Diagnostic Usefulness of Cell Block Samples in Fluid Overload‐Associated Large B‐Cell Lymphoma
Hiroyuki Okanishi, Hiroko Kuwabara, Hiroko Nakayama, Mayo Odaka, Kozue Ariga, Isako Kataoka, Mari Tomiuka, Mayumi Uragami, Chihiro Deguchi, Shizuka Ono, Reika Takeda, Yoshitaka Kurisu, Yoshinobu Hirose, Yuuki Kinoshita, Taiji YokoteABSTRACT
Fluid overload‐associated B‐cell lymphoma (FO‐LBCL) is a B‐cell neoplasm that presents as serous effusions without detectable tumor masses and Kaposi sarcoma‐associated herpesvirus (KSHV)/human herpesvirus 8 (HHV8) infection. Here, we report a case of an 81‐year‐old female patient with FO‐LBCL (Stage IVA) who presented with pericardial and pleural effusions. The patient had no underlying medical condition that could lead to fluid overload. Cytological examination of both effusions revealed medium‐ to large‐sized lymphoid cells with high nucleocytoplasmic ratios, irregular nuclei, dense chromatin, prominent nucleoli, mitotic figures, basophilic cytoplasm, and lymphoglandular bodies. A cell block of the pleural fluid effusion showed that atypical lymphoid cells were positive for CD20 and CD79a, and negative for CD3, KSHV/HHV‐8, and Epstein–Barr virus. The Ki‐67 labeling index was 95%. The patient underwent systemic chemotherapy and achieved complete remission without pleural or pericardial recurrence during the 3‐year follow‐up period. As FO‐LBCL is diagnosed based on cytological material, together with clinical and imaging findings, immunohistochemical analysis of the cell block is useful for confirming the diagnosis and selecting tailored therapies.