A Case of Primary Gastric Melanoma Exhibiting a Rare BRAF V600R Mutation
  • Grainne Callaghan
    Department of Gastroenterology, Tallaght Hospital, Dublin, Ireland
  • Fergal Kelleher
    epartment of Medical Oncology, Tallaght Hospital, Dublin, Ireland
  • Paul Ridgway
    Department of Surgery, Tallaght Hospital, Dublin, Ireland and Department of Surgery, Trinity College Dublin, Ireland
  • Stephen Crowther
    Department of Cellular Pathology, Tallaght Hospital, Dublin, Ireland
  • Alaa Alakkari
    Department of Gastroenterology, Tallaght Hospital, Dublin, Ireland
  • Barbara Ryan
    Department of Gastroenterology, Tallaght Hospital, Dublin, Ireland and Department of Clinical Medicine, Trinity College Dublin, Ireland

Keywords

Gastric melanoma, malignant melanoma, BRAF

Abstract

Introduction: Malignant melanoma of the gastrointestinal tract is usually a metastasis from a cutaneous source. Primary gastric melanoma is an extremely rare clinical entity, with few reported cases worldwide. It is often advanced at time of diagnosis and is associated with a dismal outcome.

Background: A 76 year old gentleman presenteded with a one month history of fatigue and exertional dyspnoea. Laboratory investigations indicated an anaemia, with a haemoglobin level of 11.0g/dl. Subsequent gastroscopy visualised a large, atypical, crater-like ulcerated lesion distal to the cardia in the proximal stomach.
Provisional histology was suggestive of a poorly differentiated adenocarcinoma but subsequent cyto-morphology and immunophenotyping were consistent with melanoma, with positive S100 protein, HMB45 and Melan A. Further molecular genetic testing revealed a V600R mutation in the BRAF gene, which is the first primary gastric melanoma with this mutation to be reported in the literature. Given the rarity of the findings, an extensive secondary work-up was undertaken, which concluded the diagnosis primary gastric melanoma. Discussion: Primary gastric melanoma is a rare disease that can present similarly to other upper gastrointesinal lesions, with weight loss, abdominal pain, malena, and anaemia. Given its rarity, the pathogenesis is poorly understood. Lesions are often endoscopically atypical. Important points to note would include the absence of a primary lesion, as supported by a full skin examination and PET-CT findings, which can help to delineate the limitation to the stomach, thus helping to inform subsequent management.

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    Published: 2018-01-03
    Issue: Vol. 5 No. 3 (view)

    How to cite:
    1.
    Callaghan G, Kelleher F, Ridgway P, Crowther S, Alakkari A, Ryan B. A Case of Primary Gastric Melanoma Exhibiting a Rare BRAF V600R Mutation. EJCRIM 2018;5 doi:10.12890/2018_000749.

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