A case of pancreatic schwannoma - The features in imaging studies compared with its pathological findings: Report of a case

Clinical benefits of central pancreatectomy for a patient with pancreatic schwannoma and diabetes

Schwannomas are tumors that originate from the glial cells of the nervous system and can occur on myelinated nerve fibers throughout the body, especially in the craniofacial region. However, pancreatic schwannomas are extremely rare. We report a case of a pancreatic schwannoma that was difficult to differentiate from other pancreatic tumors preoperatively. A 44-year-old female patient was found to have a pancreatic mass on Computed Tomography imaging and the preoperative diagnosis was a pancreatic solid pseudopapillary neoplasm. Meanwhile, the patient had type 2 diabetes and the blood glucose was controlled at 8-15mmol/L by taking oral antidiabetic drugs. During exploratory laparotomy, an 8 cm × 7 cm × 4 cm mass was discovered in the middle part of the pancreas. Considering the preoperative diabetes, the patient underwent a central pancreatectomy (CP) and Roux-en-Y pancreaticojejunostomy. Postoperative histopathological examination confirmed the diagnosis of a pancreatic epitheloid schwannoma. After surgery, the patient developed Grade B pancreatic fistula, which disappeared after treatment. At the same time, the patient's blood glucose remained basically stable by insulin therapy, which was adjusted to oral antidiabetic medications in about 40 days after surgery. At a 32-month follow-up after discharge, no tumor recurrence was observed, and the patient's blood glucose was controlled below 11.1mmol/L with only oral antidiabetic drugs. The radiological diagnosis of pancreatic schwannomas lacks specific features, and diagnosis primarily relies on histopathological examination and immunohistochemical testing. Although pancreatic schwannomas are extremely rare, they must be differentiated from other solid or cystic pancreatic lesions. For patients with pancreatic schwannoma and diabetes, CP may represent a favorable surgical option.

Successful treatment of pancreatic schwannoma by enucleation: A case report

RATIONALE

Pancreatic schwannomas are extremely rare and are difficult to diagnose preoperatively. Over the past 50 years, only 96 cases of pancreatic schwannoma have been reported in English literature. Herein, we report a case of pancreatic schwannoma treated with enucleation.

PATIENT CONCERNS

A 66-year-old woman visited a local hospital due to ventosities. Ultrasonography and computed tomography revealed a pancreatic mass. She visited our hospital for further diagnosis and treatment.

DIAGNOSIS AND INTERVENTIONS

Magnetic resonance imaging revealed a tumor in the pancreatic body, and a solid pseudopapillary tumor was considered preoperatively. During the surgery, a pancreatic mass was found growing in the pancreatic body and tail. A successful tumor enucleation was performed. The mass was 7 × 6 × 3 cm in size with a thin capsule. Pathological examination revealed that the tumor was mainly composed of spindle-shaped cells with a palisading arrangement and no atypia. Both hypercellular and hypocellular areas were visible. Immunohistochemical staining showed that protein S-100 was strongly positive. The tumor was diagnosed as a benign schwannoma originating from the pancreatic body and tail.

OUTCOMES

Postoperatively, the patient showed good recovery. During the 24-month follow-up period, the patient remained well and free of complications.

LESSONS

Pancreatic schwannomas are extremely rare and difficult to diagnose using imaging examinations. Enucleation is a safe and efficacious treatment for exophytic pancreatic schwannomas.

Peripancreatic schwannoma: A case report

Introduction

Schwannomas are a benign tumor of peripheral nerve sheath origin. Although most commonly arising in the extremities, head, and neck there have been rare cases of schwannomas presenting within or adjacent to the pancreas reported in the literature.

Presentation of case

We present an asymptomatic and otherwise healthy 57-year-old male with an incidental peripancreatic mass measuring 3.5 × 3.7 cm found on abdominal computed tomography (CT). The patient underwent complete enucleation of the mass at our hospital. Pathological analysis of the excised specimen showed spindle shaped cells. Immunohistochemical staining was positive for S100 protein expression, confirming the definitive diagnosis of peripancreatic schwannoma. The patient's postoperative course was uneventful.

