Primary mediastinal B-cell lymphoma

A type of non-Hodgkin lymphoma

Primary mediastinal B-cell lymphoma (PMBCL) is a subtype of diffuse large B-cell lymphoma (DLBCL), which is a type of non-Hodgkin lymphoma. It is characterized by the presence of a mass in the mediastinum, the central compartment of the thoracic cavity. PMBCL primarily affects young adults, with a higher prevalence in females.

Pathophysiology

PMBCL originates from B-cells, a type of white blood cell that plays a crucial role in the immune response. These B-cells undergo malignant transformation and proliferate uncontrollably, forming a tumor in the mediastinum. The exact cause of this transformation is not fully understood, but it involves genetic mutations and alterations in signaling pathways that regulate cell growth and survival.

Clinical Presentation

Patients with PMBCL typically present with symptoms related to the mass effect of the tumor in the mediastinum. Common symptoms include:

• Cough
• Dyspnea (shortness of breath)
• Chest pain
• Superior vena cava syndrome, which results from compression of the superior vena cava and leads to swelling of the face and arms, and distended neck veins.

Diagnosis

The diagnosis of PMBCL involves a combination of clinical evaluation, imaging studies, and histopathological examination.

Imaging

Primary mediastinal large B-cell lymphoma - very high magnification

Imaging studies such as chest X-ray, computed tomography (CT) scan, and positron emission tomography (PET) scan are used to assess the size and extent of the mediastinal mass.

Histopathology

A biopsy of the mediastinal mass is essential for definitive diagnosis. Histopathological examination reveals large atypical B-cells with a diffuse growth pattern. Immunohistochemistry is used to confirm the B-cell origin of the tumor by demonstrating the expression of B-cell markers such as CD20.

Treatment

The treatment of PMBCL typically involves a combination of chemotherapy and radiation therapy.

Chemotherapy

The standard chemotherapy regimen for PMBCL is R-CHOP, which includes:

• Rituximab
• Cyclophosphamide
• Doxorubicin
• Vincristine
• Prednisone

Radiation Therapy

Radiation therapy may be used in conjunction with chemotherapy to improve local control of the disease, especially in cases where there is residual disease after chemotherapy.

Prognosis

The prognosis for patients with PMBCL has improved significantly with modern treatment regimens. The overall survival rate is favorable, particularly for patients who achieve complete remission after initial therapy.

Related pages

• Diffuse large B-cell lymphoma
• Non-Hodgkin lymphoma
• Mediastinum