Cystic schwannoma of the pancreas

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.

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.

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.

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.

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.

Solid pancreatic tumors with unilocular cyst-like appearance on CT: differentiation from unilocular cystic tumors using CT

Objective

To describe the computed tomography (CT) features of neuroendocrine tumors (NETs) and solid pseudopapillary tumors (SPTs) with unilocular cyst-like appearance, and to compare them with those of unilocular cystic tumors of the pancreas.

Materials and Methods

This retrospective study was approved by our Institutional Review Board, and informed consent was waived. We included 112 pancreatic tumors with unilocular cyst-like appearance on CT (16 solid tumors [nine NETs and seven SPTs] and 96 cystic tumors [45 serous cystadenomas, 30 mucinous cystic neoplasms, and 21 branch-duct intraductal papillary mucinous neoplasms]). Two radiologists reviewed the CT images in consensus to determine tumor location, long diameter, morphological features, wall thicknesses, ratio of wall thickness to tumor size, wall enhancement patterns, intratumoral contents, and accompanying findings. Fisher's exact test was used to analyze the results.

Results

All 16 solid tumors had perceptible walls (mean thickness, 2.7 mm; mean ratio of wall thickness to tumor size, 7.7%) with variable enhancement. Four NETs and seven SPTs had hemorrhage, calcifications, and/or mural nodules. Six CT findings were specific for solid tumors with unilocular cyst-like appearance: a thick (> 2 mm) wall, uneven thickness of the wall, high ratio of wall thickness to tumor size, hyper- or hypo-attenuation of the wall in the arterial and portal phase, and heterogeneous internal contents. When three or more of the above criteria were used, 100% specificity and 87.5-92% accuracy were obtained for solid tumors with unilocular cyst-like appearance.

Conclusion

A combination of CT features was useful for distinguishing solid tumors with unilocular cyst-like appearance from unilocular cystic tumors of the pancreas.

Pancreatic schwannoma: A case report and review of the literature

Schwannoma or neurilemmoma is a well-defined, benign tumor, which arises from neural crest cells and surrounds the nerve sheath. It is rare neoplasm that is typically found in the extremities, such as the thorax, head, neck, pelvis and rectum. Schwannoma localized to the pancreas is particularly rare and only a limited number of cases have been reported in the literature to date. The present study reports the case of a 30-year-old male with pancreatic schwannoma presenting with weight loss and abdominal pain. Pancreatic schwannoma was diagnosed using magnetic resonance imaging and ultrasonography-guided biopsy, which was followed by a duodenopancreatectomy. Although pancreatic schwannomas are rare, they must be considered during the differential diagnoses of cystic pancreatic masses.

Pancreatic tail schwannoma in a 44-year-old male: a case report and literature review

Pancreatic schwannomas are exceedingly uncommon neoplasms. According to a recent study in 2012, less than 50 cases of pancreatic schwannoma have been described in the English literature over the past thirty years. The vast majority of pancreatic schwannomas take place in the head and body of pancreas, respectively. Herein, we report the case of pancreatic tail ancient schwannoma in a 44-year-old man who presented with a 4-month history of epigastric pain. On physical examination, epigastric region was moderately tender to palpation without evidence of a palpable mass. All laboratory tests were normal. Contrast-enhanced computed tomography (CT) scan showed a 9.2 × 9.5 × 11.5 cm, huge, and well-defined left suprarenal mass arising either from adrenal gland, pancreas, or retroperitoneum. The mass demonstrated mild heterogeneous enhancement with central cystic/necrotic area. No evidence of distant metastasis was identified. At laparoscopy, the mass was noticed to originate from pancreatic tail. Patient underwent surgical resection of pancreatic tail. Microscopic and immunohistochemical examination of the pancreatic tail specimen showed ancient schwannoma. Patient received no adjuvant therapy. At a postoperative 6-month followup, patient was completely asymptomatic and CT scan imaging showed no evidence of tumor recurrence. Moreover, a literature review on pancreatic schwannomas is presented.