Discussion

Schwannoma is a commonly benign, encapsulated, and slowly growing tumor arising from myelin producing cells of peripheral nerves. A schwannoma presenting within or adjacent to solid abdominal viscera, such as the pancreas, may be challenging to diagnose preoperatively as it may mimic other lesions. Radiological appearance of schwannoma may be nonspecific and definitive diagnosis is reliant upon pathological analysis. The use of endoscopic ultrasound (EUS) with fine needle aspiration (FNA) may assist the clinician in preoperative diagnosis, however these interventions are not widely available. Accurate preoperative diagnosis of a peripancreatic schwannoma is of high importance as it may preclude unnecessary pancreatectomy or radical resection.

Conclusion

Although rare, schwannoma should be part of the differential diagnosis of a cystic or solid appearing mass within or surrounding the pancreas. Total resection carries an excellent prognosis with little to no documented recurrence.

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Peripancreatic schwannoma is rare, but should be considered in the differential diagnosis of an incidentally found mass

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Histopathological features of schwannoma

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Radiological features of schwannoma

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Enucleation of peripancreatic schwannoma carries excellent prognosis

MR imaging features of pancreatic schwannoma: a Chinese case series and a systematic review of 25 cases

BACKGROUND

There is a paucity of existing literature centering on the magnetic resonance (MR) imaging features of pancreatic schwannomas, due to the neoplasm's nonspecific presentation and its rarity. We aimed to identify the characteristic imaging features of pancreatic schwannoma.

METHODS

This retrospective search was conducted for histologically confirmed pancreatic schwannoma in multi-institutional database of pathology. Abdominal magnetic resonance imaging (MRI) was performed before histologic examination and their MR imaging studies were independently reviewed. The search yielded six adults (mean age, 46 years) with a definitive histologic postoperative diagnosis of single pancreatic schwannoma each. Additionally, a comprehensive English and Chinese literature review for pancreatic schwannoma and reported MR-imaging findings since 1961 was also conducted. MR imaging features of those cases in the literature were analyzed, summarized and compared with our case series.

RESULTS

This rare entity appeared to be a well-circumscribed, exophytic, oval or round pancreatic mass with a mean greatest diameter of 3.7 cm. Five schwannomas were located in the pancreatic head-neck and one in the pancreatic tail. On MRI, all cases appeared hypointense on T1-weighted images, inhomogeneous hyperintense on T2-weighted images, and hyperintense on diffusion-weighted images. The mean apparent diffusion coefficient (ADC) values of pancreatic schwannoma were 1.11 ± 0.29 × 10- 3 mm2/s and significantly lower than the surrounding pancreas. The lesion-to-pancreas signal intensity ratio (SIR) at unenhanced T1-weighted images was 0.53 ± 0.07. On dynamic contrast-enhanced MRI, most of the lesions (67%, 4/6) showed homogeneously iso- or hypointense on arterial and portal venous phases, and hyperenhancement on delayed phase compared with the surrounding pancreas. In our analysis of the time intensity curves, all cases exhibited a gradual enhancement pattern.

CONCLUSIONS

A well-circumscribed mass displaying inhomogeneous hyperintensity on T2, marked hypointensity on T1, hyperintensity on DWI, and with early slight enhancement at arterial phase and progressive enhancement at portal venous and delayed phase, may suggest the diagnosis of pancreatic schwannoma.

Hepatic Schwannoma on 18F-FDG PET/CT

Schwannoma is a slow-growing benign tumor, which originates from Schwann cells and is usually asymptomatic. The most common sites of schwannomas are the head, neck, and extremities. However, a schwannoma located in the liver is extremely rare. Here, we report a 53-year-old woman with a hepatic lesion accidentally found by ultrasound. It was highly suggestive of hepatic cholangiocarcinoma by MRI. F-FDG PET/CT could not exclude hepatic malignant tumor due to its high metabolism. Finally, it was confirmed as hepatic schwannoma by postoperative pathology.

