Metastatic Melanoma Causing Intussusception in the Small Bowel: A Case Report.

Intussusception is a condition in which a part of the intestine telescopes into an adjacent segment of the bowel. This can obstruct the passage of food and fluids and may compromise the blood supply, leading to bowel obstruction, ischemia, infection, or perforation. Common symptoms include constipation, bloating, nausea, vomiting, and abdominal pain. Diagnosis is typically confirmed with computed tomography (CT) or ultrasonography, and definitive treatment involves bowel resection or reduction. We present the case of a 54-year-old man with a history of metastatic malignant melanoma, previously in complete remission following immunotherapy, who developed small bowel obstruction secondary to intussusception. He initially presented with a three-week history of loose stools, followed by a week of bilious vomiting, abdominal pain, and absence of bowel movements. A CT scan of the abdomen and pelvis revealed two sites of intussusception at the distal jejunum and distal ileum. The patient underwent exploratory laparotomy with resection of both affected small bowel segments and primary anastomoses. Postoperatively, he made a full recovery without complications. Histopathology confirmed metastatic malignant melanoma infiltrating both bowel segments, with clear resection margins and no lymphovascular invasion. Melanoma most commonly metastasizes to the gastrointestinal tract via hematogenous or lymphatic spread, with the small bowel being the most frequent site of involvement. This case illustrates a rare yet clinically significant instance of metastatic melanoma presenting as dual-site small bowel intussusception occurring more than a year after apparent remission with immunotherapy. It emphasizes that gastrointestinal metastases from melanoma can develop insidiously, even in the absence of cutaneous recurrence, and may present solely with nonspecific obstructive symptoms. CT remains the cornerstone of diagnosis, while surgical resection serves as both diagnostic and curative. Importantly, this case underscores the need for ongoing vigilance and long-term follow-up in patients with a history of metastatic melanoma, as timely recognition and surgical management can significantly improve outcomes and quality of life.