[1758] Poorly Cohesive Cell (Diffuse-Infiltrative/Signet-Ring) Carcinomas of the Gallbladder (GB): Clinicopathologic Analysis of 24 Cases Identified in 628 GB Carcinomas

Samip Patel, Juan Carlos Roa, Pelin Bagci, Oscar Tapia, Kee-Taek Jang, Matthew Lim, Nevra Dursun, Burcu Saka, Leslie Ducato, Olca Basturk, Juan Sarmiento, N Volkan Adsay. Emory U, Atlanta; UFRO, Temuco, Chile; MSKCC, New York

Background: There is virtually no data on the gallbladder counterparts of carcinomas with single-cell or cord-like infiltration, previously called “diffuse-infiltrative” type or “signet-ring cell” (SRC), and now designated as “poorly cohesive cell” (PCC) type in the WHO-2010 classification(Fig 1).

Design: 628 invasive GB CA were reviewed. 24 cases in which classical PCC/SRC pattern constituted > 50% of the tumor were subjected to detailed analysis and contrasted with ordinary GBCs. Excluded were 18 cases in which PCC pattern was focal (<50%), and 8 with dyshesive SRCs floating within the mucin but not infiltrating into the stroma.
Results: F/M=19/3=6.3. Mean age=63. Gross and low-power findings were highly akin to “linitis plastica”. Cytologic features varied from small bland-monotonous cells resembling that of “invasive lobular breast ca”, to high-grade with pleomorphic nuclei, with coarse chromatin and prominent nucleoli, akin to those of “urothelial plasmacytoid” ca. All cases showed at least focal signet-ring morphology and this was predominant in 50%. Most cases had advanced carcinoma (pT3+, 79% vs 51%; p<0.01). 4/6 cases with LNs available showed mets (vs 38%; p=0.3). While perineural invasion was high (74 vs 38%; p<0.01), vascular invasion was present only in 8 cases (33 vs 72%; p<0.01). The clinical course appeared to be even more aggressive than ordinary GBC (median surv., 3.3 vs 11.8 mos; p=0.06 by log rank test; Fig 2).

Conclusions: Gallbladder counterpart of the carcinoma type that is now classified as “poorly cohesive cell” by the WHO-2010 (previously called “diffuse-infiltrative/signet-ring cell”) occurs in 3.8 % of cases with GBC. It is seen almost exclusively in women and appears to have a more aggressive clinical course than ordinary GBC.
Category: Liver

Monday, March 19, 2012 9:30 AM

Poster Session I Stowell-Orbison/Surgical Pathology/Autopsy Awards Poster Session # 266, Monday Morning


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