Comparison of methylene blue-directed biopsies and conventional biopsies in the detection of intestinal metaplasia and dysplasia in Barrett's esophagus: a preliminary study.

BACKGROUND: The diagnostic advantage of methylene blue (MB) chromoendoscopy in Barrett's esophagus is unclear. METHODS: Patients with columnar-lined esophagus (CLE) were enrolled into a prospective, randomized crossover trial of MB-directed biopsy versus conventional biopsy. RESULTS: Forty-seven patients (19 long-segment CLE; 28 short-segment CLE) were enrolled and underwent MB-directed biopsy. Sensitivity and specificity of MB for specialized intestinal metaplasia were 53% and 51%, respectively. Sensitivity and specificity of MB for dysplasia were 51% and 48%, respectively. Thirty-five patients (15 long-segment CLE; 20 short-segment CLE) completed the crossover trial. Relative frequencies for specialized intestinal metaplasia were 73% and 71% from MB-directed and conventional biopsy specimens, respectively (p = 0.73). Relative frequencies for dysplasia were 20% and 18% from MB-directed and conventional biopsy specimens, respectively (p = 0.65). In patients with long-segment CLE, dysplasia was diagnosed in 10 patients with MB and 7 patients with conventional biopsy methods (p = 0.25). The number of biopsy specimens per EGD was greater with MB, which may have influenced the diagnosis. Histologically, the grade of dysplasia was indefinite/low in nearly all of the dysplastic specimens. CONCLUSIONS: Results of MB-directed biopsy were similar to conventional biopsy in detecting specialized intestinal metaplasia and indefinite/low-grade dysplasia. MB was not useful in short-segment Barrett's esophagus.

Pure red cell aplasia due to parvovirus B19 in a patient treated with rituximab.

Rituximab is a chimeric monoclonal antibody directed against CD20 and used in the treatment of B-cell non-Hodgkin's lymphoma. Due to its ability to deplete B lymphocytes, rituximab can interfere with humoral immunity, causing it to be suppressed for several months after treatment. The reported case depicts a serious consequence of this effect of rituximab therapy: pure red cell aplasia resulting from chronic parvovirus B19 infection. The point of interest in this case is not only the association between rituximab therapy and pure red cell aplasia, but the diagnostic and therapeutic utility of the knowledge of parvovirus B19 as the likely etiologic link between the two. Given the known efficacy of intravenous immunoglobulin (IVIg) in the treatment of chronic parvovirus B19 infection, this therapy can cure some of these patients and successfully render most others transfusion-independent until recovery of their own humoral immune system.

CML blast crisis resulting in biliary obstruction following BMT.

Allogeneic BMT is the treatment of choice for various hematologic malignancies. Despite careful patient scrutiny, a large number of patients experience significant morbidity and mortality due to procedure-related toxicity. Hepatobiliary toxicity presenting as biliary cholestasis, due to the preparative regimen (ie venoocclusive disease), supportive pharmaceuticals, and/or GVHD have been implicated. We report a unique cause of cholestasis in a patient undergoing BMT for CML. The cholestasis was found to be secondary to relapsed leukemia, which resulted in a granulocytic sarcoma obstructing the biliary ductal system.