Background: The pathogenesis of acquired melanocytic nevi (AMN) is still unclear, and the origin of nevus cells has not been clarified.
Objective: To analyze the clinical features and pathological types of AMN and identify the possible origin of nevus cells.
Methods: A retrospective study of 2929 cases of AMN was conducted, and 96 specimens of intradermal and junctional nevi were selected. Immunohistochemical assays were performed to detect the expression of basement membrane component receptor DDR-1 and the molecular markers on epidermal melanocytes, dermal stem cells (DSCs), and hair follicle stem cells.
Results: Junctional nevi and compound nevi were prone to occur on glabrous skin, such as the palms, soles, and vulva, and on the extremities in children, whereas intradermal nevi tended to develop on the trunk, head, and face of adults. The immunohistochemical data revealed that both junctional nevi and intradermal nevi expressed the epidermal melanocyte surface markers E-cadherin, DDR-1, and integrin α6 and the DSC molecular markers NGFRp-75 and nestin. CD34 was expressed only in junctional nevi, whereas K19 was not expressed in any type of melanocytic nevi. There was no significant difference in molecular expression at different sites or in different ages of onset. Nestin expression was markedly stronger in the intradermal nevi than in the junctional nevi, but there was no difference between the superficial and deep nevus cell nests of intradermal nevi.
Conclusion: AMN may have a multicellular origin that commonly follows the mode of Abtropfung. Furthermore, DSCs may partly or independently participate in the formation of nevus cells.
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http://dx.doi.org/10.1097/DAD.0000000000001599 | DOI Listing |
J Cutan Pathol
November 2024
Department of Pathology, University of Arkansas for Medical Science, Little Rock, Arkansas, USA.
Background: Melanocytic tumors with perineuriomatous differentiation may pose diagnostic challenges. This study explores characteristics of perineuriomatous melanocytic nevi, an entity merging features of perineurioma and melanocytic nevi. The aim is to elucidate histopathological features of perineuriomatous nevi to allow dermatopathologists to recognize them and differentiate them from other spindle cell lesions.
View Article and Find Full Text PDFPathology
September 2024
Department of Pathology, Hospital Clínico Universitario, INCLIVA Biomedical Research Institute, Valencia, Spain; Department of Pathology, University of Valencia Avenida Blasco Ibáñez, Spain. Electronic address:
Large nested melanomas (LNMs) are a rare subtype of naevoid melanoma consisting of large junctional melanocytic nests that are more common in older individuals and/or associated with sun damage. However, the presence of large melanocytic nests alone does not lead to a diagnosis of malignancy, as they can also be found in melanocytic naevi. LNMs are challenging because they lack most classic histological features of malignancy and require thorough clinicopathological evaluation.
View Article and Find Full Text PDFPathology
September 2024
Department de Biopathologie, Centre Léon Bérard, Lyon, France; Université de Lyon, Université Claude Bernard Lyon 1, INSERM 1052, CNRS 5286, Centre Léon Bérard, Cancer Research Center of Lyon, Equipe Labellisée Ligue contre le Cancer, Lyon, France. Electronic address:
Recent data have redefined the genetic spectrum of pigmented epithelioid melanocytomas (PEMs). PEM is now defined by a secondary genetic event, a protein kinase cAMP-dependent type I regulatory subunit alpha (PRKAR1A) inactivation, that confers the specific cytomorphology of the entity, but this event can arise within a naevus with a genetic background of common, blue or Spitz type. PKC-fused melanocytic proliferations, although they can exhibit PEM-like morphological features, have now been regrouped within the blue group of tumours.
View Article and Find Full Text PDFLasers Surg Med
September 2024
Department of Dermatology, University of California, Irvine, California, USA.
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