[381] Identification of an Effective Antibody Panel in the Diagnosis of Pancreatic Ductal Adenocarcinoma on Fine Needle Aspiration Biopsy Specimens

V Anandan, J Shi, H Liu, S Meschter, F Lin. Geisinger Medical Center, Danville, PA

Background: Fine needle aspiration biopsy (FNAB) of the pancreas is often the diagnostic procedure of choice to establish the diagnosis of pancreatic ductal adenocarcinoma (PDA). However, the interpretation of FNAB specimens can be challenging due to overlapping cytological features between reactive conditions and PDA. Our unpublished data demonstrated that maspin, KOC, S100P and pVHL were the best antibody panel selected from 26 antibodies reported in the literature and tested to differentiate PDA from benign/reactive pancreatic ducts on surgical specimens. In this study, we further explore the utility of these 4 markers in confirming a benign or a malignant diagnosis in FNAB specimens on cell block preparation.
Design: Immunohistochemical evaluation of maspin, S100P, KOC, and pVHL was performed in 67 cases of FNAB specimens of the pancreas on cell block sections. The 67 cases were divided into 3 groups: Group 1 - 44 cases of PDA; Group 2 - 13 cases with a suspicious or indeterminate diagnosis; and Group 3 - 10 benign cases. The staining intensity (weak or strong) and distribution (negative, 1+, 2+, 3+ or 4+) were recorded. Follow-up surgical or clinical data confirmed the malignant diagnosis for all cases in group 1. Surgical or clinical follow-up data were available in 9 cases in the suspicious group, and all 9 cases were malignant.
Results: A strong and diffuse staining (3+ or 4+) for maspin, S100P, and KOC in 33 (79%), 35 (80%) and 19 (48%) cases in Group 1 and 9 (70%), 7 (54%), and 5 (39%) cases in Group 2 was seen. The 3 pVHL-negative cases contained very low cellularity. Maspin and S100P positive cases in the benign group were gastric contaminants. The results are summarized in Table 1.

Table 1. Summary of Immunohistochemical Staining Results
GroupsMaspin +S100P +KOC +pVHL +
PDA42/42* (100%)44/44 (100%)37/40* (93%)0/42* (0%)
Suspicious13/13 (100%)13/13 (100%)10/13 (77%)0/13 (0%)
Benign1/10 (10%)2/10 (20%)1/10 (10%)7/10 (70%)
*2 cases in the maspin and pVHL groups and 4 in the KOC group did not contain tumor cells in the deeper sections.

Conclusions: Our data indicate that maspin, S100P, KOC and pVHL are an effective antibody panel to confirm a benign diagnosis or PDA on FNAB specimens, which in turn will reduce the number of cases in a suspicious/indeterminate category. Caution should be taken because gastric contaminants can be positive for maspin and S100P.
Category: Cytopathology

Tuesday, March 23, 2010 8:00 AM

Platform Session: Section F, Tuesday Morning


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