A Comparative Study of Fluorescence in Malignant Melanoma and Nevocellular Nevus Using a Fluorescence Microscope and Formalin‐fixed Specimens

Fluorescence in malignant melanoma cells was investigated. The specimens from 18 cases of malignant melanoma and 26 cases of nevocellular nevus, which were fixed with formalin and embedded in paraffin wax, were studied by the fluorescence microscopic method. On the fluorescence microscope, the malignant melanoma cells emitted intense fluorescence from the cytoplasm. The nevus cells with large amounts of melanin granules showed moderate fluorescence. The tumor cells of melanoma in situ and nevus cells with few melanin granules emitted little fluorescence. Not only malignant melanoma cells but also nevus cells in the formalin fixed specimens had various degrees of fluorescence. Many cases of malignant melanoma emitted intense fluorescence, but this was rarely found in nevocellular nevus. This method is also useful in differentiating melanoma from nevocellular nevus.