Solid-Pseudopapillary Neoplasm of the Pancreas: Cytomorphologic Findings and Literature Review

Abstract

Background: Solid-pseudopapillary neoplasm (SPN) is a rare pancreatic malignancy with an excellent prognosis. It is most commonly diagnosed in young women. This article comprehensively reviews the clinical, pathological and radiological features of this neoplasm, as well as its clinical management. Methods: A literature review of SPN was performed of all articles published in the English language in PubMed prior to November 1, 2013. Cytomorphological features, histopathology, immunohistochemistry, patient general demographics, molecular studies, radiologic imaging and clinical management were reviewed. Results: SPN displays distinct cytomorphological features on fine-needle aspiration - thin, delicate, branching vessels in a ‘Chinese character' pattern lined by one to several layers of loosely cohesive neoplastic cells. Nuclear features include indented or grooved nuclei with an evenly distributed chromatin pattern and small inconspicuous nucleoli. SPN is characteristically immunoreactive for CD10, β-catenin (in an abnormal nuclear pattern), CD99 in a perinuclear dot-like pattern, α1-antitrypsin, and progesterone receptor. Almost all SPNs harbor an activating point mutation in exon 3 of the β-catenin gene (CTNNB1). Clinicopathological features generally do not correlate with prognosis, and most patients experience excellent long-term survival. Conclusions: SPN can mimic other neoplasms of the pancreas, which can lead to diagnostic challenges in a limited cytologic specimen. Distinct cytomorphological features can help distinguish SPNs from other pancreatic neoplasms. Complete surgical resection as well as resection of metastatic disease is preferred given a low rate of tumor recurrence and long periods of disease-free intervals.

Pancreatic surgery for tumors in children and adolescents

“…Although there is no conclusive evidence, a few case reports suggest a possible association between SPN and familiar adenomatous polyposis (FAP). The association with FAP is supported by anecdotal observations of shared mutations in the Wnt signaling pathway in the germline of patients with FAP and somatically in SPN [18].…”

The Dilemma of “Indeterminate” Interpretations of Pancreatic Neuroendocrine Tumors on Fine Needle Aspiration

“…[10][11][12] Contamination from other sites has also been described to cause diagnostic difficulty in some cases. 15 However, SPN 16,17 can appear morphologically similar in limited biopsy and may also express synaptophysin and CD56 which is why several immunostains-including CD10, beta-catenin and CD99 in a peri-nuclear dot pattern-are often part of the ICC panel. 15 However, SPN 16,17 can appear morphologically similar in limited biopsy and may also express synaptophysin and CD56 which is why several immunostains-including CD10, beta-catenin and CD99 in a peri-nuclear dot pattern-are often part of the ICC panel.…”

“…17 Thus, ICC is more commonly used to rule out PanNET than to rule out SPN. Definitively ruling out SPN appears to be less of a concern in these cases given that only 1 case underwent beta-catenin staining.…”

Traumatic rupture of solid pseudopapillary tumors of the pancreas in children: A case report

“…Solid pseudopapillary tumors (SPTs) of the pancreas are a rare occurrence, accounting for 1-2% of all solid pancreatic tumors (1). SPT is more prevalent in females and is more frequently encountered in adolescence.…”