Solid and Pseudopapillary Tumor of the Pancreas—Review and New Insights Into Pathogenesis

Solid pseudopapillary tumor of the pancreas and concomitant urogenital malformations in a young woman

Abstract

Solid pseudopapillary tumor (SPT) of the pancreas is a rare pancreatic tumor with low malignant potential. It occurs characteristically more often in young women. SPT associated with extra- and pancreatic anomalies are occasionally reported. Here we report a case of pancreatic SPT with concomitant urogenital malformations including solitary kidney and uterus didelphys in a 25-year-old woman. The patient underwent central pancreatectomy, and SPT was confirmed with pathological results. Recurrence or metastasis was not found after 14 months of follow-up.

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Clinicopathologic features and surgical outcome of solid pseudopapillary tumor of the pancreas: analysis of 17 cases

BACKGROUND

We summarize our experience of the diagnosis, surgical treatment, and prognosis of solid pseudopapillary tumors (SPTs).

METHODS

We carried out a retrospective study of clinical data from a series of 17 patients with SPT managed in two hospitals between October 2001 and November 2011.

RESULTS

All of the 17 patients were female and the average age at diagnosis was 26.6 years (range 11 years to 55 years). The tumor was located in the body or tail in ten patients, the head in five patients, and the neck in two patients. The median tumor size was 5.5 cm (range 2 cm to 10 cm). All 17 patients had curative resections, including seven distal pancreatectomies, five local resections, four pancreaticoduodenectomies, and one central pancreatectomy. Two patients required concomitant splenic vein resection due to local tumor invasion. All patients were alive and disease-free at a median follow-up of 48.2 months (range 2 to 90 months). There were no significant associations between clinicopathologic factors and malignant potential of SPT. Ki-67 was detected in three patients with pancreatic parenchyma invasion.

CONCLUSIONS

The SPT is an infrequent tumor, typically affecting young women without notable symptoms. Surgical resection is justified even in the presence of local invasion or metastases, as patients demonstrate excellent long-term survival. Positive immunoreactivity for Ki-67 may predict the malignant potential of SPTs.

Three female familial cases of solid pseudopapillary tumors with a protease serine 1 gene mutation

Solid pseudopapillary tumors (SPTs) are a rare pancreatic neoplastic lesion. Familial aggregation has not been reported in this disease. The objectives of this study were to report the history, clinicopathological features, and gene mutations of 3 familial cases of SPT. Three female cases of SPT presented in 1 family. Eight family relatives, 5 healthy volunteers, and 8 patients with SPT acted as controls. Histological examination and immunohistochemistry were performed on the surgical tumor specimens. Polymerase chain reaction-single-strand conformation polymorphism and gene sequencing were performed on genomic DNA extracted from blood. All 3 patients underwent surgical treatment, 2 patients died (3 months and 5 months after surgery), whereas neither recurrence nor metastasis was observed in the other patient during 2-year follow-up. The tumors from the 3 cases had identical immunoreactivity to a series of molecular markers. A Leu104Val mutation of protease serine 1 (PRSS1) was observed in the familial patients and 2 healthy male family members; no β-catenin or adenomatous polyposis coli mutations were detected in the familial cases. This study indicates the possibility of genetic involvement in the pathogenesis of SPT. Family history may be a positive predictive factor for malignancy in SPT.

Cystic "feminine" pancreatic neoplasms in men. Do any clinical alterations correlate with these uncommon entities?

INTRODUCTION

Mucinous cystic neoplasm (MCN) and solid pseudopapillary neoplasm (SPN) of the pancreas are uncommon hormone-related pancreatic tumors (HRPTs) with a clear predominance in young women. This trial aims to investigate the possible association between HRPTs development in males and phenotypic and sex hormone alterations.

METHODS

We performed a retrospective analysis of our database between February 1990 and February 2012. Risk factors for sexual dysfunction were considered exclusion criteria. We investigated secondary sexual characteristics development, sex hormone level and overall sexual dysfunction degree according with the International Index of Erectile Function Questionnaire (IIEF).

