title: Utilization of polarized microscopy to differentiate deep penetrating nevus from equine type melanomas.
abstract: Equine type melanoma can mimic deep penetrating nevus (DPN), making histologic diagnosis challenging. We sought to investigate if the pattern of collagen polarization could be helpful in this setting. A total of 52 specimens were reviewed with polarized microscopy to determine whether refractile collagen was present within melanocytic nests vs. surrounding but not within the nests. Seven of eight (87.5%) equine type melanomas demonstrated refractile collagen within melanocytic nests in part or all of the lesion. In contrast, DPN showed no refractile collagen within the melanocytic nests. Instead, 12 (100%) DPNs and 14 of 16 (87.5%) common combined nevi (DPN plus banal nevus) demonstrated refractile collagen only surrounding melanocytic nests. The entrapment of refractile collagen, as seen with polarized microscopy, within melanocytic nests can support a diagnosis of equine type melanoma.
authors.affiliation: Ackerman Academy of Dermatopathology, New York, NY, USA.
authors.forename: Nathan
authors.initials: N
authors.lastname: Cleaver
authors.affiliation: Robert Wood Johnson Medical School, New York, NY, USA.
authors.forename: Kruti
authors.initials: K
authors.lastname: Parikh
authors.affiliation: Ackerman Academy of Dermatopathology, New York, NY, USA.
authors.forename: Viktoryia
authors.initials: V
authors.lastname: Kazlouskaya
authors.affiliation: Medical University of South Carolina, SC, USA.
authors.forename: Dirk
authors.initials: D
authors.lastname: Elston
mesh_terms: D003094:Collagen / Q000378:metabolism*; D005260:Female; D006801:Humans; D008297:Male; D008545:Melanoma / Q000378:metabolism / Q000473:pathology; D008859:Microscopy, Polarization; D009363:Neoplasm Proteins / Q000378:metabolism*; D009506:Nevus / Q000378:metabolism / Q000473:pathology; D012878:Skin Neoplasms
chemical_list: D009363:Neoplasm Proteins; D003094:Collagen
keywords: dermatopathology; melanocytic lesions; melanoma