Ormsby and Montgomery

 
"The histopathologic changes [in melanoma] are concerned with malignant metaplasia of the ordinary nevus cell . . . Most investigators are agreed that when a nevus undergoes malignant change the earliest changes, in the majority of the cases, are seen in nevus cells at the epidermal cutis junction. Exceptionally, the first malignant changes are seen in nevus cells deep in the cutis, in the so-called subdermal type of nevus. The nevus cells increase in size, and usually there is an increase in melanin pigment and the dopa reaction is definite and positive. The proportion of the nucleus to the cytoplasm is increased. A varying number of mitotic figures are seen, the cells usually proliferate into the cutis in an alveolar-like arrangement. Early invasion of the lymph and blood vessels occurs, so that metastasis may result through either system. Destruction of elastic tissue and dermal appendages in the path of the growth of the tumor occurs. As the cells invade the cutis, they seem to lose their ability to form pigment." (Fig. 2) Ormsby OS, Montgomery H. Diseases of the skin. 7th edition. Philadelphia: Lea and Febiger, 1948:844.

View Figure  		Fig. 2   Our diagnosis and comment: Melanoma. This so-called early melanoma is at least several years old, there is no evidence of a mole (melanocytic nevus) in this photomicrograph, and the "malignant nevus cells" are actually neoplastic melanocytes of melanoma. Parenthetically, what conventionally are called "nevus cells" are really abnormal melanocytes of a nevus.
 

Brief Critique

 
There is nothing in these lines that permits a histopathologist to arrive at a diagnosis of melanoma. Nary a single criterion requisite for that diagnosis is proposed. Furthermore, much that is written is wrong, such as the concepts of nevus cell, nevus undergoing malignant change, and cells of melanoma losing capability for producing melanin as they descend progressively into the dermis. A so-called nevus cell, nevocyte, or nevomelanocyte is an abnormal melanocyte. It qualifies as a melanocyte because it has capability for manufacturing melanin. As a rule, melanocytes of a melanocytic nevus do not transform into melanocytes of melanoma. Even when a melanoma develops in continuity with a nevus, such as Clark's nevus, it seems to originate from melanocytes other than those of the nevus itself. Last, melanocytes at the base of a melanoma sometimes produce much more melanin than those at the surface of it.