A 62-year-old man was admitted to our hospital with left-sided chest and back pain and dyspnea. He had a history of asbestos exposure when he worked as a pipe fitter and wrecker for more than 30 years without a history of tuberculosis. Results of blood analysis were as follows: white blood cell count, 8.30 x 109/L (66.3% neutrophils, 17.5% lymphocytes); hemoglobin, 105 g/L; platelet count, 683 x 109/L; lactate dehydrogenase, 411 IU/L; and C-reactive protein, 3.80 mg/dL. Whole body computed tomography (CT) showed the marked circumferential left pleural thickening, and pleural effusion in the left chest (Fig. 1(A)). Fluorodeoxyglucose positron emission tomography (FDG-PET)/CT, performed after 10 days, revealed the progressively increased pleural thickening with an intense FDG uptake (Fig. 1(B)). A thoracoscopic pleural biopsy showed the dense proliferation of lymphoblastoid cells, which were medium- to large-sized with conspicuous nucleoli. Tingible body macrophages were scattered among them, representing a "starry sky" appearance (Fig. 2(A)). Immunohistochemical analysis revealed that the lymphoblastoid cells were positive for CD20, CD79a, BCL2, and BCL6, but negative for CD3, CD5, CD10, MUM1, cyclin D1, and TdT. The lymphoblastoid cells were also positive for tumor necrosis factor (TNF) (52B83; Santa Cruz Biotechnology, Santa Cruz, CA) (Fig. 2(B)) and interleukin-6 (IL-6) (10C12; Novocastra, Newcastle Upon Tyne, UK) (Fig. 2(C)). In situ hybridization for Epstein-Barr-encoded RNA was negative. The proliferation index, as assessed by Ki67 (30-9; Ventana Medical Systems, Tucson, AZ) (Fig. 2(D)), was approximately 90%. Fluorescence in situ hybridization analysis did not detect MYC rearrangement. Southern blotting revealed clonal rearrangement of the immunoglobulin heavy chain gene (Fig. 3). The patient was eventually diagnosed with HGBL, NOS, according to the 2017 WHO classification. Following treatment with 2 courses of R-CHOP therapy (a regimen of rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisolone), the pleural thickening reduced. But after 3 courses of R-CHOP therapy, the tumor enlarged again. Following salvage chemotherapy with 3 courses of R-Hyper CVAD/MA therapy (a regimen of rituximab, hyper-fractionated cyclophosphamide, vincristine, doxorubicin and dexamethasone alternating with rituximab, methotrexate and cytarabine), the tumor disappeared (Fig. 1(C)).
Radiological findings of CT. (A) CT scan on admission, demonstrating marked circumferential left pleural thickening, and pleural effusion in the left chest.