Two Adult Cases of Intussusception: Both Caused By Metastatic Melanoma

Abstract

Case 1: A 72 y/o male with a history of melanoma presented with anemia and melena. The initial EGD and colonoscopy were unremarkable, however capsule endoscopy showed multiple ulcerations in the proximal small bowel and a bleeding mass in the distal small bowel. These findings prompted a CT enterography, which demonstrated multiple small bowel enhancing masses with associated intussusceptions. The patient then underwent push enteroscopy and repeat colonoscopy with terminal ileum intubation. The push enteroscopy revealed small bowel erythematous polyps with central ulcerations and upon intubation of the ileum on repeat colonoscopy, two partial obstructing masses were found. Biopsies of all of the lesions confirmed metastatic melanoma. Case 2: A 20 y/o female presented with intermittent left lower quadrant pain and hematochezia. The patient was diagnosed 3 years prior with superficial spreading melanoma with subsequent wide local excision and node sampling. She had clear margins and negative lymph nodes at that time. Two years later, she was found to have metastatic lesions in her subcutaneous tissues, muscles, spleen, and lungs. The patient was treated with 4 cycles of ipilimumab. CT scan following treatment and during follow up showed overall improvement in her metastatic burden. There was never any suspicion by clinical symptoms or imaging of any GI tract involvement. At the time of her presentation for new symptoms of abdominal pain and hematochezia, CT revealed a colocolic intussusception involving the sigmoid colon. The patient underwent a colonoscopy and a completely obstructing pigmented mass was found 40 cm from the anal verge. Several biopsies were obtained which confirmed the lesion to be metastatic melanoma. The patient underwent laparoscopic resection of the sigmoid colon. Discussion: Bowel intussusception is uncommon in the adult population and colocolic intussusception is particularly rare. In adults, intussusception typically involves a distinct lead point that is malignant in greater than 50% of cases. The small bowel (jejunum, ileum) is the most common gastrointestinal site of melanoma metastasis, with spread to the colon not as frequently seen. Typical symptoms of metastatic melanoma to the gastrointestinal tract include GI bleeding, anemia, abdominal pain, and as with these two cases, occasionally intussusception. Conclusion: In patients with a history of melanoma presenting with anemia, abdominal pain or gastrointestinal bleeding, metastatic lesions within the bowel should be suspected. The presence of an intussusception in adults, particularly in the colon, should be presumed malignant until proven otherwise.