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.

References

  • Wong CW, Fan YS, Chan TL, Chan AS, Ho LC, Ma TK, et al. BRAF and NRAS mutations are uncommon in melanomas arising in diverse internal organs. J Clin Pathol 2005;58:640-4.

  • Dominiak NR, Wick MR, Smith MT. Mucosal melanomas: site-specific information, comparisons with cutaneous tumors, and differential diagnosis. Semin Diagn Pathol 2016;33:191-7.

  • Wang L, Zong L, Nakazato H, Wang WY, Li CH, Shi YF, et al. Primary advanced esophago-gastric melanoma: a rare case. World J Gastroenterol 2016; 22:3296-3301.

  • Ascierto PA, Kirkwood JM, Grob JJ, Simeone E, Grimaldi AM, Maio M, et al. The role of BRAF V600 mutation in melanoma. J Transl Med 2012;10:85.

  • Wellbrock C, Hurlstone A. BRAF as therapeutic target in melanoma. Biochem Pharmacol 2010;80:561-7.

  • Lovly CM, Dahlman KB, Fohn LE, Su Z, Dias-Santagata D, Hicks DJ, et al. Routine multiplex mutational profiling of melanomas enables enrollment in gentotype-driven therapeutic trials. PLOS One, 2012;7:e35309.
  • Published: 2018-01-03

    Issue: Vol 5 No 3 (view)

    Section: Articles

    How to cite:
    Callaghan, G., Kelleher, F., Ridgway, P., Crowther, S., Alakkari, A., & Ryan, B. (2018). A Case of Primary Gastric Melanoma Exhibiting a Rare BRAF V600R Mutation. European Journal of Case Reports in Internal Medicine, 5(3). https://doi.org/https://doi.org/10.12890/2018_000749