Analysis of CD20 alone could be misleading in lineage determination of B-cell lymphomas: A case of CD20 negative diffuse large B-cell lymphoma in abdominal effusion

摘要

Dear Editor, A 36-year-old woman with a history of renal transplantation due to diffuse extracapillary glomerulonephritis in 1995 developed an abdominal effusion, which was diagnostically aspirated in 2007. In addition, enlarged abdominal lymph nodes (up to 2 cm) were sonographically detected. Twenty millili-tres of a haemorrhagic fluid from the abdominal effusion were routinely processed as smears and stained according to the modified Papanicolaou method. In addition, smears were processed and stained with the anti-CD20 antibody (Dako M755, clone 126, dilution 1:800; Dako, Glostrup, Denmark). The specimen was incubated overnight with the complex avidin-biotin-peroxidase without pretreatment. Peroxidase-bound secondary antibody (RTU Vectastain Kit, PK6100; Vector Laboratories, Burlingame, CA, USA) and diam-inobenzidine were used for visualization.