The Density and Distribution of Melanocytes Adjacent to Melanoma and Nonmelanoma Skin Cancers

Abstract

There is a high degree of variability in melanocyte densities seen adjacent to melanoma and nonmelanoma skin cancers. Contiguous melanocytes, atypical melanocytes, and follicular melanocytes can be seen in the sun-damaged skin surrounding both melanoma and nonmelanoma skin cancers, but especially with melanoma. Because some of the features of melanoma in situ can be seen in chronically sun-damaged skin, the Mohs surgeon should be cautious when assessing the margins for melanoma in this setting.

Clinicopathologic study of 85 cases of melanoma of the female genitalia

“…Atypical melanocytic hyperplasia (AMH), an increase in the density and size of pleomorphic melanocytes localized to the epidermis, 8,20 is traditionally thought to arise from chronically sun damaged skin 21,22 ; however, 15 of 36 patients described herein demonstrate AMH adjacent to melanoma of the female genital tract (see Fig 2). AMH has been documented on clinically normal-appearing mucosa of the genitalia in females with vulvar melanoma.…”

Efficacy of Imiquimod Cream, 5%, for Lentigo Maligna After Complete Excision

“…42 Although it has been argued that there is a risk of missing minor residual changes if reliance is placed on hematoxylin-eosin stains only without additional immunohistochemical stains, the use of melan-A has been shown to contribute to errors in the diagnosis of melanocytic lesions in sun-damaged skin tumors. 43,44 Therefore, immunostaining was not relied on for diagnosis of LM in this study.…”

Melanoma in situ

“…Criteria that support a diagnosis of MIS over melanocytic hyperplasia of sun-damaged skin include the presence of melanocytic nests, an irregular distribution of melanocytes, the descent of melanocytes along the adnexal structures, the presence of melanocytes above the dermoepidermal junction, an increased number of melanocytes, pleomorphism and atypia of melanocytes, and an irregular distribution of pigment. 6 However, these criteria are not fully reliable. 6,7 In everyday practice, these cases are difficult and challenging because of concern about the under-or overdiagnosis of MIS.…”

“…6 However, these criteria are not fully reliable. 6,7 In everyday practice, these cases are difficult and challenging because of concern about the under-or overdiagnosis of MIS. The ambiguous histopathology based on obtained biopsy specimens often mandates complete excision to establish a more definitive final diagnosis.…”

“…5 However, it is clear that there is a high degree of variability in melanocytic density. 6 Some attempts have been made to define criteria that would help differentiate MIS from melanocytic hyperplasia of sun-damaged skin. Criteria that support a diagnosis of MIS over melanocytic hyperplasia of sun-damaged skin include the presence of melanocytic nests, an irregular distribution of melanocytes, the descent of melanocytes along the adnexal structures, the presence of melanocytes above the dermoepidermal junction, an increased number of melanocytes, pleomorphism and atypia of melanocytes, and an irregular distribution of pigment.…”