A Twisting Diagnosis: A Case Report of Double Intussusception Uncovering an Unexpected Malignant Melanoma

We present the case of a 63-year-old female with a history of hypothyroidism, gastroesophageal reflux disease, hemorrhoids, hyperlipidemia, iron-deficiency anemia, and previously excised melanoma, who presented with 10/10 constant, dull right upper quadrant and epigastric pain, accompanied by nausea and vomiting. The patient had switched from prescribed iron supplements to over-the-counter ferrous sulfate tablets several weeks prior to admission due to gastrointestinal discomfort. Previous upper and lower endoscopies had shown benign polyps without bleeding, and she was scheduled for a capsule endoscopy by her gastroenterologist to evaluate her anemia and ongoing GI discomfort. On examination, she appeared in mild distress, with dry mucous membranes and abdominal tenderness with guarding. Laboratory tests revealed a hemoglobin level of 6.2 g/dL (previously 10.8 g/dL) and significantly elevated liver function tests (aspartate aminotransferase (AST) 677 U/L, alanine aminotransferase (ALT) 210 U/L). A CT scan of the abdomen and pelvis with IV contrast revealed two separate long-segment intussusceptions: one in the proximal jejunum and one in the distal ileum, both without discrete lead points on imaging. Given her history of melanoma, there was concern for metastatic disease. She underwent exploratory laparotomy with bowel resection and biopsy, which confirmed metastatic melanoma. This case highlights the rarity of dual-site intussusception in adults and underscores the importance of evaluating for malignancy as an underlying cause.