OBJECTIVETo study the pathological characteristics of severe acute respiratory syndrome (SARS) and its relationship to clinical manifestation.

METHODSTissue specimens from 3 autopsy cases of diagnosed SARS were studied under microscopy and the clinical data were reviewed.

RESULTSThe typical pathological changes of lungs were diffuse hemorrhage on surface. A mixture features of serous, fibrinous and hemorrhagic inflammation were seen in most pulmonary alveoli with engorgement of capillary and there were microthrombosis in some capillary. Pulmonary alveoli became thick with interstitial mononuclear inflammatory infiltration, diffused alveoli damage, desquamation of pneumocytes and hyaline-membrane formation. Fibrinoid materials and erythrocytes could be found in alveolar spaces. There were thrombo-embolisms in some bronchial artery. Meanwhile, haemorrhagic necrosis was showed in lymph nodes and spleen with attenuation of lymphocytes. Other atypical pathological changes, such as hydropic degeneration, fatty degeneration, interstitial cell proliferation and some lesions observed in liver, heart, kidney, pancreas may have existed before the hospitalization.

CONCLUSIONSevere damages of pulmonary and immunological system damage are responsible for clinical features of SARS and may lead to death of patients.