Lymphoproliferative Neoplasms With Plasmablastic Morphology: An Overview and Diagnostic Approach

Plasmablastic myeloma transformation of light-chain multiple myeloma

Plasmablastic myeloma (PBM) is an uncommon and aggressive morphologic variant of multiple myeloma (MM). The neoplastic immature cells exhibit diverse morphology, posing a diagnostic challenge. The diagnostic criteria for PBM include the identification of ≥ 2% plasmablasts in the bone marrow aspirate. This case describes the incidental finding of a light-chain multiple myeloma (LCMM) transformed into PBM, a phenomenon not previously reported.

Plasmablastic Lymphoma. A State-of-the-Art Review: Part 1-Epidemiology, Pathogenesis, Clinicopathologic Characteristics, Differential Diagnosis, Prognostic Factors, and Special Populations

This two-part review aims to present a current and comprehensive understanding of the diagnosis and management of plasmablastic lymphoma. The first section, as presented in this paper, reviews epidemiology, etiology, clinicopathological characteristics, differential diagnosis, prognostic variables, and the impact of plasmablastic lymphoma on specific populations. Plasmablastic lymphoma (PBL) is a rare and aggressive form of lymphoma. Previous and modern studies have demonstrated a significant association between the human immunodeficiency virus (HIV) and the development of the disease. The limited occurrence of PBL contributes to a need for a more comprehensive understanding of the molecular mechanisms involved in its etiology. Consequently, the diagnostic procedure for PBL poses a significant difficulty. Among the group of CD20-negative large B-cell lymphomas, PBL can be correctly diagnosed by identifying its exact clinical characteristics, anatomical location, and morphological characteristics. PBL cells do not express CD20 or PAX5 but possess plasmacytic differentiation markers such as CD38, CD138, MUM1/IRF4, Blimp1, and XBP1. PBL must be distinguished from other B-cell malignancies that lack the CD20 marker, including primary effusion lymphoma, anaplastic lymphoma kinase-positive large B-cell lymphoma, and large B-cell lymphoma (LBCL). This condition is frequently associated with infections caused by the Epstein-Barr virus and genetic alterations involving the MYC gene. Despite advances in our comprehension of this disease, the prognosis remains dismal, resulting in a low overall survival rate, although recent reports suggest an apparent tendency towards substantial improvement.

Quiz case: Abnormal haematopoietic cells in pleural effusion

This case was presented because of the number of plasmablasts in a patient with a medical history of multiple myeloma. Flow cytometry is a "gold standard" technique for the diagnosis of haematological malignancies. This technique works for all fluids and should be performed in effusions (pleural, pericardial, ascites) in cases of suspected haematological malignancy. Alternatively, immunohistochemistry using appropriate markers could be performed if flow cytometry is not available. This case illustrates a pleural infiltration by plasmablasts. Myelomatous cells were characterised by immunocytochemistry and flow cytometry.

Cardiac Involvement by Human Herpesvirus 8-Positive Diffuse Large B-Cell Lymphoma: An Unusual Presentation in a Patient with Human Immunodeficiency Virus

Human immunodeficiency virus (HIV) infection predisposes patients to the development of lymphomas, both due to immune suppression and coinfection with viruses with oncogenic potential. Coinfection with human herpesvirus 8 (HHV8) in particular has been associated with the development of aggressive lymphomas, including primary effusion lymphoma and diffuse large B-cell lymphoma (DLBCL). Herein, we report an unusual case of HHV8-positive DLBCL with extensive cardiac involvement which was diagnosed at autopsy in a patient with long-standing untreated HIV infection.