Retroperitoneal schwannoma sandwiched between abdominal aorta and inferior vena cava. A case report

Schwannomas are tumors that originate from the Schwann cells present in the nerve sheath of peripheral nerves. They are commonly seen in cephalocervical areas. Schwannomas in the abdominal cavity are rare. Here, we discuss a case of retroperitoneal schwannoma lying dorsal to pancreas with critical relations to surrounding vessels.

A 74 years old asymptomatic male was found with elevated amylase level on his routine blood examination. MR imaging revealed retroperitoneal mass of size 21*18*24 mm. EUS-FNA confirmed retroperitoneal schwannoma. The patient had co-morbid renal disease and was on hemodialysis. During the latest follow up, the tumor was 41*37*41 mm in size located dorsal to the confluence of right renal vein and inferior vena cava. The tumor was in contact with inferior vena cava, horizontal part of duodenum, right renal artery, right kidney, and adrenal gland. The patient underwent laparotomy and the tumor was extract with intact capsule. There were no post-operative complications.

Pre-operative diagnosis in retroperitoneal schwannomas is challenging because imaging features are usually non-specific, and biopsy is the only diagnostic technique. EUS-FNA, which has low diagnostic accuracy, is useful in pre-operative diagnosis of small tumors devoid of intra-tumoral degeneration.

Retroperitoneal schwannoma is a rare entity. Preoperative diagnosis and curative resection are technically difficult. Care should be given during preoperative investigations and surgical resection of the tumor. EUS-FNA can be a useful diagnostic tool.