Apart from the phenotypical difference, our HHV8-positive neoplasms were not distinct from the HHV8-negative group. Literature review of 256 cases, including our cases, revealed that HHV8-positive cases were associated more frequently with HIV and EBV infection, with rare MYC rearrangement, and a poorer prognosis than HHV8-negative cases. We propose to name the HHV8-positive cases as 'classical' or 'type I PEL' and the HHV8-negative cases as 'type II PEL', stressing the similarities and the distinctive features between these two groups.

This report presents the clinical, cytological and molecular features of pleural effusion lymphoma which developed in a patient treated for chronic myeloid leukaemia after five years of dasatinib therapy. The effusion lymphoma recurred three times but largely resolved after pleurocentesis and steroid treatment. More reports on such unusual cases may improve our understanding and management of patients with this rare adverse effect associated with dasatinib.

Abstract. CD44 plays a major role in multiple physiological processes, including cell-cell adhesion, cell-substrate interaction, lymphocyte homing, and tumor metastasis. It has been reported that highly expressed CD44 in certain types of tumors is associated with the hematogenic spread of tumor cells. The ability of CD44 to bind hyaluronan has been shown to correlate with tumor cell invasiveness, and it is likely that this ability may enhance tumor cell migration at several points during metastasis. However, the mechanism as to how CD44 stimulates metastasis remains unknown. The human breast tumor cell line, MDA-MB-435s, was used to investigate the effect of antibody-mediated CD44 crosslinking on the cellular level and localization of matrix metalloproteinase-9 (MMP-9). Confocal microscopy and immunocytochemical analyses were performed to demonstrate colocalization of CD44 and MMP-9 after CD44 crosslinking. Furthermore, the CD44-MMP-9 complex was purified by immunoprecipitation. G8 myoblast monolayers were employed to evaluate the invasiveness of human breast tumor cells after CD44 crosslinking in the presence or absence of protease inhibitors. CD44 crosslinking augmented the level of MMP-9 in the membrane of human breast tumor cells and clustering of CD44 serves as an MMP-9 docking molecule allowing MMP-9 to retain its concentrated proteolytic activity on the cell surface. Furthermore, crosslinking of CD44 enhances the ability of breast tumor cells to invade G8 myoblast monolayers and migrate through the basal membranes which was inhibited in the presence of anti-MMP-9 antibody or the MMP inhibitors GM6001 or 1,10-phenanthroline. This study demonstrates for the first time that CD44 crosslinking leads to an enhanced level and relocation of MMP-9 in human breast tumor cells accompanied by increased tumor invasion and metastasis.

Effusion-based lymphoma is a rare and unique type of large B-cell lymphoma presenting in effusion without a mass lesion. It shares many clinicopathological features with primary effusion lymphoma (PEL), but is distinct from PEL by the absence of HHV8 association. Double hit lymphoma (DHL) is an aggressive B-cell lymphoma, defined by concurrent rearrangement of MYC and BCL2 or BCL6. DHL often presents as lymphadenopathy or an extranodal mass, but rarely occurs in effusion. Here we report a 61-year-old male with alcoholic cirrhosis presenting as massive ascites and left pleural effusion. He has no HIV, HBV or HCV infection and no mass lesion by CT scans. Cytology of both pleural effusion and ascites show large lymphoma cells with plasmablastic morphology characterized by pleomorphic and eccentric nuclei, prominent nucleoli and frequent mitoses. Immunohistochemical study with cell block shows that the lymphoma cells express plasma cell-related markers (CD138, MUM-1 and EMA), but not CD3, CD30, CD45, B-cell markers (CD19, CD20, CD79a, and PAX5), HHV8, ALK or cytokeratin. EBER is positive in most lymphoma cells. Fluorescence in situ hybridization reveals rearrangement at the IGH, BCL2, and MYC loci, but not at BCL6. It is diagnosed as an EBV-associated but HHV8-unrelated double hit effusion-based lymphoma with plasmablastic features. The patient passed away soon after diagnosis without chemotherapy. This is the first reported case of double-hit effusion-based lymphoma with MYC and BCL2 rearrangement. This case illustrates the importance of integrating clinical, cytological, immunophenotypical, and molecular findings to reach a correct diagnosis. Diagn. Cytopathol. 2017;45:257-261. © 2016 Wiley Periodicals, Inc.

This study retrospectively investigated 54 cases of sporadic Burkitt lymphoma in Taiwan with histopathology review, immunohistochemistry, Epstein-Barr virus (EBV) in situ hybridization (EBER) and fluorescence in situ hybridization (FISH). The great majority revealed typical immunophenotype and 89% (47/53) cases expressed myc protein. EBER was positive in 20% (11/54) of cases, more frequently with nodal presentation, but not significantly associated with age (pediatric vs. adult), abdominal vs. extra-abdominal presentation or overall survival (OS). MYC and IGH were rearranged in 94% (46/49) and 85% (41/48) of cases, respectively. The concordance rate between myc expression and MYC translocation was 83% (40/48). By univariate analysis, OS was statistically associated with age, with or without chemotherapy, central nervous system (CNS) involvement, CNS prophylaxis and leukemic transformation, but not gender, nodal vs. extranodal involvement, stage, immunohistochemistry, EBER, myc expression, MYC translocation or radiotherapy. By multivariate analysis, CNS involvement at presentation and administration of chemotherapy were statistically associated with OS.