RESULTS

We initially identified 25 patients [(MCN: n = 16 (64%); SPN: n = 9 (36%)]. At follow-up, 5 patients were lost, 8 resulted dead and 3 were excluded according to exclusion criteria. We finally enrolled 9 patients (MCN: n = 5; SPN: n = 4). Puberty occurred within physiological age for 7 patients, whereas it was delayed in 2 cases. Three patients revealed mild to moderate sexual dysfunction, along with low testosterone level in two cases. One patient presented hormonal alteration with a normal IIEF score.

DISCUSSION

In this study, the first in literature with similar aim, hormonal and/or sexual dysfunction was present in 4 out of 9 patients affected by HRPT. The rarity of these lesions makes further trials to be needed for reliable conclusions.

Solid pseudopapillary neoplasms of the pancreas: an 18-year experience at a single Japanese Institution

PURPOSE

This study investigated the clinicopathological features and surgical management of solid pseudopapillary neoplasms at a single institution in Japan.

METHODS

Seventeen patients (the largest series in Japan) those underwent surgery for pathologically confirmed solid pseudopapillary neoplasms were retrospectively reviewed.

RESULTS

Sixteen patients were women and their mean age was 34.1 years. Most patients were asymptomatic (n = 11), and the average tumor diameter was 51.8 mm. The most common imaging characteristic was tumors of solid and cystic type (n = 10), which were most commonly located in the pancreatic body (n = 7). All patients underwent surgical exploration, i.e., distal pancreatectomies in 7 patients (laparoscopically performed in 2); middle pancreatectomies, 4; pancreaticoduodenectomies, 4; enucleation, 1; and liver resection, 1. No surgical mortalities occurred, and postsurgical complications occurred in 9 patients. Four patients had malignant tumors. One patient with liver metastases experienced recurrence, which was well controlled by paclitaxel. The remaining patients were disease free at a median follow-up of 51 months.

CONCLUSIONS

Solid pseudopapillary neoplasms can be treated by complete tumor resection with limited resection or a minimally invasive approach when applicable. The combination of surgical resection and chemotherapy may therefore prolong survival, even in malignant cases.

Solid-pseudopapillary neoplasms of the pancreas: clinical and pathological features of 33 cases

PURPOSE

Solid-pseudopapillary neoplasms (SPNs) are rare pancreatic tumors, with a low potential for malignancy. The clinical and pathological features of 33 SPNs were reviewed.

METHODS

This study conducted a retrospective analysis of 33 patients who underwent surgery for a pathologically confirmed SPN from 2000 to 2011.

RESULTS

Thirty of the 33 patients (91 %) were female, and the median age at diagnosis was 29.2 years (range 12-59). The most common symptom was abdominal discomfort with dull pain (58 %). Others included asymptomatic lesions that were only detected incidentally during imaging (21 %), a palpable abdominal mass (15 %) and indigestion (6 %). All 33 patients underwent surgery with a curative intent and 3 (9 %) underwent laparoscopic surgery. The mean diameter of the tumors was 4.9 cm (range 2-15 cm), and they occurred in the head (9, 27 %), neck (5, 15 %), body or tail (19, 58 %) of the pancreas. One patient had lymph node metastases, one patient had portal venous invasion and 8 patients had perineural invasion. The patient follow-up ranged from 4 to 118 months, and 32 patients were alive and well without recurrence. One patient relapsed 10 months after distal pancreatectomy with splenectomy and underwent a second surgery via laparotomy. Unfortunately, the patient died of multiple organ failure 12 days after the second surgery.

CONCLUSION

SPNs are rare neoplasms with malignant potential but excellent prognosis. Adequate surgical resection, including laparoscopic surgery, may therefore be performed safely and is associated with a long-term survival, even in invasive cases.

