Retroperitoneal schwannoma unusually presenting as severe constipation

Retroperitoneal schwannomas are rare tumours originating from Schwann cells of peripheral nerve sheaths. Their clinical presentation is often delayed as they grow to a large size in a non-restrictive space, such as the retroperitoneum, before any clear symptomatology is manifested. Furthermore, the symptoms may mimic different diseases and be aspecific. The preoperative diagnosis is often unclear as no pathognomonic radiological features are known. Fine needle biopsy is not diagnostic due to tumour cell pleomorphism. We report the case of a 51-year-old woman presenting with unusual symptoms such as severe constipation, bowel distension, excess flatus, postprandial fullness and abdominal pain due to left colon compression by a large retroperitoneal tumour. A complete resection of the mass combined with sparing of the surrounding tissues was carried out through a midline laparotomy. Microscopic evaluation and immunohistochemistry documented a benign retroperitoneal schwannoma. Postoperatively, complete resolution of abdominal symptoms and no major complications were observed. At 28 months' follow-up no local recurrence was found. To the best of our knowledge, this is a rare case of retroperitoneal schwannoma with definite abdominal symptoms and with sudden onset of severe constipation.