Primary Melanoma of the Skin and Cutaneous Melanomatous Metastases : Comparative Histologic Features and Immunophenotypes

Abstract

Through careful clinicopathologic correlation, we identified 37 metastatic melanomas in the skin, all of which had intraepidermal components. These were compared with 43 microscopically similar primary melanomas with a predetermined panel of immunostains in general use in surgical pathology, including bcl-2 protein, mutant p53 protein, Ki-67 (MIB-1), proliferating cell nuclear antigen (PCNA), alpha-isoform actin, and CD117 (c-kit protein). There was no significant difference in bcl-2 or alpha-isoform actin staining patterns of primary vs secondary cutaneous melanomas. The expression of Ki-67 generally was higher in metastatic melanomas than in primary lesions, and the same was true of mutant p53 protein labeling; however, some overlap was observed. CD117 staining was retained in 65% of metastatic melanomas (24/37) when they originated from ocular primary tumors; nevertheless, that marker was lost in virtually all of the other metastatic melanocytic neoplasms, whereas primary melanomas demonstrated consistent reactivity for c-kit protein. Although they are not definitive, these trends in immunoreactivity could facilitate the process of distinguishing the multiple primary melanoma syndrome from melanomatous metastases to the skin. That undertaking is best approached with circumspection, because clinicopathologic discriminators for this diagnostic separation are still imperfect.

Expression of c-Kit, p-ERK and cyclin D1 in malignant melanoma: An immunohistochemical study and analysis of prognostic value

“…In agreement with previous studies, the expression of c-Kit was highest in thin melanomas and decreased with tumor progression and metastasis [10][11][12][13][14][15][16]; furthermore, c-Kit expression had no significant impact on patient survival [17,18,[29][30][31]. Concerning the relationship with other clinicopathologic variables, c-Kit expression was only associated negatively with ulceration; it was not associated with either tumor subtype or tumor site in our study.…”

Second Primary Neoplasms in Patients With Uveal Melanoma: A SEER Database Analysis

“…Moreover, in our cohort all the identified cases of skin melanoma had available histologic confirmation in the SEER database. Considering their distinct pathologic and immunophenotypic features from skin metastasis of uveal melanoma, 34,35 misclassification is a very unlikely explanation for our findings.…”

A 92-gene cancer classifier predicts the site of origin for neuroendocrine tumors

“…Protein IHC has additional variation in antibody retrieval methods and antibody clone differences, as well as wide variation in techniques and controls used between labs; all these factors can all affect the rate of false positive and false negative IHC results. [68][69][70][71][72][73][74] In addition, selection of specific IHC markers and the interpretation of the protein expression patterns can be subjective and is dependent on the individual pathologist.…”