1997 Isolated Duodenal Melanoma: A Rare Cause of Gastrointestinal Bleed

Abstract

INTRODUCTION: Melanomas are known to be the worst dermatologist nightmare, being notorious due its widespread metastasis and recurrence. They can present with any symptom based on the involvement of the organ but it is exceedingly rare for melanoma to present as an isolated duodenal mass in the absence of skin lesions. CASE DESCRIPTION/METHODS: A 79 years old white male, with history of coronary artery disease was admitted with exertional shortness of breath and atypical chest pain. His symptoms started over a course of few days and was associated generalised weakness and fatigue. He never had an upper gastrointestinal endoscopy done and colonoscopy two years was normal. His home medications included aspirin and beta blocker. On examination, he was tachycardia with a heart rate of 100 bpm and blood pressure was 90/60. He was afebrile but tachypneic with a respiratory rate of 22/min. Systemic examination was unremarkable except pallor and rapid thready pulse. The laboratory investigation showed a hemoglobin of 8 g/dL, MCV of 80, platelet count of 189,000/mL and white blood cell counts of 8,000/mL. Esophagogastric duodenoscopy (EGD) was performed on the second hospital day which revealed a duodenal nodule. Biopsy was obtained from the lesion, no signs of active bleeding was observed. The biopsy was positive for metastatic melanoma. Immunohistochemical stains on parts A and B revealed the tumor cells to be positive for S100 and SOX10, and negative for synaptophysin, panCK, c-kit, and Dog 1.(Figure 1) Patient’s whole body was scanned but it did not show any other melanoma lesion and there was no primary melanoma on the skin either. Helicobacter pylori stains, performed on the gastric and duodenal biopsies, were negative. He was managed conservatively with pantoprazole 40 mg and regular follow up as patient refused surgery. DISCUSSION: It is exceedingly rare to have isolated duodenal melanoma in the absence of skin lesions and physicians should keep a high index of suspicion for these rare cases. Local resection of the mucosal melanoma (including in stomach and small intestine), with negative margins, should be considered first line treatment in patients without distant metastasis while conservative management with surveillance in patients can be considered in selected cases.