S66 Abstracts

a neuroendocrine neoplasm, a known pitfall in this diagnosis. The impact ofthese errors is minimal.

152

Fine Needle Aspiration of Oncocytic Variant of Pancreatic EndocrineNeoplasm: 3 Cases Misdiagnosed

Shaoxiong Chen, MD, PhD, Jingmei Lin, MD, PhD, Xiaoyan Wang, MDIndiana University, Indianapolis, Indiana

Introduction: Oncocytic variants of pancreatic endocrine neoplasm (PEN)are rarely seen in our daily practice and their cytomorphological features arerarely reported. Here we report a study of 3 cases of oncocytic variants ofPENs identified over an 18-year period. All these cases were misdiagnosedby FNA as adenocarcinoma (2) and suspicious for carcinoma (1). In thisstudy, cytomorpholoigcal features of oncocytic variants of PENs anddifferential diagnoses will be discussed.Materials and Methods: A computerized search of our laboratory informationsystem was performed for the 18-year period from July 1992 through June2010. Three cases of misdiagnosed oncocytic variant of PEN were identified.Results: Cytomorphological features of oncocytic variants of PEN consistof cohesive clusters of large cells with abundant eosinophilic granularcytoplasm, anisonucleosis, prominent nucleoli, and relative smooth nuclearmembrane. Nuclei are round to oval with finely granular chromatin.Additional features include rare isolated cells and glandular formation. Incontrast to typical PENs, cells are larger and more cohesive. Single cells,plasmacytoid cells and naked nuclei are rare. H&E sections from cell blockmaterial shows cords of atypical cells with similar morphological changeand finely granular chromatin. Histological examination shows sheets oflarge tumor cells with round or oval nuclei, smooth nuclear membrane,granular chromatin, anisonucleosis, and abundant granular cytoplasm. Insome areas, trabecular and glandular patterns are also present. Histologicalfeatures were diagnostic of oncocytic variants of pancreatic neuroendocrinetumor. However, these cases were misdiagnosed by FNA as adenocarci-noma (2) and suspicious for adenocarcinoma (1).Conclusions: Both oncocytic variant of PENs and pancreatic ductaladenocarcinoma (PDA) can have overlapping morphological features.Reliance on cytomorphological features only is fraught with diagnosticpitfalls. Additional differential diagnoses include acinar cell carcinoma(ACC), metastatic renal cell carcinoma (RCC) and metastatic hepatocellularcarcinoma (HCC).

153

Metastatic Tumors to the Pancreas e A Cytodiagnostic Challenge andthe Importance of Clinicopathologic Correlation

Nagarjun Rao, MD, FRCPath, Jessica Lelinski, MD, Bryan C. Hunt, MDMedical College of Wisconsin, Milwaukee, Wisconsin

Introduction: The pancreas is an uncommon site for metastasis of tumorsfrom other organs. Secondary pancreatic tumors, sampled by endoscopicultrasound-guided fine needle aspiration (EUS-FNA), are a diagnosticchallenge due to their rarity and lack of consistent defining clinical,radiologic, and cytomorphologic features.Materials and Methods: Following Institutional Review Board (IRB)approval, the electronic pathology database was searched for pancreaticEUS-FNA specimens from 2000-2012. Of 887 specimens identified, therewere 455 (51.3%) diagnoses of malignancy, including 18 (2.0% of allpancreatic FNAs, 3.9% of malignant cases) tumors metastatic to thepancreas. Clinical information was obtained from patients’ medical records.Cytology material, immunocytochemical stains and available surgicalpathology slides from the primary tumors were reviewed.Results: Primary tumor sites were widely distributed in the 18 casescomprising the study, including the appendix, bladder, esophagus, eye,lung, ovary, parotid, skin, and soft tissue. Histologic tumor types included10 carcinomas (56%), 4 sarcomas (22%), 2 lymphomas (11%), and 2melanomas (11%). Cytologic features alone strongly suggested a non-pancreatic origin for primary tumors including sarcoma, melanoma and

lymphoma. Ancillary studies used to support the diagnosis of metastasisincluded immunocytochemistry (50%) and flow cytometry (6%). Compar-ison with previous specimens was achieved in 61% cases. 67% hada positive cancer history known to the pathologist at the time of FNA, withan average interval between primary tumor and pancreatic metastasisdiagnosis of 4 years (range 0-12 years).Conclusions: This study confirms a wider array of primary tumor sites forpancreatic metastases than previously reported. A high index of suspicion isnecessary for the pathologist to arrive at the correct diagnosis from EUS-FNAspecimens. An approach combining clinical information, cytologic features,ancillary studies, and review of previous specimens provides the highestsensitivity and specificity in diagnosing these rare tumors of the pancreas.