Rare pancreatic neoplasm: MDCT and MRI features of a typical solid pseudopapillary tumor

Solid pseudopapillary tumor of the pancreas is a rare neoplasm, predominantly observed in young women and with greatest incidence in the second and third decade. It has clinically good behavior, although large at the time of diagnosis. We report the case of a thirty-year-old woman with a giant mass in the pancreas, incidentally discovered during an abdominal ultrasonography. The mass was later investigated by multidetector computed tomography and magnetic resonance imaging. The cystic-solid appearance of the encapsulated lesion suggested to radiologists the possibility of a solid pseudopapillary tumor. Imaging features of this pancreatic neoplasm and differential diagnosis from other cystic pancreatic tumors are discussed in our report, in order to help radiologists and clinicians achieve correct diagnosis and management.

Expression of galectin-3 in pancreatic ductal adenocarcinoma

Galectin-3 influences neoangiogenesis, tumor cell adhesion, and tumor-immune-escape mechanisms. Hence, the expression of galectin-3 in pancreatic ductal adenocarcinoma (PDAC) was evaluated. Galectin-3 expression in PDAC cell lines was proven by the presence of intracellular protein and by release into the supernatant. Furthermore, galectin-3 was found in the majority of human tissue samples. Serum concentrations of galectin-3 in PDAC patients did not differ significantly from healthy donors and did not correlate with established tumor markers. In conclusion, galectin-3 is expressed in PDAC tissues suggesting a role in tumor development; however, no relationship between expression and clinical findings could be established.

Solid pseudopapillary tumor of the pancreas in children: report of a case and review of the literature

Solid pseudopapillary tumor (SPT) of the pancreas is an infrequent neoplasm of low malignant potential, first described by Frantz in 1933 and representing less than 3% of all exocrine tumors. SPT is rare in children, accounting for 6% of all cases and shows different clinical features compared with adults. Here, a pediatric case is reported and a review of the Literature is provided. A 15-year-old girl with a 12 × 14 × 10 cm solid mass growing from the tail and the body of the pancreas, involving spleen, left adrenal gland and kidney, stomach and some bowel loops, was referred for surgical treatment. A distal pancreasectomy with splenectomy was performed. Histopathological examination revealed that the tumor was a 14-cm well-circumscribed solid mass, with pseudopapillary cell architecture, showing strong cellular immunoreactivity for alpha-1 antitrypsin, vimentin, neurone-specific enolase, progesterone receptors and in part to CD10 and CAM 5.2, but not to sinaptofisin and chromogranin. A 24-month post-surgical follow-up after successful surgical resection showed no evidence of recurrent disease. SPT shows different clinical features in childhood. High survival rates can be achieved in most cases, warranting aggressive treatments even in metastatic disease.

Immunohistochemical evaluation of solid pseudopapillary tumors of the pancreas: the expression pattern of CD99 is highly unique

The aim of this study was to investigate CD99 as a new marker to characterize solid pseudopapillary tumors (SPTs), and to determine a specific panel of markers to identify the disease. We analyzed the clinicopathological characteristics and immunohistochemical features of 37 patients with SPT. All 37 tumors displayed intracytoplasmic dot-like immunoreactivity of CD99 in contrast to membranous staining in all pancreatic endocrine tumors and most of acinar cell carcinomas, along with negative immunostaining in ductal carcinomas. In addition, we observed a loss of expression of E-cadherin in all SPTs as well as in some other pancreatic tumors, and aberrant nuclear expression of β-catenin in most SPTs. Our findings demonstrated for the first time that the pattern of CD99 expression was highly specific for distinguishing SPTs from other pancreatic tumors. CD99 combined with E-cadherin/β-catenin and CD10 can be used as a relatively specific expression profile of SPTs.

Solid pseudopapillary tumor of the pancreas: can malignancy be predicted?

BACKGROUND

The objective of this study was to examine the clinicopathologic characteristics of solid pseudopapillary tumors (SPTs) of the pancreas, including the risk factors for disease recurrence and their effects on survival.

METHODS

The medical records of 114 patients who underwent surgery for a pathologically confirmed SPT between January 1995 and December 2007 were reviewed retrospectively.

