Percival, Montgomery, and Dodds

 
"The following criteria indicate malignant nature of the tumour [melanoma]: frequent and atypical mitoses, the overall large size of the cells and their lack of uniformity, large hyperchromatic nuclei, fusion of cells. Large amounts of pigment in the lesion, invasion of the epidermis by tumour cells, marked junctional activity at the periphery of the lesion, and a marked lymphocytic reaction in the surrounding dermis." Percival GH, Montgomery GL, Dodds TC. Atlas of histopathology of the skin. 2nd Edition. Maryland: The Williams and Wilkins Co., 1962:406.
 

Brief Critique

 
Of the criteria enumerated, only mitotic figures (some of them abnormal), nuclear atypia, and presence of melanocytes above the dermo-epidermal junction have merit in regard to specific diagnosis of melanoma. But none of them and all of them do not facilitate differentiation of melanoma from some examples of Spitz's nevus. Some precepts of the authors are without merit for specific diagnosis of melanoma, among them fusion of cells, abundant pigment, and junctional activity.