A Rare Case of Gastrointestinal Bleeding Due to Primary Intestinal Melanoma

Abstract

Introduction: We present a rare case of primary small intestine melanoma. Case Report: A 69-year-old male with a history of colon polyps presents with dark stool and fatigue. His hemoglobin dropped from 16 to 11. EGD showed possible Barrett’s esophagus. Biopsy was negative for metaplasia. He had a nodule of the second portion of the duodenum. Biopsy showed normal mucosa. Colonoscopy showed hemorrhoids, diverticulosis, and normal terminal ileum. A 3-mm tubular adenoma was removed from the colon. Small bowel (SB) capsule showed a moderate-sized semi-circumferential mass in the jejunum with areas of ulceration and bleeding. A CT abdomen showed small bowel mass in the distal jejunum. Adjacent enlarged lymph nodes (LN) are suspicious for metastatic disease. The patient underwent exploratory laparotomy and partial SB resection. Pathology reveals malignant melanoma. LN was negative for metastasis. Skin evaluation by dermatology did not find any lesions that were concerning for dysplastic nevi. Ophthalmology evaluation was normal. MRI of the brain revealed no metastatic process. PET-CT revealed intense hypermetabolism in the small bowel at the area of the surgical site without any evidence of metastatic disease. He followed up with oncology and his repeat PET scan and capsule endoscopy remained negative for recurrence of cancer. Discussion: Intestinal melanomas can be primary tumors or metastases of cutaneous, ocular, or anal melanomas. Primary intestinal melanoma is extremely rare. Most cases of SB melanoma are metastases from cutaneous melanoma. Metastases to the gastrointestinal tract are found at autopsy in 60% of patients who die with malignant melanoma. The clinical picture of SB melanoma is similar to the clinical presentation of other tumors involving the SB. Thus, patients with a history of cutaneous melanoma who have intermittent abdominal pain or anemia should be investigated to rule out intestinal metastases. Diagnosis can be made by ultrasound, barium studies, endoscopy, CT, or PET. A combination of imaging techniques is recommended to improve the sensitivity and specificity of radiological imaging. No standard therapy exists for the treatment of intestinal melanoma, although surgical removal is the treatment of choice in all patients with resectable melanoma. Accurate preoperative diagnosis and assessment of the extent of intestinal metastases is essential when selecting patients for surgery. Systemic chemotherapy regimens show no benefit to overall survival. The prognosis is poor, with an overall median survival of 6-9 months and a 5-year survival rate of less than 10%. Conclusion: Primary intestinal melanoma is very rare condition with poor prognosis. Early detection and surgical resection are vital to disease survival.