A Case Report of Malignant Melanoma of the Sphenoid Sinus

Malignant melanoma of the sphenoid sinus is a very rare disease, and only 6 cases have previously been reported. The present case involved a 74-year-old woman who was examined for visual disturbance of the left eye. Computed tomography revealed a soft tissue shadow, but only mucosal hypertrophy was found on opening the sphenoid sinus under general anesthesia. One month postoperatively, visual disturbance of the right eye and paresis of cranial nerve III appeared. Malignant melanoma was diagnosed from biopsy. Multiple bone metastases were identified, but the patient declined active treatment. As a result, palliative care was provided and she died 3 months later. When there is no improvement in postoperative visual acuity as in this case, in consideration of the possibility of neoplastic lesions, rigorous followup including monitoring for neurological symptoms is warranted. 1. Introduction Almost 20% of melanomas (cutaneous and mucosal) originate in the head and neck, but only 1% arises from the sinonasal tract [1]. Malignant melanomas originating in the sphenoid sinus are extremely rare and only 6 cases have been reported previously [2–7]. We report the seventh case of melanoma arising from the sphenoid sinus. 2. Case Presentation The patient was a 74-year-old woman who was initially examined in neurosurgery for visual disturbance of the left eye. As computed tomography (CT) revealed a shadow in the sphenoid sinus, she was examined in the Department of Otolaryngology of Tokyo Medical University Hachioji Medical Center, revealing a polyp in the middle nasal meatus. Although a soft tissue shadow was observed in the left sphenoid sinus, no damage to the surrounding bone tissue was evident (Figure 1). Preoperative visual acuity was 0.03. No signs of cranial nerve paresis were observed. On the same day, the left sphenoid sinus was opened under general anesthesia using an endoscope. Figure 1: CT findings. The left sphenoid sinus shows a soft tissue shadow without bone damage. Mucosal hypertrophy was found, and the procedure was completed following removal of the mucosal lesion. Pathology specimens of the removed mucosal lesion were found to represent sinus mucosa with no neoplastic changes. As postoperative visual acuity only improved to 0.6, postoperative steroid therapy was initiated but did not improve vision. One month after surgery, visual disturbance of the right eye, headache, and ophthalmalgia appeared. Visual acuity was negative for light sense, and paresis of cranial nerve III was observed. CT showed soft tissue shadows in both sphenoid sinuses and