An unusual case of Primary Effusion Lymphoma with aberrant T-cell phenotype in a HIV-negative, HBV-positive, cirrhotic patient, and review of the literature

Recent Advances in Aggressive Large B-cell Lymphomas: A Comprehensive Review

Diffuse large B-cell lymphoma (DLBCL) is an aggressive disease with considerable heterogeneity reflected in the 2008 World Health Organization classification. In recent years, genome-wide assessment of genetic and epigenetic alterations has shed light upon distinct molecular subsets linked to dysregulation of specific genes or pathways. Besides fostering our knowledge regarding the molecular complexity of DLBCL types, these studies have unraveled previously unappreciated genetic lesions, which may be exploited for prognostic and therapeutic purposes. Following the last World Health Organization classification, we have witnessed the emergence of new variants of specific DLBCL entities, such as CD30 DLBCL, human immunodeficiency virus-related and age-related variants of plasmablastic lymphoma, and EBV DLBCL arising in young patients. In this review, we will present an update on the clinical, pathologic, and molecular features of DLBCL incorporating recently gained information with respect to their pathobiology and prognosis. We will emphasize the distinctive features of newly described or emerging variants and highlight advances in our understanding of entities presenting a diagnostic challenge, such as T-cell/histiocyte-rich large B-cell lmphoma and unclassifiable large B-cell lymphomas. Furthermore, we will discuss recent advances in the genomic characterization of DLBCL, as they may relate to prognostication and tailored therapeutic intervention. The information presented in this review derives from English language publications appearing in PubMed throughout December 2015. For a complete outline of this paper, please visit: http://links.lww.com/PAP/A12.

KSHV viral cyclin interferes with T-cell development and induces lymphoma through Cdk6 and Notch activation in vivo

Kaposi's sarcoma herpesvirus (KSHV)-encoded v-cyclin, a homolog of cellular cyclin D2, activates cellular CDK6, promotes G1-S transition of the cell cycle, induces DNA damage, apoptosis, autophagy and is reported to have oncogenic potential. Here we show that in vivo expression of v-cyclin in the B- and T-cell lymphocyte compartments results in a markedly low survival due to high penetrance of early-onset T-cell lymphoma and pancarditis. The v-cyclin transgenic mice have smaller pre-tumorigenic lymphoid organs, showing decreased cellularity, and increased proliferation and apoptosis. Furthermore, v-cyclin expression resulted in decreased amounts of CD3-expressing mature T-cells in the secondary lymphoid organs concurrent with alterations in the T-cell subpopulations of the thymus. This suggests that v-cyclin interferes with normal T-cell development. As the Notch pathway is recognized for its role in both T-cell development and lymphoma initiation, we addressed the role of Notch in the v-cyclin-induced alterations. Fittingly, we demonstrate induction of Notch3 and Hes1 in the pre-tumorigenic thymi and lymphomas of v-cyclin expressing mice, and show that lymphoma growth and viability are dependent on activated Notch signaling. Notch3 transcription and growth of the lymphomas was dependent on CDK6, as determined by silencing of CDK6 expression or chemical inhibition, respectively. Our work here reveals a viral cyclin-CDK6 complex as an upstream regulator of Notch receptor, suggesting that cyclins can play a role in the initiation of Notch-dependent lymphomagenesis.

Primary effusion lymphoma with aberrant T-cell phenotype in an iatrogenically immunosuppressed renal transplant male: cytologic diagnosis in peritoneal fluid

Primary effusion lymphoma (PEL) is an unusual class of non-Hodgkin's lymphoma that develops in body cavities, without associated mass lesions. It has been linked to human herpes virus 8 (HHV-8), an etiological factor of Kaposi's sarcoma. Although PEL is a B-cell lymphoma, the neoplastic cells are usually of the "null" phenotype by immunocytochemistry. The relative infrequency of this entity, the absence of wide casuistic allowing a better characterization, and its unfavorable outcome, strongly support the need of a deeper knowledge. We report the clinico-biological findings of a 49-year-old male who was iatrogenically suppressed patient for 29 years because of renal transplantation. This case was diagnosed cytologically as peritoneal PEL and confirmed histologically on peritoneal biopsies. The immune status for both HHV-8 and Epstein-Barr virus (EBV) was evaluated and showed positive immunostaining only for the former. The combination of the immunocytochemistry results with the existence of a clonal rearrangement in the immunoglobulin heavy chain gene (identified by PCR) was compatible with the diagnosis of PEL. The presence of T-cell markers was consistent with the diagnosis of PEL with an aberrant T-cell phenotype.