Here, we report a very rare case of melanocytic nevus of the colon. A 54-year-old woman with an unremarkable medical history visited our hospital for screening colonoscopy. Colonoscopy revealed a pigmented flat lesion in the ascending colon. Histological evaluation of a biopsy specimen revealed proliferation of pigmented cells in the lamina muscularis propria. On immunohistochemical analysis, pigmented cells were positive for S-100 protein and Melan-A expression, and a diagnosis of colonic melanocytic nevus was made. Although the pathogenesis underlying colonic melanocytic nevi remains unclear, we speculate that colonic melanocytic nevi develop via abnormal migration or differentiation of neural crest cells during embryogenesis.
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http://dx.doi.org/10.1159/000501196 | DOI Listing |
JAAD Case Rep
February 2025
Dermatology Department, New York Medical College, Valhalla, New York.
Plast Reconstr Surg Glob Open
January 2025
From the Division of Plastic and Reconstructive Surgery, Faculty of Medicine, American University of Beirut Medical Center, Beirut, Lebanon.
Giant congenital melanocytic nevi are large pigmented premalignant lesions present at birth that have an associated risk of malignant transformation. Full-thickness excision of these lesions would be required to eliminate this risk. However, giant nevi can leave behind large defects that can be challenging to reconstruct.
View Article and Find Full Text PDFAustralas J Dermatol
January 2025
QCIF Bioinformatics, Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia.
Background/objectives: Congenital melanocytic naevi (CMN) are a risk factor for melanoma. Melanoma risk is dependent on the congenital phenotype. Our primary aims were to assess the clinical characteristics of CMN that indicate a high risk of neurocutaneous melanosis (NCM) and melanoma in an Australian paediatric population group; to identify patient characteristics and clinical features of CMN that trigger further investigations; and to determine the rate of malignancy and other complications for CMN.
View Article and Find Full Text PDFBMJ Case Rep
January 2025
Dermatology, Zuckerberg San Francisco General Hospital, University of California San Francisco, San Francisco, California, USA.
A woman in her 70s with well-controlled HIV on antiretroviral therapy presented with a several-month history of an asymptomatic perianal lesion. Skin examination showed a 0.5-1 cm red-pink, shiny, exophytic papule with visible telangiectasias near the anal verge.
View Article and Find Full Text PDFJ Dermatol
January 2025
Department of Dermato-Oncology/Dermatology, NHO Kagoshima Medical Center, Kagoshima, Japan.
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