RESULTS

Of the 114 patients, 98 (86.9%) were female, and the median age was 36 years (range, 11-75). All 114 patients underwent curative intent surgery and 13 (11.4%) underwent laparoscopic surgery. Of the 114 patients, 26 (22.8%) had solid pseudopapillary carcinoma (SPC). There were no differences in any clinical factors between the benign SPT and SPC groups; however, the only 4 recurrences identified were in the SPC group. After follow-up ranging from 11 to 177 months, all 114 patients were alive, with only 4 showing evidence of recurrence. Recurrence was observed in young patients with metastasis at first operation, invasion of an adjacent organ, and a large mass (≥13 cm).

CONCLUSION

Adequate operative resection including laparoscopic surgery is the mainstay of treatment for SPT. Although statistically significant risk factors for recurrence cannot be determined, tumor metastasis at the first operation, invasion of adjacent organ, large tumor size, young patient age, tumor rupture, and inadequate resection may increase the risk of recurrence. Our results demonstrate that long-term survival could be achieved by aggressive operative resection and interventional treatment of recurrent disease.

Minimally invasive (laparoscopic and robot-assisted) approach for solid pseudopapillary tumor of the distal pancreas: a single-center experience

BACKGROUND/PURPOSE

A single-institutional experiences of solid pseudopapillary tumor (SPT) in the distal pancreas were retrospectively reviewed with special reference to a minimally invasive approach.

METHODS

Thirty-five patients with SPT of the distal pancreas treated during the past 20 years were retrospectively evaluated. We divided the patients into 2 groups based on the surgical approach: the laparoscopic/robot-assisted surgery (LR) group and the conventional open surgery (O) group. We reviewed the chronological changes and characteristics of SPT. A comparative analysis of the two groups (LR vs. O) was conducted in terms of perioperative surgical outcomes.

RESULTS

The discovery of relatively small SPTs without symptoms seemed to be increasing (p < 0.05). Eleven of the 35 patients were assigned to the LR group. Ten patients were female and 1 was male, and they had a median age of 32 years (range 24-62 years) and a median tumor size of 3.6 cm (range 1-8.5 cm). Eight patients underwent laparoscopic distal pancreatectomy with or without splenectomy, and the remaining 3 underwent robot-assisted central pancreatectomy with pancreaticogastrostomy. In the comparative analysis of the LR and O groups, smaller tumor size, earlier oral intake, and shorter hospital stay, without increasing morbidity, were noted in the LR group (p < 0.05).

CONCLUSIONS

A minimally invasive (laparoscopic/robot-assisted) approach for SPT of the distal pancreas is thought to be more appropriate than and preferable to conventional open surgery in well-selected patients.

Primary malignant solid pseudopapillary tumors of the gastroduodenal area

Extrapancreatic cases of solid-pseudopapillary tumor (SPT) are exceedingly rare. We report here two cases of primary tumors located in the gastroduodenal region, morphologically identical to pancreatic SPT, but particular by their immunohistochemical features and malignant evolution. Clinical charts and all available histopathological material were reviewed; complementary immunohistochemical investigations and molecular analyses were performed. The patients were a 32-year-old female, submitted to surgical resection for a tumor of the prepyloric region, and a 73-year-old male presenting with a duodenal tumor and synchronous liver metastases. In the two cases, the primary tumor and all the metastases available for study were morphologically indistinguishable from typical pancreatic SPT. However, their immunohistochemical profile was characterized by the absence of hormone receptor expression and of nuclear localization of beta-catenin and E-cadherin. In the only case in which it was feasible, molecular analysis did not identify any mutation in the CTNNB1 gene. Both tumors had a malignant behavior, with extensive metastatic dissemination. In conclusion, we report two unusual cases of extrapancreatic SPT arising in the gastroduodenal area, associated with a malignant course and an extensive metastatic dissemination.