Pancreatic Nerve Sheath Tumors: a Single Institutional Series and Systematic Review of the Literature

INTRODUCTION

Improvement in imaging has resulted in frequent diagnosis of benign and premalignant pancreatic tumors. Pancreatic nerve sheath (PNS) tumors are one of the rarest pancreatic tumors. Literature on PNS is limited and their biology is poorly understood. Here, we report the largest series of PNS tumors to date and review the literature to evaluate the current data available on PNS tumors.

METHODS

An institutional database was used to identify patients who underwent resection for PNS tumors. Clinicopathological characteristics and outcomes of these patients were reported. Furthermore, a review of literature was performed.

RESULTS

From January 1994 through December 2016, seven patients underwent resection for PNS tumors. The median age was 57.7 years (IQR, 44.9-61.9) and the sex was approximately equally distributed (male = 4; 57.1%). Three (42.9%) patients were diagnosed incidentally and six (85.7%) were misdiagnosed as having other pancreatic tumors. The median tumor size was 2.1 (IQR 1.8-3.0) cm and six (85.7%) had no nodal disease. At a median follow-up of 15.5 (IQR 13.7-49.3) months, six patients were alive without evidence of disease and one patient was lost to follow-up. The literature review identified 49 studies reporting 54 patients with PNS tumors. Forty-six were misdiagnosed as having other pancreatic tumors. The median tumor size was 3.6 (range 1-20) cm, nodal disease was present in six patients (22.2%), and no patient had distant metastatic disease. At the time of last follow-up, all patients were free of disease.

CONCLUSION

This is the largest single institution series on PNS tumors reported to date. These tumors are rare and are often misdiagnosed, given their radiological characteristics. PNS tumors have a benign course of disease and surgical resection results in favorable long-term outcomes.

Pancreatic schwannoma, an extremely rare and challenging entity: Report of two cases and review of literature

Pancreatic schwannoma is a rare benign tumor, for which the preoperative and intraoperative definitive diagnosis is quite challenging. We present the clinical, radiological and pathologic features of two primary pancreatic schwannomas identified in our pathology database over a period of 30 years at our tertiary care hospital. To better understand the clinico-pathological and radiological features of this entity, we provide a comprehensive review of 73 cases described in the English literature, along with our two cases. This review will especially focus on preoperative and intraoperative diagnosis to assess their accuracy for pancreatic schwannoma. The three most common preoperative diagnoses based on imaging for pancreatic schwannomas were cystic neoplasm (56%), pancreatic neuroendocrine tumor (29%) and mucinous cystic neoplasm (26%). Imaging could not definitely diagnose pancreatic schwannoma in any of the reported cases. To obtain a definite diagnosis before surgery, 25 cases underwent imaging-guided fine-needle aspiration (FNA)/biopsy, of which 60% were correctly reported as benign with definite diagnosis of pancreatic schwannoma in 48%. A higher diagnostic accuracy was observed in biopsies (71%) than FNA (37%). In addition, an intraoperative frozen section was carried out in 15 cases, and 47% were correctly diagnosed. Despite relatively low accuracy, preoperative histological assessment can be helpful in surgical managment. A core tissue specimen is recommended to improve the diagnostic accuracy in this setting.

Pancreatic schwannoma mimicking pancreatic cystadenoma: A case report and literature review of the imaging features

INTRODUCTION

Schwannomas, also known as neurilemmoma, are benign neoplasms that originating from Schwann cells in peripheral nerve sheaths. The head, neck, and extremities are the most common sites; however, pancreatic schwannomas are rare neoplasms. Accurate preoperative diagnosis of these tumors is very tough because of pancreatic schwannomas usually mimicking other cystic tumors. Here we present a case of pancreatic schwannoma misdiagnosed as pancreatic cystadenoma.

PATIENT CONCERNS

We presented a rare case of a 55-year-old female admitted to our hospital for abdominal distension. The physical examination and results of laboratory testing reveal no abnormalities.

DIAGNOSIS

A computed tomography (CT) scan detected a hypodense 2.4 cm × 2.6 cm mass with a clear margin at the neck of the pancreas. Pancreatic cystadenoma was strongly suspected.

INTERVENTIONS

The patient underwent robotic distal pancreatectomy with splenectomy. The gross specimen showed a pale and solid mass with a capsule.

