Melanoma In Situ Versus Melanocytic Hyperplasia in Sun-damaged Skin

Abstract

For differentiation of melanoma in situ (MIS) from melanocytic hyperplasia (MH) in sun-damaged skin, several criteria have been proposed. To assess sensitivity and specificity of those criteria, we examined the epidermis adjacent to 50 consecutive basal cell carcinomas and 50 MISs in skin with significant solar elastosis. The most valuable criteria for the diagnosis of MIS, as opposed to MH, were presence of nests of melanocytes, irregular distribution of melanocytes, descent of melanocytes far down adnexal epithelial structures, irregular distribution of pigment, presence of melanocytes above the junction, a high number of melanocytes, pleomorphism of melanocytes, and atypical nuclei of melanocytes. Other criteria, e.g., collapse of cytoplasm around nuclei of melanocytes; flattening of rete ridges; differences in the area, shape, and contour of nuclei of melanocytes as assessed by nuclear morphometry; and presence of melanocytes stained by HMB-45 and Ki-67/MIB-1 monoclonal antibodies, were found to be of low or no value for differential diagnosis.

Use of Digital Epiluminescence Microscopy to Help Define the Edge of Lentigo Maligna

“…The presence of melanocytic nests, nonuniform distribution of melanocytes, melanocytes far down the adnexal structures, melanocytes above the dermoepidermal junction, and melanocytic atypia defined melanoma in situ. 9 Furthermore, the nests contained at least 3 atypical melanocytes. The nonuniform pigmentation of cells along the basement membrane was interpreted as crowding.…”

“…The criteria used for the diagnosis of a positive or negative margin were those established by Weyers et al 9 for the diagnosis of melanoma in situ. The presence of melanocytic nests, nonuniform distribution of melanocytes, melanocytes far down the adnexal structures, melanocytes above the dermoepidermal junction, and melanocytic atypia defined melanoma in situ.…”

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

“…The more distinctive changes of melanoma, for example, presence of melanocytes above the dermoepidermal junction, formation of nests, or even dense collections of contiguous melanocytes, may not be present in all melanomas and may not be present in all portions of any given melanoma 6 . Because sun‐damaged skin may also focally possess some of these features, evaluation of the surgical margins of MIS can be challenging 6 . Dubow and Ackerman, 7 Maize and Ackerman, 8 and Acker and colleagues 9 have provided criteria to help differentiate MIS from sun‐damaged skin.…”

Management of lentigo maligna and lentigo maligna melanoma: Seminars in surgical oncology

“…Multinucleated and giant cell forms may be present. Dendritic melanocyte processes are considered highly specific for the diagnosis of LM [25]. Epithelioid melanocytes with pagetoid distribution are not characteristic of LM.…”

“…Solar melanocytosis is characterized by evenly distributed, single cell junctional melanocytic hyperplasia, with no evidence of contiguous growth, nesting, suprabasilar spread, or significant adnexal extension [31]. The most important criterium for the diagnosis of LM is the presence of nesting, defined as aggregates of at least three melanocytes [25]. Benign junctional melanocytic nevi are exceedingly rare on sun-damaged skin of the elderly, therefore the presence of junctional nests, in association with single cell melanocytic hyperplasia overlying solar elastosis, is essentially diagnostic of LM in this age group.…”