Mucosal malignant melanoma of the head and neck is a rare but aggressive type of melanoma with poor clinical prognosis and outcome. Its nonspecific symptomatology frequently leads to its delayed diagnosis until advanced stages of the disease. The author presents a case of primary sinonasal amelanotic melanoma with preoperative F-18 FDG PET/CT showing diffuse bone metastasis only two months after the onset of epistaxis and nasal congestion, and subsequent postsurgical CT/MR showing diffuse soft tissue tumor dissemination and malignant pleural effusion.