Pancreatic schwannoma: Case report and an updated 30-year review of the literature yielding 47 cases

Abstract

Pancreatic schwannomas are rare neoplasms. Authors briefly describe a 64-year-old female patient with cystic pancreatic schwannoma mimicking other cystic tumors and review the literature. Databases for PubMed were searched for English-language articles from 1980 to 2010 using a list of keywords, as well as references from review articles. Only 41 articles, including 47 cases, have been reported in the English literature. The mean age was 55.7 years (range 20-87 years), with 45% of patients being male. Mean tumor size was 6.2 cm (range 1-20 cm). Tumor location was the head (40%), head and body (6%), body (21%), body and tail (15%), tail (4%), and uncinate process (13%). Thirty-four percent of patients exhibited solid tumors and 60% of patients exhibited cystic tumors. Treatment included pancreaticoduodenectomy (32%), distal pancreatectomy (21%), enucleation (15%), unresectable (4%), refused operation (2%) and the detail of resection was not specified in 26% of patients. No patients died of disease with a mean follow-up of 15.7 mo (range 3-65 mo), although 5 (11%) patients had a malignancy. The tumor size was significantly related to malignant tumor (13.8 ± 6.2 cm for malignancy vs 5.5 ± 4.4 cm for benign, P = 0.001) and cystic formation (7.9 ± 5.9 cm for cystic tumor vs 3.9 ± 2.4 cm for solid tumor, P = 0.005). The preoperative diagnosis of pancreatic schwannoma remains difficult. Cystic pancreatic schwannomas should be considered in the differential diagnosis of cystic neoplasms and pseudocysts. In our case, intraoperative frozen section confirmed the diagnosis of a schwannoma. Simple enucleation may be adequate, if this is possible.

Keywords: Cystic; Enucleation; Imaging; Neurinoma; Pancreas; Pancreatic schwannoma; Prognosis; Resection; Schwannoma.

Figure 1

Contrast-enhanced computed tomography scan obtained in the arterial phase showing a multilocular cystic mass in the uncinate process of the pancreas. No pancreatic ductal dilatation or invasion into adjacent arteries or portal vein are identified.

Figure 2

Intraoperative ultrasound showing the well-encapsulated pancreatic mass that is composed of solid and cystic components.

Figure 3

Microscopic examination demonstrating spindle cells without nuclear atypism (HE x 100). Immunohistochemical staining for S-100 protein was positive. HE: Hematoxylin and eosin.

Figure 4

Analysis for relation between tumor size and malignant potential and tumor nature (solid or cystic) in all 47 cases of pancreatic schwannoma. A: Relationship between tumor size and malignancy. Larger tumor size is related to malignant tumor (13.8 ± 6.2 cm for malignancy vs 5.5 ± 4.4 cm for benign, P = 0.001); B: Relationship between tumor size and nature of tumor. Larger tumor size is related to cystic degeneration (13.8 ± 6.2 cm for cystic tumor vs 5.5 ± 4.4 cm for solid tumor, P = 0.005).