A large helmet-shaped proliferating trichilemmal tumor of the scalp: Is definitive radiotherapy the treatment? A case report.

BACKGROUND: Benign proliferating trichilemmal tumors (PTTs) are a rare entity that arises from the outer root sheath of a hair follicle. They range from a benign PTT that recurs locally to the more aggressive malignant PTT that, in addition to recurring locally, has the potential for metastatic spread. However, as a group, PTTs are slow growing and amenable to surgery. To the best of our knowledge, radical radiotherapy without surgery has been used in only one case in an elderly male patient with good oncological and cosmetic results.

CASE PRESENTATION: We present a case of a young unmarried female with a disfiguring PTT of the scalp not amenable to surgery treated successfully with radiotherapy providing good cosmesis. Volumetric modulated arc therapy was used to treat this patient with a dose of 50 Gy in 25 fractions over 5 weeks. A theoretical risk of malignant transformation was explained to the patient. The patient has maintained good cosmesis over the last 12 months with no signs of re-growth.

CONCLUSION: In patients with PTT not amenable to surgery, radiotherapy may be an effective alternative providing local control and good cosmesis.