Pancreatic Schwannoma: report of a case

Pancreatic schwannoma: Case report, clinico-pathologic correlation, and review of the literature

Schwannomas are common peripheral nerve sheath tumors that typically occur on the head, neck, trunk, or extremities. Intra-abdominal schwannomas, however, are rare. We describe a young woman who presented for imaging evaluation of suspected nephrolithiasis and was incidentally found to have a schwannoma centered within the pancreatic parenchyma. In addition, we detail the clinical, imaging, and histopathologic features of pancreatic schwannoma and summarize diagnosis and management of this rare clinical entity.

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.

Pancreatic Schwannoma Diagnosed by Endoscopic Ultrasound-guided Fine-needle Aspiration

A schwannoma is a tumor originating from Schwann cells. It is occasionally observed in the abdominal viscera in the form of a submucosal tumor derived from the gastric or duodenal muscularis propria. To date, only a few studies have reported on pancreatic schwannomas. Furthermore, very few patients are preoperatively diagnosed with pancreatic schwannoma because of the lack of established imaging characteristics distinguishing this type of schwannoma from other conditions. We herein report the first English publication of pancreatic schwannoma in which surgery was avoided because a pathological diagnosis was made solely on the basis of endoscopic ultrasound-guided fine-needle aspiration findings.

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.

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

Pancreatic schwannoma is a very rare tumor that tends to be confused with other pancreatic tumors preoperatively. We report a case of schwannoma of the pancreatic head. A 40-year-old woman was admitted to our hospital for treatment of a pancreatic tumor which was found by medical checkup. It was a well-defined solid tumor exhibiting heterogeneous enhancement with some necrotic foci on contrast-enhanced computed tomography (CT) and on magnetic resonance imaging (MRI). Angiography and CT during arteriography revealed the main feeding arteries of the tumor to be the posterior and anterior superior pancreaticoduodenal arteries. Fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) showed accumulation of FDG in the tumor with a maximum standardized uptake value of 3.6. We diagnosed a solid pseudopapillary neoplasm or a pancreatic neuroendocrine tumor preoperatively and performed pylorus-preserving pancreaticoduodenectomy. The tumor had well a well-defined capsule and was composed of a large solid portion containing spindle cells and a smaller hemorrhagic portion containing hypocellular stroma, and diagnosed as pancreatic schwannoma by immunohistochemistry. In this case, CT during arteriography was useful in determining the origin of the tumor. MRI reflected the pathological features of the tumor. The most important finding was that FDG-PET showed abnormal accumulation of FDG in the benign pancreatic schwannoma.

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.

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.

Single-port transumbilical laparoscopic excision of retroperitoneal schwannoma mimicking a nonfunctional endocrine tumor in the body of the pancreas: a case report

Schwannomas are benign tumors that arise from neural sheath Schwann cells. Solitary benign schwannoma is generally located in the head and neck and is a rare neoplasm among the tumors of the retroperitoneal space. Reports of laparoscopic excision of retroperitoneal schwannomas have recently been on the increase. However, few cases of single-port laparoscopic excision of these tumors have been reported. Moreover, there are no reports of single-port excision of schwannomas attached to the body of pancreas and around the splenic vessels. This is the first report of a schwannoma lying adjacent to the body of the pancreas between the splenic artery and vein that was excised by single-port laparoscopic surgery. The most notable aspect of our procedure is the use of bipolar forceps. Single-port laparoscopic excision using bipolar forceps is a feasible and safe procedure for retroperitoneal solitary tumors, even when they are close to the splenic artery and vein.

Microcystic/reticular schwannoma of the pancreas: a potential diagnostic pitfall

Schwannomas occurring in the pancreatic head are rare benign non-recurring mesenchymal neoplasms and are reported to show classic morphologic features. Herein we report a case of a 62 year old male presenting with a 5 cm mass in the pancreatic head encasing the portal vein and the truncus coeliacus. Preoperative fine needle aspiration revealed malignant tumour cells consistent with a moderately differentiated adenocarcinoma. A Whipple surgery was performed after palliative chemotherapy. Histological evaluation revealed a multinodular unencapsulated tumour with focal infiltration into pancreas parenchyma and a striking microcystic/reticular growth pattern. Anastomosing and intersecting strands of spindle cells with eosinophilic cytoplasm set in a myxoid partly collagenous stroma were observed. The tumour cell nuclei were round oval and tapered and showed inconspicuous small nucleoli. Degenerative nuclear atypia was seen. Mitotic activity was sparse (1/50 HPF). Pleomorphism or necrosis was absent. The tumour cells showed strong nuclear and cytoplasmic positivity for S-100 protein, and focal positivity for glial fibrillary acidic protein. The diagnosis of a microcystic/reticular schwannoma was made. The awareness of and, to some extent, the knowledge about this rare tumour are needed to achieve the correct diagnosis and to avoid confusion, especially with malignant pancreatic neoplasms.

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 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.

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.

MRI features of a pancreatic schwannoma

A case of a pancreatic schwannoma is presented. The patient, a previously healthy woman, is hospitalized with the diagnosis of purulent pleuritis. Ultrasonography (US) of the abdomen shows a 3-cm mass in the head of the pancreas. Magnetic resonance imaging (MRI) reveals, in T1-weighted sequences, the mass to be hypointense, and an early and persistent enhanced signal is noted following the administration of gadolinium. In T2-weighted fat saturation sequences, the lesion appears markedly hyperintense. A duodenopancreatotomy is performed, and the pathologic specimen demonstrates a schwannoma of the pancreas with Antoni A pattern.

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.

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.

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.

Differential diagnosis of non-epithelial tumors of the pancreas: malignant non-epithelial pancreatic tumor with focal pigmentation

Non-epithelial tumors only rarely affect the pancreas. In this report, we describe a malignant non-epithelial tumor with combined characteristics of malignant peripheral nerve sheath tumor (MPNST) and malignant melanoma. To more closely define the differential diagnosis of MPNST with focal pigmentation versus metastatic melanoma resembling MPNST, the tumor was investigated using histomorphology, immunohistochemistry, electron microscopy, and comparative genomic hybridization. As a result, from these analyses and from clinical findings, the diagnosis of a pancreatic MPNST with focal pigmentation was favored. However, the diagnosis of a malignant melanoma or a composite tumor could not be definitely ruled out, due to the considerable morphological and genotypical overlap between both entities, which can be explained by the close histogenetic relationship between both tumor entities.

Imaging of uncommon tumors of the pancreas

In this article, the radiological manifestations of a variety of uncommon tumors of the pancreas are illustrated, with emphasis placed on their appearance at helical CT. Islet cell tumors, because of their vascularity, typically present as masses that are hyperattenuating to the normal pancreas at dual-phase helical CT. Lymphomas appear as hypoattenuating focal lesions or can diffusely infiltrate the gland. Absence of biliary tree dilatation, despite the presence of a bulky tumor, or associated extensive retroperitoneal adenopathy should offer clues to the diagnosis. Pancreatic metastases are usually seen in patients with advanced cancers, although isolated metastases from renal cell carcinoma can occurs years after the original tumor; such patients may benefit from surgical resection. Finally, the appearance of some rare neoplasms of mesenchymal origin is discussed.