Increased Plasmacytic Differentiation in Gastric Mucosa-associated lymphoid tissue Lymphomas: H. pylori Eradication Response and IgG4+ Plasma Cell Association

• Published in: Human pathology 2016
• Main Authors: Park, Sanghui, MD, PhD, Ahn, Soomin, MD, Hong, Mineui, MD, Ko, Young Hyeh, MD, PhD
• Format: Article
• Language: English
• Subjects: Pathology
• ISSN: 0046-8177
• DOI: 10.1016/j.humpath.2016.09.013

Gastric mucosa-associated lymphoid tissue (MALT) lymphoma is a rare extranodal marginal zone B-cell lymphoma that is often associated with plasmacytic differentiation. However, the clinicopathologic characteristics of gastric MALT lymphoma with increased plasmacytic differentiation have not yet been studied. To assess the clinicopathologic implications of gastric MALT lymphoma with increased plasmacytic differentiation, thirty-six cases with increased plasmacytic differentiation and a control group of 16 cases with minimal plasmacytic differentiation were retrospectively collected from 65 primary gastric MALT lymphomas (2010~ 2012). The hematoxylin and eosin (H&E) slides were reviewed, and IgG, IgG4, κ and λ immunohistochemical staining was performed. Clinicopathologic differences between the two groups were compared using the Chi-square test and odd ratios. Logistic regression analyses were used to evaluate resistance to H. pylori eradication therapy. Increased plasmacytic differentiation is significantly correlated with the H. pylori eradication response (94.4% vs. 66.7%, P = .018), lower frequency of relapse (5.6% vs. 35.7%, P = .014), the presence of more than one IgG4+ cell per high power field (HPF) (27.8% vs. 0%, P = .022) and light chain restriction (33.3% vs. 6.2%, P = .044). Univariable logistic regression indicated that negative H. pylori status (P = .016) and minimal plasmacytic differentiation (P = .019) were statistically significant predictive factors for resistance to H. pylori eradication. Multivariable logistic regression analyses identified no statistically significant predictive factors. However, H. pylori negativity and minimal plasmacytic differentiation showed a statistical trend toward significance (P = .078 and P = .09). Gastric MALT lymphomas with increased plasmacytic differentiation have different clinicopathologic characteristics and plasmacytic differentiation is associated with H. pylori eradication response.