Primary pancreatic cystic neoplasms of the pancreas revisited. Part IV: rare cystic neoplasms

Primary pancreatic cystic neoplasms are being recognized with increasing frequency due to modern imaging techniques. In addition to the more common cystic neoplasms-serous cystadenoma, primary mucinous cystic neoplasm, and intraductal papillary mucinous neoplasm-there are many other less common neoplasms that appear as cystic lesions. These cystic neoplasms include solid pseudopapillary neoplasm of the pancreas (the most common rare cystic neoplasm), cystic neuroendocrine neoplasm, cystic degeneration of otherwise solid neoplasms, and then the exceedingly rare cystic acinar cell neoplasm, intraductal tubular neoplasm, angiomatous neoplasm, lymphoepithelial cysts (not true neoplasms), and few others of mesenchymal origin. While quite rare, the pancreatic surgeon should at the least consider these unusual neoplasms in the differential diagnosis of potentially benign or malignant cystic lesions of the pancreas. Moreover, each of these unusual neoplasms has their own natural history/tumor biology and may require a different level of operative aggressiveness to obtain the optimal outcome.

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

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.

Solid tumors of the pancreas can put on a mask through cystic change

Background

Solid pancreatic tumors such as pancreatic ductal adenocarcinoma (PDAC), solid pseudopapillary tumor (SPT), and pancreatic endocrine tumor (PET) may occasionally manifest as cystic lesions. In this study, we have put together our accumulated experience with cystic manifestations of various solid tumors of the pancreas.

Methods

From 2000 to 2006, 376 patients with pancreatic solid tumor resections were reviewed. Ten (2.66%) of these tumors appeared on radiological imaging studies as cystic lesions. We performed a retrospective review of medical records and pathologic findings of these 10 cases.

Results

Of the ten cases in which solid tumors of the pancreas manifested as cystic lesions, six were PDAC with cystic degeneration, two were SPT undergone complete cystic change, one was cystic PET, and one was a cystic schwannoma. The mean tumor size of the cystic portion in PDAC was 7.3 cm, and three patients were diagnosed as 'pseudocyst' with or without cancer. Two SPT were found incidentally in young women and were diagnosed as other cystic neoplasms. One cystic endocrine tumor was preoperatively suspected as intraductal papillary mucinous neoplasm or mucinous cystic neoplasm.

Conclusions

Cystic changes of pancreas solid tumors are extremely rare. However, the possibility of cystic manifestation of pancreas solid tumors should be kept in mind.

Rare asymptomatic presentations of schwannomas in early adolescence: three cases with review of literature

INTRODUCTION

Schwannoma also known as Neurilemoma is a benign neoplasm of the Schwann Cells of the neural sheath. They are usually found to occur in the extremities, but can also be found in the trunk, head and neck, pelvis, and rectum. It is seldom painful and usually remains small. It has no potential for malignancy unless the patient has multi-neural tumours. It usually presents as a slowly enlarging painless nodule somewhat movable beneath the surface, rarely becomes larger than 2cm in diameter and is most frequently diagnosed in 25-55 yrs of age.

PATIENTS AND METHODS

We report three rare, asymptomatic presentations of schwannomas at adolescent age, in the back, pancreas and in the cervical region with a review of the available literature.

CONCLUSION

Despite the rarity of the presentations, as encountered by us, similar swellings in the adolescent age group can be schwannomas and can be adequately managed surgically alone. This is what should be borne in mind, for 'what the mind knows is what the eyes see'.

Malignant schwannoma of the pancreas involving transversal colon treated with en-bloc resection

Pancreatic schwannoma is a very uncommon tumor of the pancreas, with only 27 cases reported. Most pancreatic schwannomas are benign, with only four malignant tumors reported. We describe a case of giant malignant schwannoma of the pancreatic body and tail, which involved the transverse colon. The tumor was treated successfully with en bloc distal splenopancreatectomy and colon resection. This is believed to be the first reported radical operation for malignant schwannoma of the pancreatic body, with infiltration of the transverse colon, with excellent long-term results. The patient is alive and well 28 mo after the operation. The authors conclude that pancreatic schwannomas should be considered in the differential diagnosis of cystic neoplasms of the pancreas, although the diagnosis can only be confirmed by microscopic examination. In the case of the benign tumors, local excision is adequate, but in the case of malignant schwannoma, oncological standards must be fulfilled.

