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

Molecular alterations in pancreatic tumors

Genetic alterations in pancreatic tumors can usually be classified in: (1) Mutational activation of oncogenes; (2) Inactivation of tumor suppressor genes; and (3) Inactivation of genome maintenance genes controlling the repair of DNA damage. Endoscopic ultrasound-guided fine-needle aspiration has improved pre-operative diagnosis, but the management of patients with a pancreatic lesion is still challenging. Molecular testing could help mainly in solving these “inconclusive” specimens. The introduction of multi-gene analysis approaches, such as next-generation sequencing, has provided a lot of useful information on the molecular characterization of pancreatic tumors. Different types of pancreatic tumors (e.g., pancreatic ductal adenocarcinomas, intraductal papillary mucinous neoplasms, solid pseudopapillary tumors) are characterized by specific molecular alterations. The aim of this review is to summarize the main molecular alterations found in pancreatic tumors.

Solid-pseudopapillary Neoplasms of the Pancreas is still an Enigma: a Clinicopathological Review

The solid-pseudopapillary neoplasm of the pancreas is a rare but enigmatic entity occurring mainly in young women. Since the first description by V. Frantz in 1959 the terminology of this tumor has continuously changed but it has remained simply descriptive, because the exact histogenesis is still obscure. Although in majority of cases the survival is excellent, nevertheless, the expected prognosis is not exactly predictable. In this review the authors aim to summarize its clinico-pathological features, the expected biological behavior, the molecular alterations, the immune phenotype and discuss the putative histogenesis. From diagnostic point of view, the salient histological characteristic findings are analyzed that would help to differentiate it from other, look-alike pancreatic tumors, and suggestions are made about the desirable content of the histological report.

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.

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.