Hilar lymph node metastasis of amelanotic malignant melanoma of unknown origin

We report a case of hilar lymph node metastasis of amelanotic malignant melanoma of unknown origin. A left pulmonary nodule was detected during a check-up in a 58-year old woman. Chest computed tomography indicated a large left hilar mass located between the upper and lower lobes. She underwent left pneumonectomy with mediastinal lymph node dissection, and the tumour was diagnosed as hilar lymph node metastasis of an amelanotic malignant melanoma; however, the primary lesion could not be detected. Thus, the possibility of spontaneous regression of the primary lesion and the amelanotic subtype of malignant melanomas should be considered in clinical practice.