Proliferating trichilemmal tumors are a rare entity that usually arises in the scalp . It occurs commonly after the sixth decade of life [4, 5]. Due to its rarity, it is frequently misdiagnosed as squamous cell carcinoma or sebaceous cyst. The diagnosis is based on histopathology with PTT exhibiting broad bands of proliferating epithelial cells that either surround cystic areas or are interconnected and separated by a generally fibrous, but occasionally sclerosed or cellular stroma . Within the bands, smaller basaloid cells are seen palisading at the periphery; these cells enlarge and become more squamoid as they progress toward the center [4, 6,7,8]. Surgical excision with margins of at least 1 cm has been the treatment of choice for PTT. The rate of local recurrence in PTT after wide local excision was found to be 3.7% in a meta-analysis . Radiotherapy as a treatment modality has been used in the adjuvant or palliative setting. In our review of the literature, we found only one case report of a PTT treated with radical radiotherapy . In that case report, a 93-year-old male patient with a 5 cm (in the largest dimension) PTT was treated with 45 Gy of radiotherapy over 3 weeks with electrons. The patient had achieved a complete response at 6 months post radiotherapy and continued to have no recurrence at 2 years after treatment. In light of the larger volume of disease, as depicted in Fig. 2, we decided to treat with 50 Gy. In order to adequately cover the tumor, the photon-based VMAT plan (Table 1) required the irradiation of a portion of the brain. As such, we elected to treat at 2 Gy per fraction over 5 weeks, as opposed to the literature case, where they elected to use a hypofractionated approach of 3 Gy over 3 weeks. The patient tolerated our treatment well with only grade 1 dermatitis and conjunctivitis. The reactions settled within 2 weeks of completion of treatment. At 1 month post therapy, the patient had a satisfactory improvement in both pain and bleeding. The objective response was partial as per the response evaluation criteria in solid tumors (RECIST) v1.1 criteria. By 3 months, tumor regression with good cosmesis was achieved. Tumor regression continued 6 months after treatment. At the time of writing this case report, the residual disease continues to be stable with no progression in size or number of lesions. A theoretical risk of radiotherapy, and one that must be explained to all patients being offered treatment, is malignant degeneration of the tumor. PTTs exist on a spectrum, ranging from relatively benign, such as PTTs that may locally recur but that do not metastasis, to the more aggressive MPTTs that can have significant metastatic potential. In addition, malignant transformation of a PTT into a trichilemmal carcinoma or the development of a radiation-induced malignancy, such as squamous cell carcinoma, is possible and also needs to be discussed. The extent of the tumor, the age of the patient, the importance of cosmesis at the site of disease, and alternative treatments, such as surgery, will all factor into this discussion and the patient’s ultimate decision regarding therapy.