title: CD27-positive hairy cell leukemia-Japanese variant.
abstract: We report a very rare case of a 45-year-old Japanese male patient with hairy cell leukemia-Japanese variant (HCL-JV) expressing CD27. The patient showed a high number of abnormal peripheral lymphocytes, thrombocytopenia, and severe splenomegaly but no lymphadenopathy. Histology of the resected spleen showed small-sized lymphoma cells diffusely infiltrating the red pulp without follicle formation. By immunohistochemistry, lymphoma cells were negative for CD3, CD5, CD8, CD10, CD34, cyclin-D1, and annexin A1 but positive for CD20 and BCL2. BRAF V600E mutation was not observed. Bone marrow aspirate showed preserved normal hematopoietic cells with invasion of lymphoma cells in an interstitial pattern without obvious nodules. The cells had abundant pale cytoplasm and round nuclei with inconspicuous nucleoli. After natural drying, the cells had unevenly distributed microvilli. Flow cytometric analysis demonstrated positivity for CD11a, CD11c, CD19, CD20, CD22, CD27, surface IgG, and λ but not for CD2, CD3, CD4, CD5, CD7, CD8, CD10, CD21, CD23, CD25, CD30, CD34, CD38, CD43, CD56, CD57, CD103, IgD, IgM, and κ. Monoclonal expansion of B cells was confirmed by an immunoglobulin heavy chain (IgH) rearrangement band as demonstrated by Southern blot hybridization. The lymphoma cells had unevenly distributed long, large, and broad-based microvilli, which resembled splenic diffuse red pulp small B cell lymphoma (SDRPL) cells. CD27 expression is extremely rare in HCL-JV, but the young age of the patient and high peripheral WBC counts were similar to HCL-JV, which suggests, in this case, an intermediate disease between SDRPL and HCL-JV.
authors: Department of Hematology and Oncology, Hyogo Prefectural Tsukaguchi Hospital, Hyogo, Japan. rtabata@hp.pref.hyogo.jp.|Department of Hematology and Oncology, Hyogo Prefectural Amagasaki General Medical Center, 2-17-77 Higashinaniwa-cho, Amagasaki, Hyogo, 660-8550, Japan. rtabata@hp.pref.hyogo.jp.
authors: Rie
authors: R
authors: Tabata
authors: Hyogo College of Medicine Cancer Center, Hyogo, Japan.
authors: Chiharu
authors: C
authors: Tabata
authors: Department of Surgery, Hyogo Prefectural Tsukaguchi Hospital, Hyogo, Japan.
authors: Hideaki
authors: H
authors: Iwama
authors: Department of Pathology, Hyogo Prefectural Tsukaguchi Hospital, Hyogo, Japan.
authors: Ryoji
authors: R
authors: Yasumizu
authors: Department of Anatomic and Diagnostic Pathology, Dokkyo Medical University School of Medicine, Tochigi, Japan.
authors: Masaru
authors: M
authors: Kojima
mesh_terms: D001402:B-Lymphocytes / Q000276:immunology / Q000473:pathology*; D006801:Humans; D007150:Immunohistochemistry / Q000379:methods; D016130:Immunophenotyping / Q000379:methods; D007943:Leukemia, Hairy Cell / Q000276:immunology / Q000378:metabolism*; D016393:Lymphoma, B-Cell / Q000276:immunology / Q000473:pathology; D008297:Male; D008875:Middle Aged; D013160:Splenic Neoplasms / Q000175:diagnosis* / Q000276:immunology / Q000473:pathology; D018127:Tumor Necrosis Factor Receptor Superfamily, Member 7 / Q000378:metabolism
chemical_list: D018127:Tumor Necrosis Factor Receptor Superfamily, Member 7
keywords: CD103; CD25; CD27; Hairy cell leukemia; Splenic lymphoma