Gastrointestinal autonomic nerve sarcoma presenting as a giant intra-abdominal cyst.

Gastrointestinal autonomic nerve sarcomas are rare tumours. A 36-year-old man presented with abdominal pain, distension and constipation. Abdominal ultrasound and CT scanning demonstrated a giant cystic intra-abdominal mass. Laparotomy confirmed a large cystic mass arising from the ileum with multiple metastases. Immunohistochemical staining was positive for vimentin, neuronal-specific enolase and PGP9.5. This is the first reported case to present as a giant intra-abdominal cyst. Specialist histopathological and immunohistochemical analysis is essential to establish the diagnosis of this rare tumour.