Pagetoid malignant melanoma and lentigo maligna melanoma of toe. A study with the fluorescence method (Falck and Hillarp).

Two cases of malignant melanoma on the toe of middle-aged women were examined chiefly by the fluorescence method of Falck and Hillarp. In one of the patients, histopathology of the pigmented tumor on the left middle toe was a Pagetoid (superficial spreading) melanoma in situ, and the subungual granulomatous lesion on the right great toe in the other patient was a lentigo maligna melanoma. On fluorescence microscopy, characteristic findings of the pigment cells lying in the epidermis of both types may be summarized as follows: In the Pagetoid melanoma, the melanoma cells are ovoid, lack dendritic processes, and emit specific yellow fluorescence. In the lentigo maligna melanoma, the pigment cells clearly show dendritic processes, and emit specific green fluorescence.