Solid Pseudopapillary Neoplasm of the Pancreas: A Rare and Atypically Aggressive Disease among Male Patients

Solid pseudopapillary neoplasm (SPN) of the pancreas is uncommon, has low metastatic potential, typically afflicts young females, and expresses progesterone receptors. In the rare male patient, its biologic behavior may be more aggressive and lethal. A retrospective case series analysis and literature review of SPN was performed to compare its clinical behaviors in males and females. The case series identified 11 patients of which only two were males. Ten patients underwent tumor resection with curative intent. The one operated male developed liver metastases 15 months postoperatively and subsequently died. The other male presented with advanced liver metastases and died 2 months later without operation. One female had regional lymph node metastases resected en bloc and all nine females are disease-free after a mean follow-up of 63.4 months. Analysis of 1014 patients reported in the literature revealed only 137 (13.5%) males. Males had a twofold higher incidence of metastases and a threefold higher death rate. In males, SPN has an atypically aggressive biology suggesting that progesterone and/or other sex hormones may have a role in oncoregulation.

Laparoscopic pancreatectomy for solid pseudo-papillary tumors of the pancreas is a suitable technique; our experience with long-term follow-up and review of the literature

BACKGROUND

Solid pseudopapillary tumors (SPTs) are rare pancreatic neoplasms of low malignant potential that occur mainly in young women. Only 17 cases of SPT treated laparoscopically have been published in the literature and long-term follow-up data are still lacking.

METHODS

Retrospective analysis of ten patients (8 women, 2 men; mean age, 25.4 years) (DS: 12.1; minimum 11, maximum 51) who underwent laparoscopic distal pancreatectomy with a definitive histological diagnosis of SPT. Long-term follow-up data were collected.

RESULTS

The average tumor size was 43.8 mm (minimum 20, maximum 65 mm). The mean operative time was 177.5 minutes (DS: 53.7; minimum 120, maximum 255). In all, five patients underwent distal splenopancreatectomy; five patients underwent spleen-preserving distal pancreatectomy of whom three with splenic vessel preservation and two with the Warshaw technique. The conversion rate was nil and no case of perioperative mortality was recorded. The mean hospital stay was 7 days (DS: 2.7; minimum 4, maximum 12). Six patients had an uneventful postoperative course and four had postoperative complications. Two of them underwent reoperation, and the other two had nonsurgical complications. After a median follow-up of 47 (range, 5-98) months, all patients were alive and disease-free.

CONCLUSIONS

Laparoscopic pancreatic resection is a safe and feasible procedure that could become the treatment of choice for patients affected by pancreatic SPT. Distal pancreatectomy should be performed, if possible, with spleen-preserving technique, especially in young patients. To avoid metastatic spread, laparoscopic or laparotomic biopsy should not be performed in patients affected by SPT.

Solid pseudopapillary tumor of the pancreas: A review of 553 cases in Chinese literature

AIM: To sum up the clinical and pathological characteristics of solid pseudopapillary tumor (SPT) and the experience with it.

METHODS: A total of 553 SPT patients reported in Chinese literature between January 1996 and January 2009 were retrospectively reviewed and analyzed.

RESULTS: The mean age of the 553 SPT patients included in this review was 27.2 years, and the male to female ratio was 1:8.37. Their symptoms were non-specific, and nearly one third of the patients were asymptomatic. Computed tomography and ultrasonography were performed to show the nature and location of SPT. Most of the tumors were distributed in the pancreatic head (39.8%), tail (24.1%), body and tail (19.5%). Forty-five patients (9.2%) were diagnosed as malignant SPT with metastasis or invasion. None of the clinical factors was closely related to the malignant potential of SPT. Surgery was the main therapeutic modality for SPT. Local resection, distal pancreatectomy and pancreatoduodenectomy were the most common surgical procedures. Local recurrence and hepatic metastasis were found in 11 and 2 patients, respectively, after radical resection. Four patients died of tumor progression within 4 years after palliative resection of SPT. The prognosis of SPT patients was good with a 5-year survival rate of 96.9%.

CONCLUSION: SPT of the pancreas is a rare indolent neoplasm that typically occurs in young females. It is a low-grade malignancy and can be cured with extended resection. The prognosis of such patients is good although the tumor may recur and metastasize.

