[459] Solid Pseudopapillary Tumor of the Pancreas: Spectrum of Clinical Presentations and Morphologic Variants

Po Zhao, Pedro deBrito, Mary K Sidawy. Georgetown University Hospital, Washington, DC

Background: Solid pseudopapillary tumor (SPT) of the pancreas is a rare neoplasm predominantly seen in young women. It typically presents as a large tumor with cystic and solid components. The major differential diagnosis includes pancreatic endocrine tumor (PEN). This study presents our experience with this tumor with emphasis on two morphologic variants: SPT with signet ring cells, and SPT with clear cells.
Design: Fifteen histologically confirmed SPT were identified in our files. Endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) was performed in 8/15 cases. Patients' demographics, cytohistologic correlation and tumor characteristics were evaluated.
Results: The results are summarized in the table.

Age (yr)SexSiteSize (cm)FNA DxGross
23FBody/tail1.7NondiagnosticSolid
36FBody/tail2.3SPT vs. PENSolid
27MBody/tail3.6Malignant with signet ring featuresSolid
36FBody/tail3.5SPTSolid
55FBody/tail3.5SPT vs. PENCystic
50FBody/tail8.5SPTSolid & cystic
39FHead1.5SPTSolid
25FBody/tail2SPT with vacuolated cellsSolid & cystic
17FHead3NDSolid
45MBody/tailNANDSolid
23FHead6.5NDSolid
24FBody/tail8.5NDCystic
42FBody/tailNANDNA
73MBody/tail3.2NDSolid
38MBody/tail2.7NDSolid
ND - not done; NA - not available

11/15 subjects were female and 4 were male with an age range of 17-73 years. 12 SPT were located in the pancreatic body/tail, and 3 in the head. Tumor size ranged from 1.5-8.5 cm and 10 were solid. Of the 8 EUS-FNA, 4 were diagnosed as SPT, 2 as SPT vs. PEN, 1 as malignant with signet ring features, and 1 was nondiagnostic. Immunohistochemistry (IHC) was performed on cell blocks in 6/8 FNAs. Panels included β-catenin, CD10, vimentin, CD56, synaptophysin, chromogranin and keratin. The 2 variants are illustrated: SPT with signet cells (A,B,C), SPT with clear cells (D,E,F).


Conclusions: SPT may occur in males and older adults, and present as a small or solid tumor. Variants with signet cells or clear cytoplasm may pose a diagnostic challenge. However, when combined with the appropriate IHC studies, an accurate diagnosis can be provided by FNA and histologically. Awareness of the wide spectrum of its clinical presentations and morphologic variants can prevent diagnostic pitfalls.
Category: Cytopathology

Monday, March 19, 2012 9:30 AM

Poster Session I Stowell-Orbison/Surgical Pathology/Autopsy Awards Poster Session # 56, Monday Morning

 

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