Primary Pulmonary Lymphoma


(aka Mucosa-Associated Lymphoid Tissue, MALT-Associated Lymphoma)

Epidemiology: accounts for <5% of all extranodal NHL


Pathogenesis


Pathology


Diagnosis

OLB: usually required (but diagnosis is often difficult)
-Identification of the cells as monoclonal is necessary to rule out benign reactive lymphoid proliferation
-Immunohistochemical stains: may aid in identify B-cell origin

CXR/Chest CT Patterns:
1) “Bronchovascular-Lymphangitic” Pattern: presents as diffuse reticulonodular infiltrates
2) “Alveolar” Pattern: may be segmental or lobar, resembles pneumonia
3) “Nodular” Pattern (small and large nodules): most common pattern
-Lower-lobe predominance
-Nodules may cross fissures
-Nodules may have air bronchograms
-Nodules may cavitate
4) Pleural Effusion:

PET Scan: positive
-Useful to follow after therapy (as scan should revert to PET-negative): recurrence may be manifested by return to being PET-positive


Clinical

Signs:
-Lymphadenopathy usually absent

Complications:
-Transformation to high-grade NHL (in <50% of cases): usually portends poor prognosis


Treatment

Symptomatic: surgical resection is preferred for resectable disease
-XRT: for unresectable or incompletely resected disease
-Chemo: for extensive disease only
-Steroids: have been used


Prognosis