154

Efficacy of Platinum Chemotherapy Agents in the Adjuvant Setting forAdenosquamous Carcinoma of the Pancreas

Avani S. Dholakia, BS1, Aaron T. Wild, BA1, Katherine Fan, BS1,Daniel A. Laheru, MD1, Luis A. Diaz, MD1, Lei Zheng, MD, PhD1,Dung T. Le, MD1, Ana De Jesus-Acosta, MD1, Susannah Ellsworth, MD1,Amy Hacker-Prietz, MS, PAC1, Matthew J. Weiss, MD1,Ralph Hruban, MD1, Khinh Ranh R. Voong, MD2,Phuoc T. Tran, MD, PhD1, John L. Cameron, MD1,Timothy Pawlik, MD, PhD, MPH1, Christopher L. Wolfgang, MD, PhD1,Joseph Herman, MD1

1Johns Hopkins University, Baltimore, Maryland; 2MD Anderson CancerCenter, Houston, Texas

Introduction: Pancreatic adenosquamous carcinoma (PASC) is a raresubtype of pancreatic adenocarcinoma. PASC accounts for only 1-4% ofexocrine pancreatic cancers and carries a particularly poor prognosis. Dueto the rarity of PASC, studies of therapies specifically targeting this subtypeare exceedingly limited. Based on efficacy of platinum agents againstsquamous carcinoma of other body sites, addition of these agents toadjuvant regimens may benefit patients with PASC.Materials and Methods: Records of all patients who underwent pancreaticresection at our institution from 1986-2012 were reviewed to identify thosewith PASC. Demographic, treatment, and survival data were collected. Patientswere divided into non-platinum (NPG) and platinum (PG) groups based onwhether or not they received a platinum agent as part of adjuvant therapy.Results: In total, 62 patients with PASC were identified among 5,627 cases(1.1%). Fourteen patients received a platinum agent in the adjuvant setting(PG), while 48 did not (NPG). These two groups were comparable withregard to median age (65 vs. 69 yrs, pZ0.34), gender (36 vs. 46% female,pZ0.50), performance status (78 vs. 79% ECOG 0, pZ0.98), histologicgrade (86 vs. 77% grade 3, pZ0.49), positive resection margins (14 vs.29%, pZ0.26), lymph node involvement (71 vs. 79%, pZ0.54), mediantumor diameter (4.0 vs. 4.3 cm, pZ0.64), and proportion receivingradiotherapy (57 vs. 42%, pZ0.31). PG patients received a median of5.5 cycles (IQR, 3.3-6.0) of platinum chemotherapy, with 10 patients (71%)receiving cisplatin-based regimens and 4 (29%) receiving oxaliplatin-basedregimens. PG patients experienced significantly longer median survival(19.1 months, 95% CI 12.8-25.4) compared to NPG patients (9.8 months,95% CI 7.3-12.4) (pZ0.024).Conclusions: Addition of a platinum agent to adjuvant regimens forresected PASC may improve survival among these high risk patients,though collaborative prospective investigation is needed.

155

Intranuclear Cytoplasmic Inclusions are a Specific Diagnostic FeatureDistinguishing Low-grade Pancreatic Intraductal Papillary MucinousNeoplasms from Contaminating Gastric Epithelium

Paul J. Lee, MD, PhD, Andrew H. Fischer, MD,Christopher L. Owens, MD, Lloyd Hutchinson, PhDUniversity of Massachusetts Medical School, Worcester, Massachusetts

Introduction: Low-grade Intraductal papillary mucinous neoplasms (IPMN)are challenging to diagnosis because of an absence of reliable morphologic or