Primary malignant melanoma of the esophagus arising from a melanotic lesion: report of a case.

We herein report a case of primary esophageal malignant melanoma in which the development from a preceding benign melanotic lesion and the growing process of the tumor were chronologically observed by serial endoscopic examinations. Biopsy specimens repeatedly taken from the tumor failed to identify the presence of malignant melanoma. A positron emission tomography scan and gross changes of the tumor endoscopically observed were useful for detecting the presence of malignant transformation. The patient eventually died of generalized metastatic disease soon after undergoing an esophagectomy. An early diagnosis may therefore be crucial for improving the treatment outcome of esophageal malignant melanoma. Therefore, esophageal melanotic lesions should be carefully followed up even if biopsy specimens repeatedly show no malignancy.