[Pigmented spindle cell nevus and pigmented Spitz nevus--clinical and histopathological study on pigmented Spitz nevus, and its differentiation from early melanoma by fluorescence method and measurement of 5-S-CD level in the lesion].

On the basis of clinical and histopathological studies on 17 patients who had been diagnosed as having pigmented Spitz nevus (PSN), pigmented spindle cell nevus (PSCN) was surmised to be a type of pigmented Spitz nevus. In order to distinguish pigmented spindle cell nevus and pigmented Spitz nevus from early melanoma, 5 PSCN cases and 12 PSN cases were analyzed by the fine-needle aspiration fluorescence method, touch fluorescence method and measurement of the 5-S-CD level in the lesion. With the touch fluorescence method, fluorescent tumor cells were detected in one case of PSN. With the fine-needle aspiration fluorescence method, fluorescent tumor cells were detected in one PSCN case and 2 PSN cases. In comparison with fluorescent melanoma cells, the detected fluorescent tumor cells were smaller in size and number and resembled melanocytes. The 5-S-CD level in the lesion was 50 ng/mg or less in all cases, whereas the level in melanoma is known to be a high 100 ng/mg or more. In the final analysis, measurement of the 5-S-CD level in the lesion was concluded to have the greatest utility for differential diagnosis of pigmented spindle cell nevus and pigmented Spitz nevus from early melanoma.