Detection of t(11;22)(q24;q12) translocation and EWS-FLI-1 fusion transcript in a case of solid pseudopapillary tumor of the pancreas

Solid pseudopapillary tumor of the pancreas: A systematic review of clinical, surgical and oncological characteristics of 1384 patients underwent pancreatic surgery

BACKGROUND

Pancreatic solid pseudopapillary tumors (SPTs) are rare clinical entity, with low malignancy and still unclear pathogenesis. They account for less than 2% of exocrine pancreatic neoplasms. This study aimed to perform a systematic review of the main clinical, surgical and oncological characteristics of pancreatic SPTs.

DATA SOURCES

MEDLINE/PubMed, Web of Science and Scopus databases were systematically searched for the main clinical, surgical and oncological characteristics of pancreatic SPTs up to April 2021, in accordance with the preferred reporting items for systematic reviews and meta-analyses (PRISMA) standards. Primary endpoints were to analyze treatments and oncological outcomes.

RESULTS

A total of 823 studies were recorded, 86 studies underwent full-text reviews and 28 met inclusion criteria. Overall, 1384 patients underwent pancreatic surgery. Mean age was 30 years and 1181 patients (85.3%) were female. The most common clinical presentation was non-specific abdominal pain (52.6% of cases). Mean overall survival was 98.1%. Mean recurrence rate was 2.8%. Mean follow-up was 4.2 years.

CONCLUSIONS

Pancreatic SPTs are rare, and predominantly affect young women with unclear pathogenesis. Radical resection is the gold standard of treatment achieving good oncological impact and a favorable prognosis in a yearly life-long follow-up.

Solid Pseudopapillary Neoplasm of Pancreas; A Case Series and Review Literature

BACKGROUND

Information regarding solid pseudopapillary neoplasm (SPN) of the pancreas is limited in Iran. We aimed to review the clinicocytopathological features and follow-up of patients with SPN of pancreas who were diagnosed in a single center in Iran.

METHODS

Seven patients with SPN of the pancreas were diagnosed during January 2010 to March 2015 at the Digestive Disease Research Institute of Tehran University of Medical Sciences. The patients were reviewed prospectively.

RESULTS

Six out of the 7 patients were female and the mean age of all the patients was 29.4 years ranging from 15 to 61 years. The most common clinical presentation was nonspecific abdominal pain (N=6). The tumors were located mostly in head and neck of the pancreas. SPN was diagnosed in all patients by fine needle aspiration through endosonography (EUS-FNA). All patients underwent surgery. Histological findings of surgical tissues were consistent with EUS-FNA. The postoperative follow-up period of about 14 months was uneventful.

CONCLUSION

SPN of the pancreas is a rare pancreatic tumor which affects primarily young women. EUS-guided FNA could play an important role in preoperative diagnosis of SPN of the pancreas.

Array comparative genomic hybridization analysis of solid pseudopapillary neoplasms of the pancreas

Solid pseudopapillary neoplasms of the pancreas are low-grade malignancies, but their biological behavior cannot be stratified solely on the basis of histopathologic criteria. Aside from mutations in beta-catenin and lack of genetic changes common to pancreatic ductal adenocarcinomas, little is known about the chromosomal alterations in solid pseudopapillary neoplasms. We applied array comparative genomic hybridization to a series of 12 patients. The average age was 31 years (range 12-52 years) with 10 female and 2 male patients. The average tumor size was 7.3 cm (range 2-24 cm) with five lesions greater than 5 cm. All cases had 'bland' cytology without significant pleomorphism or high nuclear grade, but seven cases demonstrated at least one of these potentially aggressive histopathologic features: size >5 cm, tumor necrosis, lymphovascular invasion, perineural invasion and peripancreatic invasion. Clinically, one lesion demonstrated aggressive behavior. By array comparative genomic hybridization, chromosomal losses and/or gains were identified in eight cases; five cases had multiple (five or more) alterations. The most common alterations were gains at 13q, 17q, 1q and 8q. Six of the seven cases with at least one aggressive feature had genetic alterations, while only two cases without adverse features had genetic alterations (P=0.024). The single clinically aggressive tumor exhibited seven chromosomal gains and four aggressive histopathologic features. Our study demonstrates that genetic alterations detected by array comparative genomic hybridization are common in solid pseudopapillary neoplasms of the pancreas. Additional study and longer follow-up are needed to determine if these genetic abnormalities could help predict clinical behavior in these neoplasms.