Localized intrapancreatic malignant mesothelioma: a rare entity that may be confused with other pancreatic neoplasms

Malignant mesothelioma usually presents with diffuse involvement of the pleura or peritoneum. Circumscribed or localized malignant mesothelioma has been described in these locations, as well as the viscera, in which case it may cause diagnostic confusion with other, more common entities. Herein, we describe the first well-documented case of primary intrapancreatic malignant mesothelioma in the English literature. The patient was an otherwise healthy 39-year-old woman who presented with a symptomatic mass in the head of the pancreas that was completely resected via pancreaticoduodenectomy. The tumor was composed of cysts, papillae, and tubules lined by cells with abundant eosinophilic cytoplasm and immunohistochemically expressed CA-125, calretinin, and D2-40. Follow-up revealed no evidence of residual or recurrent disease 32 months after surgery. This report also describes the clinical and pathologic characteristics of an intrapancreatic mesothelioma and provides a review of the literature regarding entities that may be considered in the differential diagnosis of this tumor.

Solid-pseudopapillary neoplasm: a pancreatic enigma

Solid-pseudopapillary neoplasm of the pancreas is a relatively uncommon tumor. It typically affects young women, has nonspecific clinical and radiologic manifestations, and can be readily diagnosed by ultrasound-guided fine-needle aspiration and histopathologic evaluation. Histologic features characteristically show loosely cohesive, relatively uniform polygonal cells surrounding delicate capillary-sized blood vessels. Other features include cytoplasmic vacuolization, finely stippled chromatin, nuclear grooving, eosinophilic hyaline globules, and degenerative changes. Almost all solid-pseudopapillary neoplasms harbor mutations in the beta-catenin gene. They stain with beta-catenin, CD10, and focally with neuroendocrine markers. Although previously considered benign, this tumor is currently considered a low-grade malignant epithelial neoplasm with low metastatic rate and high overall survival. Most patients are cured by complete surgical excision. Despite the characterization of the morphologic and molecular features of this enigmatic neoplasm, more work is needed to uncover its cell of origin and true histogenesis.

Solid pseudopapillary neoplasms of the pancreas

SPN is a rare neoplasm that affects mainly young women. Despite this feature, SPN have been seen in both genders, multiple races, and at a wide range of ages. The genetic mechanism behind the development of SPN is distinct from the more lethal ductal carcinoma of the pancreas. This difference is reflected in the favorable outcome for patients with SPN. Surgery is typically curative in patents with localized disease and possibly in patients with limited metastasis or local extension. No consensus exists on an effective systemic therapy. There are no reliable predictors for disease-specific mortality or recurrence in the minority of patients who develop aggressive disease.

Is laparoscopic management suitable for solid pseudo-papillary tumors of the pancreas?

PURPOSE

Solid pseudo-papillary tumors (SPT) are rare pancreatic neoplasms of low-malignant potential occurring mainly in young women. The purpose of this report is to describe our experience with laparoscopic management of these tumors with 4-year follow-up.

METHODS

Three children with SPT were admitted to two hospitals in Paris, France, between February 2000 and December 2006. Diagnosis or treatment was carried out using laparoscopic techniques (biopsy and resection in one case and biopsy only in two). Long-term follow-up data were collected.

RESULTS

All three patients presented recurrences within 3 years after resection, i.e., disseminated peritoneal recurrence in two patients and local recurrence in one. The two patients with peritoneal recurrences were treated by surgical resection and chemotherapy. The patient with local recurrence could not be treated due to contraindicating local factors. All three patients were alive at the time of this writing.

CONCLUSION

This is the first report describing long-term follow-up after laparoscopic management of SPT. All three patients developed recurrences. These poor results contrast sharply with the low risk of local or disseminated recurrence after open laparotomy without chemotherapy that has been considered as the treatment of choice up to now. Recurrences after laparoscopic management may have been due to diffusion of tumor cells caused by gas insufflation especially during biopsy. Laparoscopic biopsy should not be performed in patients presenting SPT.

Expression of Wnt target genes in solid pseudopapillary tumor of the pancreas: a pilot study

OBJECTIVES

Solid pseudopapillary tumor (SPT) of the pancreas is very rare. This study was performed to analyze the expression of Wnt signal target genes (matrix metalloproteinase-7 [MMP-7], cyclin-D1, and c-myc) and Ki-67 in resected SPTs to determine their clinicopathologic characteristics according to their expression.

