T H E Relationship of Malignant Amelanotic Melanoma (naevocarcinoma) to Extramammary Paget’s Disease

Ever since Sir James Paget first described the disease of the nipple named after him and remarked that he had seen a lesion clinically resembling it on the glans penis, followed by cancer, reputed cases of extramammary Paget’s disease have been sporadically reported and their nature discussed. The debate has been ancillary to the related question of the nature of Paget’s disease, which is still not completely settled, although the great majority of writers now accept it as a malignant neoplasm and not a dyskeratosis which may only secondarily become neoplastic. In a recent very excellent analysis of 57 reported cases of extramammary Paget’s disease to which he added one more, Weiner rejected 32 , accepted 16 (including his own) without qualification, and thought 10 more were probably acceptable but had insufficient data to be sure. The accepted cases were all either in the axilla, on the vulva, or on the penis and scrotum. Moreover, many of them were associated with underlying glandular carcinomas or had some relationship with sweat or sebaceous glands. Weiner pointed out that the apocrine glands, which have a genetic relationship with the mammary glands, are found only in these regions, and he felt it proper to conclude that extramammary Paget’s disease does exist and that it is an intradermal metastasis from an underlying carcinoma of the apocrine sweat glands. After studying all of the case reports analyzed by Weiner and a few more which he failed to include, the writer is persuaded that his conclusions are well taken and that he has settled the question: Extramammary Paget’s disease does occur, and it consists of peculiar skin lesions which are clinically and microscopically similar to Paget’s disease of the nipple, are associated usually with an underlying apocrine sweat gland carcinoma, and are quite possibly secondary to it. What, then, are all the rejected cases of reputed extramammary Paget’s disease in other regions of the skin surface? Some of them are manifestly superficial basal-cell epitheliomas (the pagetoid epithelioma of the French), Bowen’s disease, or squamous-cell epithelioma, and do not conform either to the clinical or microscopical criteria of Paget’s disease. This, however, does not dispose of all the cases; there remain a handful of lesions having the skin manifestations of Paget’s disease, with or without other evidences of malignancy, occurring on parts of the body where there are no apocrine glands. An explanation of these cases has already been suggested, but as most of those making it thought that it explained all cases of extramammary Paget’s disease, the hypothesis has not received as much attention as it deserves. As long ago as 1911 Kreibich came to the conclusion that Paget cells qre ana-