Frontal mucocele presenting as a subcutaneous tumour on the forehead

A 57-year-old Japanese woman had a 3-month history of an asymptomatic subcutaneous tumour on the forehead. The patient presented a slightly elevated, elastic soft subcutaneous mass, 3 cm in diameter, on the mid to left-side forehead. Slight swelling of the left upper eyelid was observed. CT scanning and magnetic resonance images revealed a sharply demarcated cystic mass from the subcutaneous area on the forehead expanding into the frontal sinus and intracranial space. The tumour was diagnosed as a frontal mucocele and combined external and endoscopic approaches were performed. It is rare that a patient with a frontal mucocele is initially referred as a case of a subcutaneous tumour because most of the patients complain primarily of the ophthalmic symptoms. However, the present case reminds us that frontal mucocele is one of the differential diagnoses for a subcutaneous mass on the forehead.