OUTCOMES

Histological examination of the surgical specimen demonstrated a pancreatic schwannoma. Immunohistochemistry results were as follows: S-100 (+), CD117 (-), SMA (-), and Desmin (-). She was discharged on postoperative day 6 and no recurrence of the tumor happened during the 12-month follow-up.

CONCLUSION

Precise preoperative diagnosis of pancreatic schwannomas is very difficult despite the application of multiple imaging modalities. Surgery is the most effective treatment for this rare disease and the final diagnosis usually relies on pathology. Following complete tumor removal, patients with pancreatic schwannomas generally have a good prognosis.

Successful treatment of a pancreatic schwannoma by spleen-preserving distal pancreatectomy

Schwannomas are neurogenic tumors that arise from the neural sheaths of peripheral nerves. These tumors can be located in any area of the human body; the most common locations are the head, neck, trunk and extremities. Pancreatic schwannomas are very rare. Over the past 40 years, only 67 cases of pancreatic schwannomas have been reported in the English literature. Here we present a case of pancreatic schwannoma in a 62-year-old male. The tumor was revealed by ultrasound and computed tomography in the neck and body of the pancreas. An accurate diagnosis was difficult to obtain preoperatively. The patient consented to the performance of a laparotomy, and the mass was found in the neck and body of the pancreas and successfully treated using a spleen-preserving distal pancreatectomy with splenic artery and vein preservation. The procedure has only been reported in one other case of pancreatic schwannoma; here we present the second reported case. Macroscopically, the tumor was well circumscribed, gray-white in color and 3.3 cm × 2.8 cm in size. Microscopically, the tumor cells were spindle-shaped and had a palisading arrangement with no atypia, which are results compatible with a benign tumor. Both hypercellular and hypocellular areas were visible. Immunohistochemically, the tumor cells were strongly positive for S-100 protein. The tumor was definitively diagnosed as a schwannoma of the pancreatic neck and body. The patient was followed for 72 mo and has been doing well without any complications.

A Case of Pancreatic Schwannoma Diagnosed Preoperatively by Endoscopic Ultrasonography-Guided Fine Needle Aspiration and Treated with Laparoscopic Surgery

Background: Pancreatic tumors are often difficult to diagnose in atypical cases, and a pancreatic schwannoma is very rare. We present a case of pancreatic schwannoma with calcification diagnosed preoperatively by endoscopic ultrasonography (EUS)-guided fine needle aspiration (FNA) and treated with laparoscopic distal pancreatectomy.

Presentation: A 72-year-old-woman was admitted to our hospital due to a 6 × 4.5 cm large tumor in the pancreatic tail. Imaging modalities revealed that the tumor was hypovascular and gradually enhanced with calcification, but was without cystic lesions. EUS revealed the tumor had a clear boundary with a low echoic mass. EUS-FNA was performed and spindle-shaped cells that were immunopositive for S-100 and negative for c-kit, CD34, and desmin were detected, resulting in a diagnosis of schwannoma. Laparoscopic distal pancreatectomy with splenectomy was safely performed without recurrence for a year.

Conclusions: Schwannoma is very rare; however, characteristics of the tumor, such as calcification, can help the diagnosis and, if possible, EUS-FNA should be performed for an appropriate treatment decision.

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

BACKGROUND

Pancreatic 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 PRESENTATION

A 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.

CONCLUSIONS

Although 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.

A case of pancreatic schwannoma showing increased FDG uptake on PET/CT

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Pancreatic schwannoma is rare and preoperative diagnosis is difficult due to the lack of specific symptoms, radiological characteristics and tumor markers.

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Incidental detection of pancreatic schwannoma is predicted to increase due to the widespread use of CT and MRI. It is important to take into account this tumor in the differential diagnosis of pancreatic tumors.

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We should be aware that FDG-PET/CT shows abnormal accumulation in a benign pancreatic schwannoma.

Introduction

Schwannomas are neoplasms originating from Schwann cells in nerve sheath, but pancreatic schwannomas are rare.

