Sinonasal malignant melanoma is rare and usually occurs in the nasal cavity. Presentation is often varied and occurs late in the natural history of the disease, resulting in a poor prognosis. A case is reported of a patient with malignant melanoma arising from the frontal sinus who presented with a forehead swelling and progressive confusion. A review of the literature on malignant melanoma in the nasal cavity and paranasal sinuses regarding its presentation, site of origin and principles of management is discussed.