Introduction: We report a case in which multidisciplinary treatment including palliative radiotherapy reduced the size, exudate production and symptoms of a sebaceous carcinoma that had been neglected and allowed to form into a large destructive lesion. Case: A 48-year-old unemployed man who lived alone, was estranged from his family and socially isolated presented with a cranial tumor which had been present for three years. He did seek medical attention on one occasion. But a definitive diagnosis was not made, and he neglected to seek further treatment. The tumor became very large, painful and began to ooze exudate, and the patient became unwell with difficulty mobilizing. He was transported to the hospital by ambulance. The tumor was centered on the vertex of the scalp and had a maximum diameter of 30 cm. It was diagnosed pathologically as a sebaceous carcinoma and was inoperable. The tumor was treated with palliative radiotherapy, a total dose of 27 Gy　　/　　9 Fr, causing it to shrink by approximately 30% and markedly reduced the rate of exudate production. His condition improved markedly and he was able to go out on leave. Discussion: This case highlights the management and clinical course of an uncommon and large cranial sebaceous carcinoma.