Presentation of case

A 59-year-old female incidentally pointed out a 2-cm-sized solid mass in the pancreas head by computed tomography (CT) which was performed for other reasons. Magnetic resonance imaging (MRI) showed a mass with hypointensity on T1-weighted images and a heterogenous hyperintensity on T2-weighted images. Magnetic resonance cholangiopancreatography (MRCP) showed no abnormal findings in the main pancreatic duct. The mass of the pancreas head showed a significantly increased uptake on fluorin-18 fluorodeoxyglucose positron emission tomography CT (FDG-PET/CT). Based on the radiological findings, a malignant potential tumor was preliminarily considered. Subtotal stomach-preserving pancreatoduodenectomy (SSSPD) was performed to make a definite diagnosis. The resected specimen showed a well-encapsulated circumscribed mass, measuring 2.0 cm, in the pancreas head. Histopathological examination revealed proliferation of spindle cells showing interlacing and palisading patterns in the tumor. The proliferating cells showed no atypia and few mitoses. Immunohistochemically, the spindle cells were positive for S-100 protein. The Ki67 labeling index was approximately 2%. Based on these findings, a diagnosis of benign schwannoma of the pancreas was made.

Conclusion

Although pancreatic schwannoma is a rare neoplasm, it is important to take into account this tumor in the differential diagnosis of pancreatic tumors. In addition, we should be aware that FDG-PET/CT shows abnormal accumulation in a benign pancreatic schwannoma.

Successful treatment of a pancreatic schwannoma by spleen-preserving distal pancreatectomy

Schwannomas are neurogenic tumors that arise from the neural sheaths of peripheral nerves. These tumors can be located in any area of the human body; the most common locations are the head, neck, trunk and extremities. Pancreatic schwannomas are very rare. Over the past 40 years, only 67 cases of pancreatic schwannomas have been reported in the English literature. Here we present a case of pancreatic schwannoma in a 62-year-old male. The tumor was revealed by ultrasound and computed tomography in the neck and body of the pancreas. An accurate diagnosis was difficult to obtain preoperatively. The patient consented to the performance of a laparotomy, and the mass was found in the neck and body of the pancreas and successfully treated using a spleen-preserving distal pancreatectomy with splenic artery and vein preservation. The procedure has only been reported in one other case of pancreatic schwannoma; here we present the second reported case. Macroscopically, the tumor was well circumscribed, gray-white in color and 3.3 cm × 2.8 cm in size. Microscopically, the tumor cells were spindle-shaped and had a palisading arrangement with no atypia, which are results compatible with a benign tumor. Both hypercellular and hypocellular areas were visible. Immunohistochemically, the tumor cells were strongly positive for S-100 protein. The tumor was definitively diagnosed as a schwannoma of the pancreatic neck and body. The patient was followed for 72 mo and has been doing well without any complications.

Central pancreatectomy for pancreatic schwannoma: A case report and literature review

Schwannomas are mesenchymal tumors originating from Schwann cells in peripheral nerve sheaths. Although the tumor can be located in any part of the human body, the most common locations are the head, neck, trunk and extremities. Pancreatic schwannomas are rare. To our knowledge, only 64 cases of pancreatic schwannoma have been reported in the English literature over the past 40 years. In this paper, we present a pancreatic schwannoma in a 59-year-old female. Ultrasound, computed tomography and magnetic resonance imaging revealed the tumor located in the pancreatic body; however, accurate diagnosis was hard to obtain preoperatively and a pancreatic cystadenoma was preliminarily considered. During laparotomy, the mass was found in the body of the pancreas. An enlarged gallbladder with multiple stones was also observed. We performed central pancreatectomy, end-to-side pancreaticojejunostomy and cholecystectomy. Notably, central pancreatectomy has been reported in only one case prior to this report. The gross specimen showed a mass with a thin capsule, 1.6 cm × 1.1 cm × 1.1 cm in size. Microscopic examination showed that the tumor was mainly composed of spindle-shaped cells with palisading arrangement and no atypia, which is consistent with a benign tumor. Both hypercellular and hypocellular areas were visible. Immunohistochemical staining revealed strongly positive results for protein S-100. Finally, the tumor was diagnosed as a schwannoma of the pancreatic body. Postoperatively, the patient recovered well and left the hospital 6 d later. During the 53-mo follow-up period, the patient remained well and free of complications.