Pancreatic schwannoma: literature review

Pancreatic schwannoma is a rare neoplasm. Accurate preoperative diagnosis remains difficult, but computed tomography (CT) scanning and magnetic resonance imaging (MRI) help to establish the diagnosis, and definitive diagnosis requires immunohistochemical examination. Cystic pancreatic schwannomas should be considered in the differential diagnosis of cystic neoplasms and pseudocysts. Simple enucleation may be adequate for pancreatic schwannoma. In this report, we examine a case of benign pancreatic schwannoma in a 56-year-old woman. She was being evaluated for an ovarian teratoma, and an 8-cm cystic mass was incidentally found in the head of the pancreas. She underwent a pylorus preserving Whipple procedure with bilateral oopherectomy. Only 37 cases have been reported in the English literature. We present a thorough review with an emphasis on the clinical presentation, diagnostic modalities, and treatment options in the management of this rare clinical entity.

Pancreatic cysts: pathologic classification, differential diagnosis, and clinical implications

CONTEXT

Cystic lesions of the pancreas are being recognized with increasing frequency and have become a more common finding in clinical practice because of the widespread use of advanced imaging modalities and the sharp drop in the mortality rate of pancreatic surgery. Consequently, in the past 2 decades, the nature of many cystic tumors in this organ has been better characterized, and significant developments have taken place in the classification and in our understanding of pancreatic cystic lesions.

OBJECTIVE

To provide an overview of the current concepts in classification, differential diagnosis, and clinical/biologic behavior of pancreatic cystic tumors.

DATA SOURCES

The authors' personal experience, based on institutional and consultation materials, combined with an analysis of the literature.

CONCLUSIONS

In contrast to solid tumors, most of which are invasive ductal adenocarcinomas with dismal prognosis, cystic lesions of the pancreas are often either benign or low-grade indolent neoplasia. However, those that are mucinous, namely, intraductal papillary mucinous neoplasms and mucinous cystic neoplasms, constitute an important category because they have well-established malignant potential, representing an adenoma-carcinoma sequence. Those that are nonmucinous such as serous tumors, congenital cysts, lymphoepithelial cysts, and squamoid cyst of pancreatic ducts have no malignant potential. Only rare nonmucinous cystic tumors that occur as a result of degenerative/necrotic changes in otherwise solid neoplasia, such as cystic ductal adenocarcinomas, cystic pancreatic endocrine neoplasia, and solid-pseudopapillary neoplasm, are also malignant and have variable degrees of aggressiveness.

Case of cystic schwannoma

Schwannoma is a well-defined tumor arising from the nerve sheath. It may present as a solitary mass in any part of the body, but is more commonly seen in the head, neck and extremities. We describe a 32-year-old female patient with a small dermal nodule on the forehead, which was 2 cm in diameter, round and of a cystic nature. Microscopic examination revealed that it consisted of compact spindle cells arranged partly in short bundles or a fascicular pattern with outstanding cystic degeneration manifested as a large, unilocular cavity in the center of the tumor tissue. The tumor cells were positive for S-100 protein and negative for epithelial membrane antigen (EMA), while the tumor capsule was positive for EMA. There was no S-100-positive membrane-like structure lining the cyst wall.

Rare presentation of pancreatic schwannoma: a case report

Introduction

Schwannoma is a rare tumor among pancreatic neoplasms. Schwannomas vary in size, and most of them are cystic, mimicking pancreatic cystic lesions. Generally, a definitive diagnosis is made at the time of histological analysis. The mainstay treatment is surgical resection.

Case presentation

We report an unusual presentation of pancreatic schwannoma with abdominal pain and several episodes of cholangitis in a 54-year-old Caucasian (Iranian) man. The condition was not diagnosed pre-operatively and Whipple's procedure was performed.

Conclusion

Pancreatic schwannoma is an important clinical entity to include in the differential diagnosis of pancreatic lesions. Pre-operative diagnosis is difficult but computed tomographic findings may be helpful. The tumor may also have atypical and rare presentations, such as cholangitis and weight loss. For benign tumors, simple enucleation is usually adequate, whereas malignant tumors require standard oncological resection.

Giant cystic intradural schwannoma in the lumbosacral region: a case report

We report a case of a giant cystic intradural schwannoma of the lumbosacral region in a 30- year-old man who presented with a 2-year history of non-specific lower back pain. Lateral radiographs demonstrated scalloping of the posterior wall of L5 and the upper sacrum. Magnetic resonance imaging revealed a 12 x 2.3-cm intradural multi-septated cystic lesion extending from L3 to S2 with predominant hypointense signal on T1-weighted images and a mixed signal on T2-weighted images. There was heterogeneous rim enhancement of the retrosacral portion of lesions following the administration of gadolinium contrast. The tumour was completely excised. Histological investigation confirmed the diagnosis of cystic schwannoma with alternating hypercellular (Antoni A) and hypocellular (Antoni B) areas in a fibrillar background. The patient had complete relief of symptoms and remained asymptomatic after 2 years of follow-up.

