Pancreatic schwannoma: a case report and an updated 40-year review of the literature yielding 68 cases

Abstract

BackgroundPancreatic schwannoma is a rare tumor. Preoperative diagnosis of pancreatic schwannoma is challenging due to its tendency to mimic other lesions of the pancreas. We describe a case of pancreatic schwannoma and present a review of the cases currently reported in the English literature to identify characteristics of pancreatic schwannoma on imaging.Case presentationA 53-year-old male presented with a history of intermittent periumbilical abdominal pain and lower back pain for 1 week. Based on ultrasound (US) and computed tomography (CT) findings, we made a preoperative diagnosis of solid pseudopapillary tumor and performed a standard pancreaticoduodenectomy. Pathological examination showed that the tumor was composed of spindle cells with a palisading arrangement, and immunohistochemistry revealed strong positive staining for S-100 protein, which was consistent with a diagnosis of pancreatic schwannoma. At the 8-month follow-up visit, the patient was doing well without recurrent disease, and his abdominal pain had resolved.ConclusionsAlthough pancreatic schwannoma is rare, it should be included in the list of differential diagnoses of pancreatic masses, both solid and cystic. A tumor size larger than 6.90 cm, vascular encasement, or visceral invasion should elicit suspicion of malignant transformation.

Cystic pancreatic schwannoma diagnosed by endoscopic ultrasound‐guided fine needle aspiration

“…Half of patients presented with abdominal pain, but 34% were asymptomatic. The lesions were most commonly located in either the head or the body of the pancreas, and the majority (65%) had a cystic component . Similar findings were reported by Moriya et alin an earlier study …”

“…Schwannomas are benign nerve sheath tumors commonly arising in the head and neck and extremities, and occasionally occurring in deep‐seated locations including the posterior mediastinum and retroperitoneum . Their origin in the pancreas is rare, with fewer than 70 cases reported in the literature . In a recent review, Ma and colleagues summarized the features of 68 published cases of pancreatic schwannoma.…”

“…Their origin in the pancreas is rare, with fewer than 70 cases reported in the literature . In a recent review, Ma and colleagues summarized the features of 68 published cases of pancreatic schwannoma. Half of patients presented with abdominal pain, but 34% were asymptomatic.…”

“…However, there are very few case reports in the cytology literature of pancreatic schwannoma diagnosed by FNA . In the cohort of cases reviewed by Ma et al 16 patients underwent EUS‐FNA, but only half of cases were correctly interpreted as pancreatic schwannoma preoperatively . However, if adequate diagnostic material is obtained, the distinction between schwannoma and other pancreatic cystic lesions is fairly straightforward.…”

Metastatic leiomyosarcoma to the pancreas diagnosed on endoscopic ultrasound‐guided fine needle aspiration – A report of two cases with review of spindle cell lesions of pancreas

“…Mesenchymal spindle cell neoplasms are one of the most challenging aspects of cytology with considerable overlap in morphology and ICC. Gastrointestinal stromal tumour (GIST), leiomyoma, ganglioneuroma,schwannoma, desmoids fibromatosis, solitary fibrous tumour (SFT), inflammatory myofibroblastic tumour, low‐grade myofibroblastic sarcoma and neurofibroma are all reported in the pancreas. These lesions show tightly cohesive cellular fragments of spindle cells variably arranged in fascicular pattern associated with metachromatic matrix material.…”