Extra-intestinal or metastatic Crohn's disease is being recognised inc
reasingly, most commonly in the skin and genitourinary system. Only ve
ry rarely has it been reported in the lung. A 3 year old boy who prese
nted with swollen gums and a persistent abnormality on his chest x ray
is reported. Lung biopsy specimens showed multiple non-caseating epit
helioid granulomas. Subsequent investigation showed the presence of in
testinal Crohn's disease. The evidence for abnormal lung function in C
rohn's disease and the possible pathogenesis of metastatic pulmonary C
rohn's disease are discussed.