A Case of Long-term Survival of a Patient with Eustachian Tube Mucosal Melanoma

Malignant melanoma, a highly aggressive cancer, originates from melanocytic cells. The skin is the most common primary site, with cases of the cancer arising from the mucosa accounting for about 9.5% of all cases. Mucosal melanoma most frequently arises in the sinonasal cavity, and primary onset in the eustachian tube is extremely rare. While the prognosis of mucosal melanoma is generally poor, we encountered a case of long-term survival following treatment with a combination of surgery and radiation therapy. A 50-year-old woman was admitted to our hospital with the complaints of left-sided otalgia and recurrent otitis media. Initial physical examination revealed a dark brownish tumor in the left pharyngeal orifice of the eustachian tube. Based on this finding and findings in the subsequent contrast-enhanced MRI and biopsy examinations, we diagnosed the patient as having stage III (cT3N0M0: UICC 8th edition) mucosal melanoma. We performed en-bloc resection of the eustachian tube via a transpalatal approach, followed by postoperative radiotherapy (60 Gy in 30 fractions). At present, 6 years after completion of the above treatment, the patient remains well, without any signs of recurrence. Herein, we report on the outcome of treatment of a patient with mucosal melanoma of the eustachian tube, along with a review of literature. Appropriate choice of treatment and an adequate incision margin at surgery might help in overcoming the unfavorable prognosis of mucosal melanoma.