Primary mediastinal large B-cell lymphoma natural history, complications and prognosis

Primary mediastinal large B-cell lymphoma is usually a fast-growing lymphoma. Patients often have localized disease in the chest at first. If left untreated, primary mediastinal large B-cell lymphoma can causeshortness of breath, cough, chest pain. Primary mediastinal large B-cell lymphoma can also partially block superior vena cava that carries blood from the upper body to the heart and causes superior vena cava syndrome.

• Primary mediastinal large B-cell lymphoma is usually a fast-growing lymphoma.
• Patients often have localized disease in the chest at first.
• If left untreated, primary mediastinal large B-cell lymphoma can cause:
  • shortness of breath
  • cough
  • chest pain
• Primary mediastinal large B-cell lymphoma can also partially block the main vein (superior vena cava) that carries blood from the upper body to the heart and cause superior vena cava syndrome.

Common complications of [disease name] include:

• Compression of vessels in the neck often causes following symptoms :
  • Dyspnea
  • Swollen face
  • Fullness of head on bending forwards
  • Arm swelling
  • Dysphagia
  • Cerebral edema
  • Headache
  • Confusion
  • Coma
• Potential Oncologic emergencies are:
  • Acute airway obstruction
  • Pericardial tamponade
  • Thrombosis of major neck or superior thoracic veins
• Patients with large mediastinal masses are at increased risk of respiratory or cardiac arrest during general anesthesia or heavy sedation.
• Patients who present with cardiorespiratory symptoms or radiographic evidence of tracheal obstruction are at greatest risk of perioperative respiratory morbidity.

• Less common complication includes:
  • Tumor lysis syndrome is caused by massive tumor cell lysis and the release of large amounts of potassium, phosphate, and uric acid into the systemic circulation.
  • Deposition of uric acid and/or calcium phosphate crystals in the renal tubules results in acute renal failure.

• The bone marrow is rarely affected by this type of lymphoma.
• Recurrence or relapse often occurs in organs or tissues outside the lymph nodes (extranodal sites), such as the kidneys or central nervous system.

• Prognosis is generally good after aggressive therapy, which usually combines chemotherapy with mediastinal irradiation. However if relapse occurs , it depends on paucity of molecular level of tumor cells, and their ability to evade immune system.
• Initial studies suggest that a more favorable course may be predicted by one of the following :
  • Low tumor metabolic activity which is determined by decreased total lesion glycolysis (a measure of FDG uptake) on FDG-PET imaging at baseline or after initial therapy. ^[1]
  • Further study is needed to confirm the prognostic value of PET before it can be used to modify initial treatment plans.