Intrathoracic involvement is common in both Hodgkin's disease (HD) and
non-Hodgkin's lymphoma (NHL). The most common manifestation is medias
tinal lymphadenopathy. In HD, nodal involvement is by contiguity and u
sually involves the superior mediastinum, while the findings in NHL ar
e more variable. Pulmonary parenchymal disease occurs in 38% of HD and
24% of NHL. In untreated HD, parenchymal involvement is invariably as
sociated with mediastinal lymphadenopathy and often with widespread di
sease. Three distinct radiological patterns of pulmonary lymphoma are
recognised: nodular, bronchovascular-lymphangitic and pneumonic-alveol
ar. Rarely lymphoma may be endobronchial. Pleural effusion occurs in 1
6% of lymphoma patients and is usually associated with disease elsewhe
re. It is frequently caused by lymphatic obstruction but may be due to
direct pleural involvement by tumour. Chylothorax may occur in NHL bu
t is unusual in HD. Diagnosis of intrathoracic lymphoma is by transbro
nchial or transthoracic biopsy or by needle aspiration of tissue or pl
eural fluid. The addition of immunostaining improves the diagnostic yi
eld in equivocal cases. Treatment and prognosis vary depending on cell
-type, location and extent of disease.