Rituximab-induced Remission of a Gastric MALT Lymphoma

Synchronous occurrence of gastric adenocarcinoma and MALT-type lymphoma: A case report and literature review

The coexistence of multiple primary malignant tumors in an organ is rare. This includes the extremely rarely reported combination of gastric adenocarcinoma and gastric MALT-type lymphoma as synchronous tumors. We describe a case of a 72-year-old man diagnosed with this combination. He had no remarkable medical history and came to our hospital because of discomfort in the gastric area. Although the biopsy revealed adenocarcinoma only, the microscopic findings after partial gastrectomy incidentally showed additional lymphoma that was subsequently confirmed by immunohistochemistry as MALT-type lymphoma. This case study and literature analysis aims to raise awareness of the possibility of synchronous malignant neoplasm in the stomach to enhance preoperative diagnosis.

Therapeutic antibodies against cancer

Antibody-based therapeutics against cancer are highly successful and currently enjoy unprecedented recognition of their potential; 13 monoclonal antibodies (mAbs) have been approved for clinical use in the European Union and in the United States. Bevacizumab, rituximab, and trastuzumab had sales in 2010 of more than $5 billion each. Hundreds of mAbs, including bispecific mAbs and multispecific fusion proteins, mAbs conjugated with small-molecule drugs, and mAbs with optimized pharmacokinetics, are in clinical trials. However, deeper understanding of mechanisms is needed to overcome major problems including resistance to therapy, access to targets, complexity of biological systems, and individual variations.

Transformation of MALT lymphoma to pure plasma cell histology following treatment with the anti-CD20 antibody rituximab

Mucosa associated lymphoid tissue (MALT) lymphoma is a relatively common lymphoma arising from marginal-zone B-cells which are closely related to plasma cells. As opposed to the large majority of plasma cells, MALT lymphoma cells express CD20, and the anti-CD20 antibody rituximab has been reported as active treatment in patients with MALT lymphoma. We present a patient with MALT lymphoma involving stomach and lung which transformed to a pure plasma cell tumor after therapy with rituximab. This observation again supports the close association between the cell of origin of MALT lymphoma and plasma cells, suggesting that "plasmacytoma of the GI-tract" as anecdotally reported may in fact be a MALT lymphoma with extreme plasmacytic differentiation. In addition, our findings suggest that MALT lymphomas with plasmacytic differentiation might have a different 18F-FDG uptake as compared to classical MALT lymphoma.

Helicobacter pylori eradication in gastric mucosa-associated lymphoid tissue lymphoma: Results of a 196-patient series

Prospective studies have reported ongoing remissions in most patients with localized Helicobacter pylori-positive gastric mucosa-associated lymphoid tissue lymphoma after curing the infection. Using specific selection criteria, the outcome of 196 patients treated in routine clinical practice was analysed. Complete remission rates, stability of remissions and frequency of relapse and histologic residual disease were in accordance with previous prospective clinical trials, whereas the median age was higher. Only a minority had a complete staging, and it may be expected that there is a significant group of patients with an unrecognized higher stage in this cohort. The frequency of follow-up investigations was also not considered as recommended in a considerable number of patients. Nevertheless, the outcome of patients was favourable regardless of limited staging and follow-up procedures. Amended recommendations and special guidelines for elderly and patients with concomitant disease should be considered.

Successful treatment of Helicobacter pylori-negative gastric MALT lymphoma with rituximab

Helicobacter pylori infection is strongly associated with low-grade gastric lymphoma, commonly known as mucosa-associated lymphoid tissue (MALT) lymphoma. H. pylori eradication leads to complete remission in 80% of early stage MALT lymphomas. The treatment for early stage H. pylori-negative gastric MALT lymphoma is evolving. Rituximab, a chimeric anti-CD20 antibody, has shown response rates of approximately 50% with minimal toxicity in patients with B-cell non-Hodgkin lymphoma. We describe herein the clinical, endoscopic, and histologic features of a patient with H. pylori-negative gastric MALT lymphoma treated successfully with rituximab.