Rare ileocaecal intussusception from small bowel adenocarcinoma

Intussusception in adults is uncommon, representing only 1% of bowel obstruction cases and often indicates an underlying pathological mass, frequently requiring surgical resection. This report presents a rare histological subtype of adenocarcinoma in an adult, complicated by extensive ileocolic intussusception. A female in her mid-fifties presented with acute abdominal pain, nausea, vomiting, and rectal bleeding. Imaging revealed a 20 cm ileocolic intussusception caused by a calcified mass in the ileum. A laparotomy revealed a grossly oedematous ileum and a palpable mass as the lead point within it. A small bowel wedge resection was performed. Histopathology showed a poorly differentiated adenocarcinoma with focal neuroendocrine differentiation (NED). The patient’s recovery was prolonged, and subsequent CT studies have not demonstrated recurrence so far. Small bowel cancer, although rare, is on the rise. Adenocarcinomas are the most common histological subtype, and neuroendocrine differentiation in such tumours is extremely rare. This represents a rare instance of ileal adenocarcinoma with neuroendocrine differentiation in a patient with unaltered anatomy. The presence of neuroendocrine differentiation may confer a poorer prognosis, as seen in other gastrointestinal tumours, however the long-term behaviour and management of this rare subtype remains unclear. Further research is needed to understand the prognostic implications and to develop a standardised treatment regimen for this rare pathology.