Primary mediastinal large B-cell lymphoma overview

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief:

Primary mediastinal large B-cell lymphoma (PMBCL) is a subtype of diffuse large B-cell lymphoma (DLBCL). It is also considered a distinct type of non-Hodgkin lymphoma (NHL) in the World Health Organization (WHO) classification system. It occurs in the thymus gland. The small gland in the center of the chest behind the sternum where lymphocytes mature, multiply and become _{T cells}. or lymph nodes in the center of the chest. On microscopic histopathological analysis, large-sized cells and alveolar fibrosis are characteristic findings of primary mediastinal large B-cell lymphoma. The incidence of primary mediastinal large B-cell lymphoma increases with age; the median age at diagnosis is 35 years. The symptoms of the primary mediastinal large B-cell lymphoma include fever, weight loss, night sweats, skin rash, facial swelling, cough, shortness of breath, and painless swelling in the neck, axilla, groin, thorax, or abdomen. Lymph node or mediastinal mass biopsy is diagnostic of primary mediastinal large B-cell lymphoma. The predominant therapy for primary mediastinal large B-cell lymphoma is chemotherapy. Adjunctive radiotherapy, stem cell transplant, and biological therapy may be required. The optimal therapy for primary mediastinal large B-cell lymphoma depends on the clinical presentation.

There is no established system for the classification of primary mediastinal large B-cell lymphoma. However it was designated as a separate disorder in 2001 by World health organization. There are different stages of primary mediastinal large B-cell lymphoma, depending on the metastatic stage of disease.

Primary mediastinal large B-cell lymphoma arises from thymus. The small gland in the center of the chest behind the sternum where lymphocytes mature, multiply and become T cells. or lymph nodes in the center of the chest. On microscopic histopathological analysis, large-sized cells and alveolar fibrosis are characteristic findings of primary mediastinal large B-cell lymphoma. The incidence of primary mediastinal large B-cell lymphoma increases with age. The pathophysiology primarily involves constitutional activation of JAK2 pathway through different genetic mechanisms involved.

The cause of primary mediastinal large B-cell lymphoma has not been identified.

Primary mediastinal large B-cell lymphoma must be differentiated from other diseases that cause swollen face, superior vena cava syndrome, and fever, night sweats and weight loss such as hodgkin’s lymphoma, thymoma, and other non hodgkin’s lymphomas.

Primary mediastinal large B-cell lymphoma represents 4% of overall non-hodgkins lymphomas and affects females predominantly.

There are no established risk factors for Primary mediastinal large B-cell lymphoma.

According to the the U.S. Preventive Service Task Force (USPSTF), there is insufficient evidence to recommend routine screening for primary mediastinal large B-cell lymphoma.