Dull pink globules were found within the epidermis in 65% of junctional, 75% of compound, and 25% of intradermal types of Spitz's nevi (the nevi of large spindle and/or epithelioid cells). These globules were PAS-positive, diastase-resistant and also were positive with the trichrome stain. Similar-appearing eosinophilic globules were noted in the epidermis in only 2% of malignant melanomas and in but 0.9% of ordinary melanocyte nevi. The globules in malignant melanomas and in ordinary melanocytic nevi were negative with PAS and trichrome stains. Therefore, the finding of PAS- and tri-chrome-positive eosinophilic globules within the epidermis is a helpful sign for histologic differentiation of Spitz's nevus from malignant melanoma.
The histologic differentiation of Spitz's nevus (the nevus of large spindle and/or epithelioid cells) from malignant melanoma is of utmost importance in dermatopathology. Most authors agree that no single histologic finding enables absolute differentiation of the benign neoplasm from the malignant one. One of us (HK), while reviewing a large series of melanocytic lesions, observed distinctive eosinophilic globules within the epidermis and the dermis of many specimens of Spitz's nevus. The microscopic appearance of these globules and their significance is the subject of this paper.