Cytologic features Clean background Clusters and single cells

Cytologic features • Clean background • Clusters and single cells • Uniform, round to oval nuclei and nuclear groove • Inconspicuous nucleoli • Even chromatin pattern • Scant to moderate cytoplasm

Differential diagnosis • • • Solid pseudopapillary tumor Pancreatic endocrine neoplasm Acinar cell carcinoma Pancreatoblastoma Ductal adenocarcinoma Mass forming pancreatitis

SPT Age and sex Smear background Smear pattern Nuclei 20~30 years old Female >>> Male Clean or filled with hemorrhagic debris Highly cellular with papillary fragments, loose clusters and single cells Uniform, oval with nuclear grooves and indentations Nuclear chromatin Nucleoli Mitoses Even and finely PEN 40~60 years old Male = Female Generally clean Dishesive, single cell pattern; few small cluster Clean or granular form stripped cytoplasm Solid sheets and groups, loss of organoid grape-like clustering 2~3 years old >> 40 years old Male = Female 60~70 years old Male >> Female Generally clean Clean and mucinous Cellular with cluster and single cell; recognizing squamoid corpuscles 40~60 years old Male >> Female Fat necrosis, histiocytosis, inflammation Few scattered ductal group +/admixed acinar cells This case 41/Male Clean Clusters and single cells Coarse variable Parachromatin clearing Generally smooth and even Usually prominent but may be absent Usually prominent Variable but usually none or rare None to rare Variable Rare to few None or rare and normal No Dense to finely granular, rarely clear or oncocytic Relatively abundant and granular Generally granular Visible and generally abundant, variably vaculoated and mucinous Visible and nonmucinous in general Scant and eccentrically placed in the cell None or small but can be prominent Round and uniform with mild anisonucleosis Scant to Cytoplasm Ductal group only CP Round to oval and relatively uniform; smooth Absent to moderate with occasional perinuclear vacuole or hyaline globule WDAC Enlarged with anisonucleosis of 1: 4 in a group; variable nuclear membrane abnormality coarse, stippled, ‘salt-n-pepper’ Absent Adults in 60’s Male : Female = 4: 1 PBL Tri-lineage epithelial differentiation with most cells demonstrating acinar feature Round to oval granular inconspicuous ACC nuclear membrances None or small and variably prominent Round to oval nuclei, and nuclear groove Even chromatin Inconspicuous Abbreviation: SPT, solid pseudopapillary tumor; PEN, pancreatic endocrine neoplasm; ACC, acinar cell carcinoma; PBL, pancreatoblastoma; WDAC, adenocarcinoma, well differentiated; CP, chronic pancreatitis

DIAGNOSIS: Pancreas, body, endoscopic ultrasoundguided fine-needle aspiration cytology: Solid pseudopapillary tumor.