In this series, the commonest aetiology was tuberculosis (24 cases), Hodgkin's disease (21 cases), sarcoidosis (14 cases) and Q fever (14 cases). Some morphological features such as number and size of granulomas seemed useful for aetiological diagnosis. A granuloma with a central fat vacuole surrounded by fibrinoid material was in favour of Q fever. A dense mononuclear sinusoidal infiltration was associated with granulomas in MNI or CMV infections. 19 cases were cryptogenetic.