当初メラノーシスと診断し経過観察を要した悪性黒色腫の1例

A Case Report of Nasal Malignant Melanoma, Initially Diagnosed as Melanosis

　はじめに

　悪性黒色腫は，メラノサイトから発生する悪性腫瘍で，メラノサイトが存在する部位のいずれからでも発生し得る。一般には皮膚原発のものが知られているが，鼻副鼻腔，口腔咽頭など粘膜に発生する悪性黒色腫は，皮膚原発のものに比べ予後不良である^1,2）。今回われわれは，当初病理組織学的にメラノーシスと診断され，経過観察中に悪性黒色腫と診断された1例を経験したので報告する。

A 67-year-old female presented with black col-ored discharge from the choana. The first histopath-ologic diagnosis of the mucosa in the nasal cavity was melanosis with no malignancy. We closelyobserved the patient regularly because of the possi-bility of nasal melanoma, and nine months later malignant melanoma was histopathologically diagnosed. She underwent lateral rhinotomy opera-tion for removal of melanoma followed by irradia-tion therapy of total 54.2 Gy. However, 18 months later, bone and liver metastases were found. Further 4 months later, she died because of liver malfunc-tion. Although it has never been reported that melanosis in the nasal cavity changed to malignant melanoma, melanosis can be changed to melanoma.