BALT Lymphoma

BALT lymphoma is an abbreviated term for bronchus-associated lymphoid tissue lymphoma. These neoplasms fall under the broader umbrella of mucosa associated lymphoid tissue (MALT) lymphomas. It is sometimes considered a type of primary pulmonary lymphoma.

Clinical presentation

Up to half of patients can be asymptomatic and tumors are often discovered incidentally.

Pathology

BALT lymphoma represents a low-grade B-lymphocyte lymphoma composed of monotonous small lymphocytes with focal plasmacytoid features. They are composed of subepithelial lymphoid follicles distributed along distal bronchi and bronchioles.

Associations

The tumors can have a number of associations which include :

Radiographic features

CT

Appearances can be quite variable. Described features include:

  • solitary, well-delineated soft-tissue masses - most BALT lymphoma cases
  • less common imaging features include
    • multiple unilateral or bilateral nodules
    • diffuse infiltrates along bronchovascular bundles and interlobular septa
    • extensive lobar infiltrates mimicking consolidation (pneumonia) with air bronchograms or areas of ground-glass attenuation
    • bubble-like radiolucencies
  • hilar and mediastinal lymphadenopathy: not a prominent radiologic finding with nodal involvement present at pathologic analysis in 30% of cases

Treatment and prognosis

Most tend to be slow-growing lesions. The disease is often localized at the time of diagnosis and responds favourably to treatment.