primary pulmonary lymphoma
Primary pulmonary lymphomas refer to clonal lymphoid proliferation affecting the lungs without any detectable extrapulmonary involvement. It is much rarer than secondary pulmonary lymphoma and is most frequently represented by lymphoma of B-cell lineage - often marginal zone B-cell lymphoma of mucosa-associated lymphoid tissue (MALT) type.
Primary pulmonary lymphoma is a very rare entity and is thought to represent only 3-4% of extranodal non-Hodgkin lymphoma, <1% of all non-Hodgkin lymphoma, and 0.5-1% of all primary pulmonary malignancies .
The diagnosis of primary pulmonary lymphoma requires the following criteria (as of December 2012) :
- involvement of lung, bronchus, or both, without evidence of mediastinal lymphadenopathy or mass on a chest radiograph
- no previous extrathoracic lymphoma
- no evidence of extrathoracic lymphoma or lymphatic leukemia at the time of diagnosis
- no extrathoracic disease outside the thorax for least three months following the initial diagnosis within the lung
When the lung is the principal site of lymphoma, the definition also includes:
- multifocal mucosa-associated lymphoid tissue (MALT) non-Hodgkin lymphoma
- pulmonary involvement with satellite nodes (hilar or mediastinal)
- multiorgan involvement by lymphomatoid granulomatosis, the clonal nature of which is controversial
Treatment and prognosis
This entity of lymphoma is thought to carry a comparatively good prognosis .