Pancreatic schwannoma: report of a case

Among pancreatic neoplasms, pancreatic schwannoma is quite rare. We report a case of solitary pancreatic schwannoma, plus a literature review of this tumor. A 71-year-old woman was diagnosed by abdominal ultrasonography as having a pancreatic tumor and was hospitalized in our department at Kumamoto University Hospital on January 26, 2006. Abdominal computed tomography, magnetic resonance imaging, and endoscopic ultrasonography all showed this tumor, which was located in the body of the pancreas, to have cystic and solid components, and with a septum in the cystic part of the lesion. The tumor, preoperatively identified as a mucinous cystic neoplasm, was clearly separated from the normal pancreatic parenchyma. We performed a spleen-preserving distal pancreatectomy with a lymph node dissection on February 7, 2006. A histopathological examination of the resected specimen by means of hematoxylin and eosin revealed the tumor to consist of two parts: one with a compact spindle cell pattern (Antoni type A), and the other showing degeneration of fat (Antoni type B). We also found positive results for immunohistochemical staining for S-100 and vimentin. These findings confirmed the tumor's classification as a pancreatic schwannoma.

Cystic pancreatic schwannoma in a 46-year-old man

Pancreatic schwannomas are a rare benign mesenchymal neoplasm of the pancreas. They are thought to arise from the epineurium of either autonomic sympathetic or parasympathetic fibers, which course through the pancreas with the vagus nerve. Large pancreatic schwannomas often undergo cystic change, which causes them to be often confused with other more common cystic pancreatic neoplasms preoperatively. The radiological, histologic, and immunohistochemical findings of pancreatic schwannomas are consistent with those of neoplasms found in other sites. Treatment is by surgical resection, and the prognosis is excellent. The awareness and, to some extent, knowledge of less common tumors in the pancreas are needed to achieve the diagnosis. We discuss the clinical and pathologic features and differential diagnosis of cystic pancreatic tumors.

Cystic neoplasms of the exocrine pancreas

The increasing use of radiological imaging has led to greater detection of small and asymptomatic cystic lesions of the pancreas. Most are resectable, but not all are neoplastic. This review provides an update on the histopathology, immunohistochemistry, molecular biology, pathogenesis and management of cystic neoplasms of the exocrine pancreas. These include the serous, the mucinous cystic, the intraductal papillary mucinous and the solid pseudopapillary neoplasms. Recently reported variants are described and very rare cystic variants of other pancreatic epithelial and mesenchymal neoplasms are briefly mentioned.

Analysis of 50 cases of pancreatic schwannoma

AIM: To analyze the incidence of pancreatic schwannoma and investigate its diagnosis and treatment.

METHODS: A retrospective study of clinical data from 50 patients with pancreatic schwannoma.

RESULTS: The lesion was located in the head of pancreas in 25 patients, the body in 9 (18%), the body and tail in 6, the tail in 5, the head and body in 2, the neck in 1, and the location was not specified in 2 patients. Solid tumors were found in 18 patients, cystic tumors in 25, and the nature of the tumor was not specified in 7 patients. Forty-nine patients received operative therapy. Thirteen patients underwent a Whipple operation, 12 distal pancreatectomy, 12 local resection, 8 simple enucleation, and in 2 patients the surgical procedure was not specified. The tumor in 1 patient was unresectable. One patient underwent biopsy. One patient refused surgery. The longest follow-up was 9 years, and there have been no reports of local recurrence or metastasis.

CONCLUSION: Preoperative diagnosis of pancreatic schwannoma is difficult. Definite diagnosis depends on pathological examination. Benign tumors can be effectively treated by local excision but those with malignancy should be treated by simple enucleation. Intraoperative frozen sections are useful for determining which kind of operation should be undertaken.

