depth, necrosis, and margin status). We analyzed disease-free survival (DFS) and overall survival (OS).

The median age at diagnosis was 64 years, with a slight male predominance (55 %). Eccrine/apocrine tumors were the most common (57.5 %), followed by sebaceous (25 %) and follicular tumors (17.5 %). The head and neck were the most frequent sites (52.5 %). Surgical excision was performed in 95 % of patients, with adjuvant radiotherapy in 17.5 %. Lymph node metastases were present in 5 %, and no distant metastases were observed initially. Recurrence occurred in 17.5 % of patients. Median DFS was 45.3 months, and median OS was 48.9 months.

Radical excision remains the primary treatment for MATS, though adjuvant radiotherapy may be helpful in high-risk cases. Prospective studies are needed to establish treatment guidelines and to improve outcomes.