[1866] Lymphoplasmacytic Sclerosing Pancreatitis with Neutrophilic Infiltration: Comparison with Cases without Neutrophilic Infiltration

Kenji Notohara, Kaori Uchino, Yoji Wani, Masayoshi Fujisawa, Katsuyuki Miyabe, Takahiro Nakazawa, Shigeyuki Kawa. Kurashiki Central Hospital, Kurashiki, Japan; Himeji Red Cross Hospital, Himeji, Japan; Nagoya City University, Nagoya, Japan; Shinshu University, Matsumoto, Japan

Background: Lymphoplasmacytic sclerosing pancreatitis (LPSP) and idiopathic duct-centric pancreatitis (IDCP) are recognized as different clinicopathologic entities; however sporadic examples with mixed features have been reported. The significance of such cases has not yet been elucidated.
Design: 31 Resected specimens of LPSP were selected for the study. The diagnosis of LPSP was based on at least 3 out of the following features: dense lymphoplasmacytic infiltration with fibrosis, numerous (>10/high power field) IgG4-positive plasma cells, storiform fibrosis and obliterative phlebitis. All the available H&E stained slides were reviewed. Due to neutrophilic infiltration being mainly identified in the lobules as detailed below, the number of foci (x10 objective) that contained 10 or more neutrophils in the lobules was counted in one slide. In 12 cases with multiple H&E slides, a slide with the most numerous neutrophilic infiltration was evaluated. Presence or absence of granulocytic epithelial lesion (GEL), which was defined as neutrophilic infiltration within the epithelia and/or lumens, in interlobular or intralobular ducts was also recorded.
Results: Lobular neutrophilic infiltration (LNI) was identified in 11 patients, among whom more than 5 such foci were identified in 6. Compared to cases with only one slide available, LNI was more common in cases with multiple slides (4/19 vs. 7/12; p<0.05), with the latter cases comprising of 5 out of 6 cases with more than 5 foci of LNI. LNI was more common at the periphery of the typical LPSP lesion. GEL in the intralobular ducts was identified in every case with LNI; although that in the interlobular ducts was observed only focally in one case. There was no difference of age and gender of patients between the two groups and the histological features as well as the number of IgG4-positive plasma cells were otherwise not different.
Conclusions: LNI was commonly observed in cases with otherwise typical LPSP, especially when multiple tissue blocks were examined. In addition, LNI ocurred preferentially at the periphery of the LPSP, indicating that LNI itself may be a different process from LPSP itself. GEL in the intralobular ducts was always observed in the foci with LNI, and this finding should not be used as a diagnostic hallmark of IDCP. On the other hand, GEL in the interlobular ducts was extremely rare in LPSP and is a highly specific feature of IDCP.
Category: Pancreas

Tuesday, March 20, 2012 9:30 AM

Poster Session III # 259, Tuesday Morning


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