Cystic lesions of the pancreas

Although cystic tumors of the pancreas are relatively rare, they constitute an increasingly important category. Advances in imaging and interventional techniques and the sharp drop in the mortality rate of pancreatic surgery have rendered pancreatic biopsies and resections commonplace specimens. Consequently, in the past two decades, the nature of many cystic tumors in this organ has been better characterized. The names of some existing entities were revised; for example, what was known as papillary-cystic tumor is now regarded as solid-pseudopapillary tumor. New entities, in particular, intraductal papillary mucinous neoplasm and its variants, such as oncocytic and intestinal subtypes were recognized. The importance of clinical and pathologic correlation in the evaluation of these lesions was appreciated, in particular, with regards to the multifocality of these lesions, their association with invasive carcinomas, and thus their 'preinvasive' nature. Consensus criteria for the distinction of these from the ordinary precursors of adenocarcinoma, the pancreatic intraepithelial neoplasia, were established. The definition of mucinous cystic neoplasms was refined; ovarian-like stroma has now become almost a requirement for the diagnosis of mucinous cystic neoplasia, and defined as such, the propensity of these tumors to occur in perimenopausal women became even more striking. The validity and clinical value of classifying the pancreatic cysts of mucinous type as adenoma, borderline, CIS and invasive have been established. Related to this, the importance of thorough sampling in accurate classification of these mucinous lesions was recognized. Greater accessibility of the pancreas afforded by improved invasive as well as noninvasive modalities has also increased the detection of otherwise clinically silent cystic tumors, which has led to the recognition of more innocuous entities such as acinar cell cystadenoma and squamoid cyst of pancreatic ducts. As the significance of the cystic lesions emerged, cystic forms of otherwise typically solid tumors were also better characterized. Thus, significant developments have taken place in the classification and our understanding of pancreatic cystic tumors in the past few years, and experience with these lesions is likely to grow exponentially in the coming years.

Primary intratracheal neurilemmoma in children: case report and literature review

A 9-year-old girl was admitted because of recurrent cough, dyspnea, and tachypnea for over 3 months, which had become worse for the preceding week. A chest X-ray revealed a mass in the lumen of the trachea. Fiberoptic bronchoscopy confirmed a polypoid mass in the upper trachea 3 cm under the vocal cords, with a 1.5-cm diameter that occluded approximately 70% of the lumen. Endoscopic excision of the neoplasm was performed with rigid bronchoscopy. Results of immunolabeling, which was positive for S-100 protein and vimentin, demonstrated a benign neurilemmoma. Clinical symptoms and signs improved after the tumor was removed. Intratracheal neurilemmoma is an extremely rare neoplasm, and only 34 cases were previously reported worldwide. The most common presentation is airway obstruction. Preoperative diagnosis is difficult, and radiographic techniques are helpful for diagnosis. Bronchoscopy is recommended for diagnosis, biopsy, and resection of the tumor. Long-term follow-up after simple enucleation is required.

Pancreatic benign schwannoma treated by simple enucleation: case report and review of literature

Benign schwannoma in the pancreatic head is very rare, with only 11 patients being reported in the English literature from a Medline search. Furthermore, only 1 of them was treated by simple enucleation. Herein, we present another enucleation case: a 71-year-old male patient with a 1.5 x 1.2-cm low-density mass, mimicking a cystic lesion located at the head of pancreas, which was detected by computed tomography. This tumor failed to be discovered by abdominal ultrasound. At laparotomy, a solid mass 1 cm in diameter was identified; it was the smallest one in the pancreatic head according to the 11 previous reported cases. No complications were found after the operation. At 10-month follow-up, the patient remains asymptomatic and has no signs of recurrence. The data of the 12 patients indicated that simple minimal invasive enucleation for small benign schwannoma in the pancreatic head was feasible and safe; early detection and early treatment of the tumor were helpful in increasing the ratio of enucleation and avoiding a very invasive Whipple operation.

Imaging features and treatment of an intradural lumbar cystic schwannoma

Spinal schwannomas are frequently observed among patients treated in a reference neurosurgery center. Cystic spinal schwannomas, however, are very scantly found. Due to its indolent behavior and benign course, the diagnosis of schwannomas may pose a challenge to the care giver, and the imaging findings can be misleading. In this article, we illustrate an example of a pauci-symptomatic 55 year-old male patient whose complaint was solely a non specific lumbar pain. Investigation revealed a large cystic lesion comprising the lower lumbar intradural space. He was then treated with microneurosurgical technique involving complete removal of the tumor and reconstruction of the duramater. Histological and immunohystochemical diagnosis were consistent with cystic schwannoma. The patient presented with complete recovery of his symptom. In this article we aim to emphasize the clinical presentation and treatment of lumbar spine schwannomas, and to illustrate the imaging findings within this uncommon case.

