A violanceous erosive-elevated lesion, 16×14×8mm, occurring on the left thigh in a 20-year-old man (case 1) and a blackish erosive-raised lesion, 16×15×10mm, arising on the right lower jaw in a 31-year-old man (case 2) were examined by HPLC measurement of 5-S-Cysteinyldopa (5-S-CD) levels in gauze exudates and by the touch fluorescence method from the surface of the lesions. As a large number of fluorescent melanoma cells were observed under the fluorescence microscopy, and 5-S-CD values showed high level in gauze exudates in both 2 cases, the definite diagnosis of malignant melanoma was made before operation. Pathological findings showed superficial spreading melanoma, stage III, pT4aN1M0 in case 1, and nodular melanoma, stage III, pT4aN1M0 in case 2, respectively. The fluorescent melanoma cells in unstained formalin-fixed paraffin-embedded specimen were classified into 5 types.These types of cells, except for round (epithelioid) cells, were positive for HMB-45 immunostaining. From these results, it is confirmed that the findings of the touchfluorescence method and the measurement of 5-S-CD levels in gauze exudates areuseful for the preoperative diagnosis of malignant melanoma, and that the observationof unstained specimen under the fluorescence microscopy is a simple and valuablemethod for demonstrating the melanogenic activities in melanoma cells, which areverified by the positive findings of HMB-45 immunostaining.