METHODS

From January 1995 to December 2005, 23 patients underwent pancreatic resections for SPT of the pancreas. Among 23 formalin-fixed, paraffin-embedded tissues, 12 were evaluated as a pilot study. Immunohistochemistry was performed using various detection and antigen retrieval methods to detect MMP-7, cyclin-D1, c-myc, and Ki-67. The expression of Wnt target genes was correlated with clinicopathologic features of the patients.

RESULTS

Solid pseudopapillary tumors of the pancreas always showed cytoplasmic/nuclear accumulation of [beta]-catenin, frequent expression of cyclin-D1, and low proliferation index. MMP-7, cyclin-D1, c-myc, and Ki-67 were not correlated with microscopic features suggesting malignant potential (P > 0.05). Tumor size was closely related to microscopic features of malignant potential and apparently has an inverse relationship with the expression of cyclin-D1 and Ki-67 (P < 0.05).

CONCLUSIONS

Low proliferative index and associated MMP-7 expression may cause an unpredictable clinical course in this tumor. Subtle changes in the intracellular environment, not pathologic (morphologic) changes, may elucidate the unpredictable clinical course of this tumor.

Update on the molecular pathogenesis of pancreatic tumors other than common ductal adenocarcinoma

PURPOSE

Although ductal adenocarcinoma is the most common and well known pancreatic tumor type, other distinct epithelial neoplasms affecting the pancreas that show different symptoms, biological behaviors and outcomes are becoming more frequently recognized and documented. Pancreatic epithelial tumors may be separated into ductal and nonductal neoplasms. The former group includes pancreatic ductal adenocarcinoma, intraductal papillary-mucinous tumor, mucinous cystic tumor and serous cystic tumor. The latter group includes pancreatic endocrine tumor, pancreatic acinar cell carcinoma, pancreatoblastoma and solid-pseudopapillary tumor. The aim of this review is to summarize recently acquired knowledge regarding the molecular characterization of these uncommon pancreatic epithelial neoplasms.

RECENT FINDINGS

Molecular studies of uncommon pancreatic epithelial tumors suggest that the different morphological entities are associated with distinct molecular profiles, highlighting the involvement of different molecular pathways leading to the development of each subtype of pancreatic neoplasm.

CONCLUSION

The correct classification of rare pancreatic epithelial tumors and the identification of their characteristic molecular aspects is the fundamental starting point in identifying novel diagnostic molecular tools and new targets for innovative therapeutic strategies.

Acinar cell carcinoma versus solid pseudopapillary tumor of the pancreas in children: a comparison of two rare and overlapping entities with review of the literature

Primary epithelial tumors of the pancreas are extremely uncommon in children, and among these, acinar cell carcinoma (ACC) is the most rare. Here we describe our recent observations in the case of a 10-year-old boy with one of these exceptional examples. The histologic diagnosis of ACC was supported by both immunohistochemistry and electron microscopy. Despite its rarity, ACC should be kept in the differential diagnosis of pediatric pancreatic exocrine tumors. We also provide a comparison with an example of solid pseudopapillary tumor, another relatively infrequent epithelial tumor of the pancreas in the young. We review the relevant literature addressing the clinical and pathologic features of ACC and its distinction from other pancreatic neoplasms.

Current diagnosis and management of unusual pancreatic tumors

BACKGROUND

The finding of a solid or cystic mass in the pancreas is becoming more common secondary to the increasing use of cross-sectional imaging and the improved sensitivity of such studies for the detection of pancreatic abnormalities. Because of the aggressive natural history of pancreatic cancer, this has caused concern that all pancreatic abnormalities may be cancer as well as confusion over proper diagnostic and treatment algorithms. This review provides an overview of the natural history, diagnostic considerations, and treatment recommendations for the less common tumors of the pancreas which can be misinterpreted as pancreatic cancer including: solid pseudopapillary tumors (SPT), acinar cell carcinoma (ACC), lymphoplasmacytic sclerosing pancreatitis (LPSP), primary pancreatic lymphoma (PPL), and metastatic renal cell carcinoma to the pancreas.

