Small bowel intussusception and GI bleed secondary to metastatic melanoma: A case report and literature review

Malignant melanoma (MM) is the most common malignancy to metastasize to the gastrointestinal (GI) tract, with the small bowel being the most frequently affected site. GI metastases often remain asymptomatic but can present with abdominal pain, weight loss, obstruction, or bleeding. Diagnosis relies on imaging and endoscopic techniques, with PET-CT being the most sensitive. We report a case of a 58-year-old woman with a history of cutaneous melanoma in situ excised 26 years ago, now presenting with a 3-month history of abdominal symptoms, melena, and weight loss. Work-up revealed anemia and positive occult blood, with negative gastroscopy and colonoscopy. CT confirmed jejuno-jejunal intussusception, and enteroscopy identified multiple pigmented lesions. Biopsy confirmed malignant melanoma, and PET-CT showed multifocal involvement. The patient underwent laparotomy with bowel resection and jejunostomy, followed by immunotherapy, leading to complete tumor resolution and no recurrence on follow-up PET-CT. This case report highlights a very rare finding of small bowel metastasis after cutaneous melanoma-in situ excision leading to jejuno-jejunal intussusception, with disease free interval of over 25 years.