Malignant Proliferating Trichilemmal Tumor of the Scalp: A Systematic Review

Malignant proliferating trichilemmal tumors of the scalp can exhibit aggressive presentation and recurrences. Our objective was to perform an evidence-based systematic review evaluating clinical presentation, tumor characteristics, and treatment modalities used to determine which treatment strategies had the best outcomes.

The databases PubMed, Embase, and Cochrane Library were searched for relevant literature by the authors. Patient demographics, imaging, treatments, and other clinical characteristics were obtained. The results were reported using the Preferred Reporting Systems for Systematic Reviews and Meta-Analysis guidelines.

Thirty-nine studies with a total of 65 patients were identified. The most common presentation was a history of slow-growing, painless swollen mass on the scalp. In total, 10 patients (15.4%) presented with spread to the regional lymph nodes and 6 (9.2%) additional patients presented with metastasis to distant locations. In total, 61 patients (93.8%) underwent surgery. Various chemotherapy and radiation therapy regimens were used. Of the 45 cases with documented follow-up, 11 (24.4%) patients had one or multiple instances of local, lymph node or metastatic tumor recurrence.

Surgery is favored, and the exact approach should be based on clinical judgment. However, Mohs micrographic surgery should strongly be considered because of its superior margin control against such an invasive tumor. Radiotherapy and chemotherapy have been used as adjuvant therapy in aggressive cases or recurrence. Patients should be followed closely and examined often to frequently assess recurrence or metastasis. Randomized controlled trials are needed to further clarify these findings.