Leydig cell tumor after treatment for Ewing's sarcoma

Leydig cell tumors account for 3% of testicular tumors and have never been reported after treatment for Ewing's sarcoma. We report the unusual occurrence of a patient who developed a Leydig cell tumor of the testis 18 years after successful treatment for Ewing's sarcoma. Additional monitoring for second malignancies may become appropriate as long-term survival continues to improve for patients with Ewing's sarcoma.

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.

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.

Solid pseudopapillary neoplasms of the pancreas are associated with FLI-1 expression, but not with EWS/FLI-1 translocation

Solid pseudopapillary neoplasms of the pancreas are rare pancreatic tumors with mostly benign behavior, affecting almost exclusively women. Their histogenetic origin is still unsolved, but a recently reported EWS/FLI-1 translocation t(11;22)(q24;q21) and the consistent expression of CD56 and the progesterone receptor, both genes located on the long arm of chromosome 11, point to chromosome 11q as a potential locus of gene aberration in solid pseudopapillary neoplasms. To further elucidate this issue, we studied 30 cases of solid pseudopapillary neoplasms by comparative genomic hybridization (CGH), fluorescent in situ hybridization (FISH) and immunohistochemistry. Immunohistochemically, 38% showed nuclear expression of FLI-1 and all cases revealed positivity for CD56 and the progesterone receptor, whereas no solid pseudopapillary neoplasm expressed CD34. No translocation of the EWS gene was found by FISH and no gross chromosomal gain or loss was detected by CGH. It is concluded that FLI-1 expression in solid pseudopapillary neoplasms is not associated with an EWS/FLI-1 translocation. In addition, there are no chromosomal gains or losses, especially on chromosome 11, where the FLI-1 gene is located adjacent to the gene for CD56 (NCAM). These data add another feature to the complex phenotypic appearance of solid pseudopapillary neoplasms.

The Clear Cell Variant of Solid Pseudopapillary Tumor of the Pancreas: A Previously Unrecognized Pancreatic Neoplasm

Solid pseudopapillary tumor is a rare but distinctive pancreatic neoplasm whose cell phenotype remains a mystery. We report 3 cases of a previously undescribed variant of solid pseudopapillary tumor of the pancreas composed almost entirely of multivacuolated clear cells (>90%). The cytoplasmic vacuoles did not contain glycogen, mucin, or lipid but seemed to be formed by dilatation of the endoplasmic reticulum and mitochondria. The tumors displayed prominent trabeculae and a solid growth pattern but lacked the characteristic pseudopapillary pattern of the classical solid pseudopapillary tumor. In contrast, the clinical features, gross characteristics, and immunoprofile were similar to those of classical solid pseudopapillary tumor. Two of the patients were young adult females with well-demarcated tumors involving the body and tail of the pancreas. Tumor cells showed immunoreactivity for vimentin, CD10, CD56, synaptophysin, and nuclear accumulation of beta catenin. In 2 patients, 1 male and 1 female, the tumors were discovered incidentally. Despite vascular invasion in one of the tumors all 3 patients are disease free after distal pancreatectomy. Clues to distinguish the clear cell variant of solid pseudopapillary tumor from endocrine pancreatic tumor composed of clear cells, clear and foamy cell variants of ductal carcinoma, metastatic renal cell carcinoma, serous cystadenoma and ectopic adrenocortical nodules are provided.

Previously unidentified complex cytogenetic changes found in a pediatric case of solid-pseudopapillary neoplasm of the pancreas

Solid pseudopapillary neoplasm of the pancreas (SPNP) is a rare tumor with low malignant potential found in adolescent girls and young women. The pathogenesis of SPNP remains uncertain and its management is controversial. Genetic changes associated with SPNP have seldom been reported. We describe here the cytogenetic investigation of a case of SPNP in a 13-year-old girl whose tumor cells revealed two unrelated clones: one clone characterized by complex karyotypic changes, including breakpoints in two common fragile sites at chromosome 2, band q33, and chromosome 4, band q31, and the second clone defined by partial monosomy for chromosome X. Loss of heterozygosity for HRAS was also identified by array comparative genomic hybridization (a-CGH). These cumulative changes seem insufficient for activation of cell transformation, but could possibly play a role in priming the cell for future mutagenic events.

