A woman, aged 61, had a colonoscopy because of a positive result from a fecal occult blood test. No abnormalities were detected in the colon but endoscopic examination of the terminal ileum showed multiple polypoid lesions (Fig. 1). Indigo carmine dye was then sprayed over the area to determine the presence or absence of intestinal villi. No villi were seen (Fig. 2). In contrast, nodules in the terminal ileum associated with lymphoid hyperplasia have normal villi on the mucosal surface as shown in the upper left panel. Biopsies revealed a diffuse infiltrate of small centrocyte-like cells and lymphoepithelial lesions. Immunohistochemical stains showed that the atypical cells were positive for CD20 and CD79a but negative for CD3, CD5, CD10 and cyclin D1. A computed tomography scan of the abdomen showed mesenteric lymphadenopathy around the terminal ileum. A positron emission tomography scan using 18fluorine-fluorodeoxyglucose was also abnormal with significant accumulation in the right lower quadrant of the abdomen. The patient was diagnosed as having an extranodal, marginal zone B-cell lymphoma of the mucosa-associated lymphoid tissue (MALT), at stage II in the revised European-American lymphoma classification. The term MALT lymphoma has been used to describe a marginal zone B-cell lymphoma derived from gastrointestinal lymphoid tissue. In the stomach, MALT lymphoma is strongly associated with Helicobacter pylori. MALT lymphomas are rare in other regions of the gastrointestinal tract and there are only isolated reports of endoscopic features. A particular characteristic is the disappearance of intestinal villi, perhaps because lymphoma cells disturb the differentiation or migration of cells that arise from the intestinal crypts. As certain microorganisms may be involved in the development of MALT lymphomas of the small bowel, the patient was treated with antibiotics for 1 week. However, the appearance of the lymphoma was unchanged on follow-up colonoscopy and the patient was subsequently treated by chemotherapy. MALT lymphomas of the small bowel have a similar indolent course to MALT lymphomas of the stomach, but predisposing factors are less clear and there is debate about the relative merits of surgery and chemotherapy.
Primary low-grade mucosa-associated lymphoid tissue (MALT) lymphoma of the stomach has a potential to transform to high-grade diffuse large B-cell lymphoma (DLBCL). However, the clonal relation between MALT lymphoma and de novo DLBCL is still controversial. We report here three patients with Helicobacter pylori (H. pylori)-positive gastric MALT lymphoma rapidly progressing to DLBCL at the same site after successful eradication of H. pylori. Although MALT lymphomas in our cases did not possess t(11; 18)(q21;q21), sequence analysis of the rearranged immunoglobulin heavy chain gene showed no clonal relation between preceding MALT lymphoma cells and de novo DLBCL cells at the same site. These findings question the scenario of direct clonal progression of low-grade MALT lymphomas without t(11; 18)(q21;q21) to DLBCL and serve as a reminder of the risk of the progression of DLBCL with a distinct clonality immediately after H. pylori eradication for low-grade MALT lymphoma.
Objective Pneumocystis pneumonia (PCP) is one of the most common opportunistic infections. In systemic autoimmune disease patients receiving immunosuppressive treatments, low lymphocyte count, old age and coexisting lung disease have been known as risk factors for the occurrence of PCP. However, factors relevant to prognosis of PCP have not been fully studied. Methods A total of 95 sequential patients who developed PCP during immunosuppressive treatment for systemic autoimmune diseases was identified from five Japanese centres. We retrospectively assessed baseline characteristics, immunosuppressive treatment prior to the onset of PCP, treatment for PCP and survival. Univariate and multivariate analyses were performed to identify prognostic factors. Results Forty-two deaths (44.2%) were observed in this study. Age at the diagnosis of PCP was higher in non-survivors than in survivors (74 years vs. 64 years, p = 0.008). Non-survivors more frequently had lung involvement than did survivors (47.6% vs. 13.2%, p<0.001). Median lymphocyte count at the diagnosis of PCP was lower in non-survivors than in survivors (499/μl vs. 874/μl, p = 0.002). Multivariate analysis identified lower lymphocyte count, older age and coexisting lung disease at the diagnosis of PCP as independent risk factors for death. Those risk factors for death were similar to the known risk factors for the occurrence of PCP. Conclusion Although PCP can occur even in patients without these risk factors, our data demonstrate that the overall prognosis of PCP in such patients is good. Given that the standard prophylactic treatment against PCP has safety issues, the risk-stratified use of prophylactic treatment may be advisable.
