Anaplastic lymphoma kinase-positive large B-cell lymphoma: a case report with emphasis on the cytological features of the pleural effusion.

Anaplastic lymphoma kinase (ALK)-positive large B-cell lymphoma (ALK-positive LBCL) is an extremely rare distinct clinicopathological subtype of LBCL, characterized by the presence of ALK-positive monomorphic large immunoblast-like neoplastic B cells. Herein, we describe the first cytological report on ALK-positive LBCL in the pleural effusion. A 69-year-old Japanese male with a past history of malignant lymphoma of the cecum presented with progressive dyspnea and pleural effusion. Removal of the pleural effusion and aspiration of bone marrow were performed. May-Grünwald-Giemsa stain of the pleural fluid revealed abundant single or small aggregates of large-sized round cells. These cells had centrally-located large round to oval nuclei. The peculiar finding was the presence of pseudopodial cytoplasmic projections, and some neoplastic cells had eosinophilic pseudopodial cytoplasmic projections, which resembled "flaming plasma cells". Histopathological and immunohistochemical studies of the bone marrow demonstrated CD138(+), ALK1(+), CD20(-), CD79a(-), CD30(-), and IgA(+) large-sized neoplastic cells. Therefore, a diagnosis of ALK-positive LBCL was made. The peculiar finding of the present case was that most of the neoplastic cells had pseudopodial cytoplasmic projections, and some of them had eosinophilic pseudopodial cytoplasmic projections that resembled "flaming plasma cells", which has been recognized as the characteristic finding of IgA myeloma. Therefore, tumor cells that resembled "flaming plasma cells" in the pleural effusion may have had IgA in the cytoplasm. Albeit extremely rare, ALK-positive LBCL shows aggressive clinical course, thus, recognition of the cytomorphological features of this type of malignant lymphoma is important for early and correct diagnosis.

Hairy cell transformation of human peripheral blood lymphocytes by Coxiella burnetii

Hairy cell (HC) transformation of human peripheral blood lymphocytes (PBL) by Coxiella burnetii was studied to clarify the significance of persistency of C. burnetii in a hairy cell line (designated "TOL"). TOL cells which exhibited HC characteristics in hairy cell leukemia (HCL) were persistently infected with C. burnetii. Two strains of C. burnetii, our isolate from TOL cells and the original isolate in 1935, the Nine Mile strain from American Type Culture Collection (ATCC, U.S.A), were inoculated to PBL cultures. HC transformation not only by our isolates (87%) but also by Nine Mile strain (100%) was demonstrated in an average of 20 days. The original observation that Coxiella induced HC transformation in vitro was also confirmed in experiments with PBL exposed to C. burnetii in vivo. Spontaneous development of HC were observed in cultures of PBL only from coxiellemic cases (12/24) but not from C. burnetii negative cases (0/57). All HC cell lines (34) as determined by their morphology and cytochemical markers of HC in HCL remained infected with C. burnetii invariably.