DATA SOURCES

A Medline search was conducted to identify studies investigating the clinicopathologic features, molecular genetics, pathogenesis, diagnosis, and treatment of SPT, ACC, LPSP, PPL, and pancreatic metastases.

CONCLUSIONS

It is often possible to obtain an accurate pretreatment diagnosis for these unusual pancreatic tumors and to successfully differentiate them from the more common pancreatic malignancies.

Solid-pseudopapillary tumor of the pancreas showing a remarkable reduction in size over the 10-year follow-up period

An 18-year-old healthy woman was admitted to our department for further evaluation of a pancreatic mass (45 mm in diameter) by transabdominal ultrasound at a general health check. Solid-pseudopapillary tumor (SPT) was suspected from the findings of diagnostic images. Therefore, surgery was recommended. The patient and her family, however, refused surgery. Ultrasound-guided transcutaneous biopsy revealed proliferation of tumor cells with small nuclei showing a pseudopapillary arrangement. PAS positive granules and alpha-1-antitrypsin positive cells were proven, which led to the diagnosis of SPT. As the grade of atypism of the tumor cells was low, the patient underwent follow-up examination once a year at our outpatient department thereafter. The tumor gradually decreased its maximum diameter in 10 years from 45 mm to 15 mm. Thus far, there have been very few reports on the natural course of SPT, and this is the first report describing marked spontaneous shrinkage of a tumor in a long follow-up period.

Solid pseudopapillary tumor of the pancreas: a review of salient clinical and pathologic features

Solid pseudopapillary tumor (SPT) of the pancreas is a rare tumor of uncertain histogenesis characterized, as the name suggests, by a cystic and solid pattern of growth with formation of pseudopapillae. Accounting for only a small percentage of pancreatic neoplasms, SPT occurs primarily in young women, although cases in older patients and men have been reported. The tumor is thought to have low-grade malignant potential, as the majority of the cases are cured by simple but complete surgical resection. Knowledge of the unique morphologic and demographic characteristics of this neoplasm is essential for accurate diagnosis. Herein, we review the clinical and pathologic features, which can help separate SPTs from other primary pancreatic tumors.

Solid pseudopapillary neoplasm of the pancreas: distinct patterns of onset, diagnosis, and prognosis for male versus female patients

BACKGROUND

Solid pseudopapillary neoplasm of the pancreas is a distinctive pancreatic neoplasm with low metastatic potential. This study examines clinical differences and prognosis between male and female patients.

METHODS

The medical records of 34 consecutive patients with pancreatic solid pseudopapillary neoplasms between 1990 and 2006 were reviewed. Whenever feasible, organ-preserving operation was performed. Statistical analysis was performed using chi-square and Student t test.

RESULTS

There were 27 women (79%) and seven men (21%) with median age of 23 years. Mean diameter of the tumor was 7 cm. Tumor size tended to be smaller in patients treated in more recent years. Conservative surgery was possible in 11 patients including spleen-preserving distal pancreatectomy in 3, central pancreatectomy in 5, and enucleation in 3 patients. Median hospital stay was 11 days, morbidity rate was 62%, including 17 patients with grade A pancreatic fistula, and there was no operative mortality. Mean follow-up time was 84 months. Tumor recurred in 2 patients (6%). Overall late morbidity rate was 12%. At the time of diagnosis, age was (x +/- SD) higher among male patients (25 +/- 2 years vs 37 +/- 7 years; P <.05) with no difference in tumor size. The neoplasms were more aggressive in male patients; therefore, conservative surgery was less likely. There was no correlation between tumor aggressiveness and age of the patient or size of tumor.

CONCLUSION

This is the first single center study to demonstrate that solid pseudopapillary neoplasms in male patients have distinct patterns of onset and aggressiveness when compared with female patients. Although valid prognostic criteria are still lacking, it appears that male patients may be best treated by more radical operation and should be observed more closely during follow-up.

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.