Ewing's sarcoma: diagnostic, prognostic, and therapeutic implications of molecular abnormalities

The identification of the non-random chromosome rearrangements between the EWS gene on chromosome 22q12 and members of the ETS gene family in Ewing's sarcoma, peripheral primitive neuroectodermal tumour, Askin tumour, and neuroepithelioma has been a key advance in understanding their common histogenesis and defining the Ewing's sarcoma family of tumours (ESFT). In addition to improvements in diagnosis and potentially the stratification of patients for risk, biological investigations of these gene fusions may define targets for much needed therapeutic strategies to eliminate minimal residual disease or metastatic disease. Insight into their relation with other oncogenic events in ESFT will advance risk group analysis and ultimately may improve clinical management and survival for patients with this disease.

Solid-pseudopapillary tumor of the pancreas: a neoplasm with distinct and highly characteristic cytological features

The solid-pseudopapillary tumor of the pancreas (SPTP) is an unusual low-grade malignant epithelial tumor affecting predominantly adolescent girls and young women. Although approximately 500 cases of SPTP have been described in the last 40 yr, its pathogenesis remains uncertain. However, the clinical features of this neoplasm are very characteristic and SPTP must be suspected in any young woman with a cystic or partially cystic pancreatic mass. In this report, we describe the cytologic features of seven cases of SPTP investigated by preoperative fine-needle aspirates. The analysis of the cytologic features in these cases and in 43 cases collected from the literature reveals that they are highly characteristic and quite distinct from those of other cystic or solid tumors of the pancreas. On this basis, a cytologic diagnosis of SPTP may be rendered with great confidence, not only in clinically typical examples, but also in unusual presentations, such as in older patients, in males, in ectopic locations, and in metastatic sites.

Solid-pseudopapillary tumors of the pancreas are genetically distinct from pancreatic ductal adenocarcinomas and almost always harbor beta-catenin mutations

Solid-pseudopapillary tumors (SPTs) are unusual pancreatic neoplasms of low malignant potential that most frequently affect young women. Genetic events contributing to the development of SPTs are unknown. Whereas the more common ductal adenocarcinomas of the pancreas essentially never harbor beta-catenin or APC gene mutations, we have recently identified alterations of the APC/beta-catenin pathway in other nonductal pancreatic neoplasms including pancreatoblastomas and acinar cell carcinomas. We analyzed a series of 20 SPTs for somatic alterations of the APC/beta-catenin pathway using immunohistochemistry for beta-catenin protein accumulation, direct DNA sequencing of beta-catenin exon 3, and direct DNA sequencing of the mutation cluster region in exon 15 of the APC gene in those SPTs that did not harbor beta-catenin mutations. Immunohistochemical labeling for cyclin D1 was performed to evaluate the overexpression of this cell-cycle protein as one of the putative downstream effectors of beta-catenin dysregulation. In addition, we analyzed the SPTs for genetic alterations commonly found in pancreatic ductal adenocarcinomas, including mutations in the K-ras oncogene and p53 and DPC4 tumor suppressor genes, using direct DNA sequencing of K-ras and immunostaining for p53 and Dpc4. Almost all SPTs harbored alterations in the APC/beta-catenin pathway. Nuclear accumulation of beta-catenin protein was present in 95% (19 of 20), and activating beta-catenin oncogene mutations were identified in 90% (18 of 20) of the SPTs. Seventy-four percent (14 of 19) showed overexpression of cyclin D1, ranging from 10 to 70% of tumor nuclei. In contrast, no K-ras mutations were present in any of the 20 SPTs, and Dpc4 expression was intact in all 16 SPTs for which immunohistochemical labeling was successful. Overexpression of p53 was limited to only 3 of 19 (15.8%) SPTs. These results emphasize the two distinct, divergent genetic pathways of neoplastic progression in pancreatic ductal and nonductal neoplasms.