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Dermatopathology: Practical & Conceptual January - March 2001
Evolution In Thinking: Criteria for Histopathologic Diagnosis of Melanoma, 1947–2000: A Critique in Historical Perspective
Mary Aldrene L. Tan, M.D.
A. Bernard Ackerman, M.D.
Becker and Obermayer
Ormsby and Montgomery
Percival, Montgomery, and Dodds
Pinkus and Mehregan
Clark and Mihm
Price, Rywlin, and Ackerman
Pinkus and Mehregan
Ackerman and Su
Kamino and Ackerman
Domonkos, Arnold, and Odom
Roses, Harris, and Ackerman
Okun, Edelstein, and Fisher
Weedon and Strutton
Elder and Elenitsas
Langley, Fitzpatrick, and Sober
Dewan and Ackerman
Farmer and Hood
"Superficial spreading melanoma, the most common subtype of malignant melanomas, histologically presents as a prominent intraepidermal proliferation of malignant melanocytes in a single-cell array throughout the epidermis. These cells resemble the cells of Paget's disease; hence the pattern is called pagetoid and the tumor is sometimes termed pagetoid melanoma. The pagetoid cells may spread up to and include the granular cell layer or may be confined to the lower portions of the epidermis. At times, two or more layers of the epidermis, including the basilar region, are replaced by these malignant cells."
"The cells have large cytoplasms [sic] that are round or ovoid (also called epithelioid) and that have round nuclei. The nuclei are large, have strikingly irregularly dispersed heterochromatin, especially around their margins, and possess nucleoli that usually stain pink. The nuclei vary in size, and multinucleate forms may be present. The cytoplasm has a finely granular texture and usually stains pink-tan. Mitotic figures occur among these intraepidermal cells. The epidermis itself is frequently hyperplastic but may be of normal thickness or atrophic."
"The radial growth phase of superficial spreading melanoma may be entirely intraepidermal (melanoma
or level I). More often, however, single cells or small clusters of cells similar in character to those in the intraepidermal component invade the dermis (level II). The papillary dermis may contain fibroplasia, a patchy or band-like lymphocytic infiltrate, occasional melanophages, and increased vascularity, especially in inflamed lesions. Mitoses may be noted among invasive dermal cells."
Fitzpatrick TB, Milton GW, Balch CM, Shaw HM, McCarthy WH, Sober AJ. Histopathology of malignant melanoma and its precursor lesions. In: Balch CM, Houghton AN.
2nd Edition. Philadelphia: JB Lippincott, 1992:2434.
The conjunction of pagetoid melanocytes and pagetoid pattern in the epidermis usually is indicative of melanoma, but, as stated in a previous "brief critique," most melanomas are devoid of pagetoid melanocytes. All of the other findings said to be characteristic of melanoma are seen commonly in Spitz's nevi.
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