Pancreatic schwannoma: CT findings

Schwannomas of the pancreas are rare tumors. We report a case of solitary schwannoma of the pancreas without von Recklinghausen disease. A 72-year-old man underwent routine abdominal ultrasound before cholecystectomy because of chronic cholecystitis and multiple gallstones, and ultrasound showed a small solitary tumor in the pancreas. Spiral computed tomography showed a 1.0-cm, well-defined homogeneous hypodense lesion with mild inhomogeneous enhancement and peripheral enhancement at the junction between the head and body of the pancreas. These computed tomographic findings are different from those in previous reports.

Benign schwannoma of the pancreas

Reported cases of intrapancreatic schwannomas have recently increased in the literature. However, none of these cases were diagnosed clearly as schwannoma preoperatively. We herein describe the clinicopathologic findings of a solitary benign schwannoma occurring in the head of the pancreas. Additionally, the differential diagnosis versus other cystic- and solid-appearing pancreatic masses is briefly discussed.

Clinical characteristics, treatment, and outcome of pancreatic Schwannomas

This article involves the study of a patient with a rare benign schwannoma in the body of the pancreas. After reviewing 39 patient cases previously reported in the literature, a discussion of the schwannoma with regard to clinical presentation, diagnosis, and treatment is examined. A review of the patient's chart was performed along with a review of the literature using a Medline search. Translations were performed whenever necessary. There are 23 reports of 29 patient cases of pancreatic schwannomas in English and European literature and one report of 10 patient cases in the Japanese literature. The mean age was 57.75 years (range 32-89) and the male-to-female (M:F) ratio was 17:23. The mean reported size was 8.79 cm. The lesion was located in the head in 16 patients (40%), the body in 8 patients (20%), the body and tail in 8 patients (20%), the tail in 6 patients (15%), the head and body in 1 patient (2.5%), and the location was not specified in 1 patient (2.5%). Of the English and European patients, 11 out of 30 patients (36.7%) exhibited solid tumors and 14 out of 30 patients (46.7%) exhibited cystic tumors. The majority of the tumors (35 out of 40) were benign, but there were five reported malignancies. There were no deaths or recurrences reported with a follow-up of 18.68 months +/- 24.09 (range 3-108 months). Pancreatic schwannomas are rare, and the preoperative diagnosis is difficult. Intraoperative frozen section can confirm the diagnosis of a benign schwannoma. Enucleation of the tumor from the surrounding parenchyma is recommended, if possible. Patients undergoing resection indicate an excellent long-term prognosis.

Cystic neoplasms of the pancreas and tumor-like lesions with cystic features: a review of 418 cases and a classification proposal

Although cystic neoplasms and lesions of the pancreas are rare, they have attracted a great deal of attention because of their potential curability. Since, in recent years, several new entities have been identified, the relative frequency of the tumors and their classification need to be reevaluated. In a series of 1454 tumorous lesions of the pancreas collected between 1971 and 2003 in our surgical pathology files and consultation files, all cystic pancreatic neoplasms and tumor-like lesions were identified and typed both histologically and immunohistochemically. There were 418 cases (29%) showing cysts with a diameter ranging between 0.5 cm and 27 cm. Most common were solid pseudopapillary neoplasms (21%) and intraductal papillary-mucinous neoplasms (18%). When only the cystic neoplasms and lesions that had been resected in a single institution were considered, intraductal papillary mucinous neoplasms were the most frequent cystic neoplasms, while solid pseudopapillary neoplasms took fifth place behind ductal adenocarcinomas with cystic features, serous cystic neoplasms and mucinous cystic neoplasms. The most frequent cystic tumor-like lesions were pancreatitis-associated pseudocysts. New and rare entities that have recently been identified are mucinous nonneoplastic cysts, acinar cell cystadenomas and cystic hamartomas. Bearing in mind that figures from referral centers such as ours may be biased regarding the relative frequency of lesions, we concluded from our data that intraductal papillary-mucinous neoplasms are the most frequently occurring pancreatic cystic neoplasms, rather than solid pseudopapillary neoplasms. It was possible to classify all cystic lesions encountered in our files or described in the literature in a new system that distinguishes between neoplastic and nonneoplastic lesions, with further subdivisions into epithelial (adenomas, borderline neoplasms and carcinomas) and nonepithelial tumors. This classification is easy to handle and enables a distinction on the basis of clinical behavior and prognosis.