Malignant Peripheral Nerve Sheath Tumour of Small Intestine Presenting as Ileo-Ileal Intussusception - A Rare Tumour with Unusual Complication.

Malignant Peripheral Nerve Sheath Tumours (MPNST) arises from a peripheral nerve or exhibit nerve sheath differentiation on histology. Proximal portions of the upper and lower extremities and the trunk are the most common sites of occurrence. Around 50% are associated with Neurofibromatosis Type 1 (NF1) with incidence of two to five per cent in patients with NF1. The estimated incidence in general population without NF1 is 0.0001% of which gastrointestinal MPNST are extremely rare. A 45-year-old lady without pathological antecedent for NF1 was admitted with pain in right lower abdomen and multiple episodes of vomiting for 3 months. Preoperatively intussusception was diagnosed in the small bowel with USG and CECT abdomen showing characteristic target sign. On laparotomy Ileo-ileal intussusception (proximal ileum telescoping into distal ileum) was found 2 feet proximal to ileo-caecal junction with surrounding inflammed mesentery and presence of intraluminal tumour as lead point. Resection of involved segment of ileum along with its mesentery was done followed by ileo-ileal anastomosis. Histopathology was suggestive of high grade MPNST. Postoperative course and follow up for last 10 month is uneventful. This case is unique in terms of a rare tumour presenting with unusual complication and only one case had been reported so far in western literature.