FAMILIAL HEMOPHAGOCYTIC LYMPHOHISTIOCYTOSIS - A REPORT OF 3 CASES WITH UNUSUAL LUNG INVOLVEMENT

Three cases of familial haemophagocytic lymphohistiocytosis are presen ted with lung infiltration by haemophagocytic histiocytes. In all pati ents the diagnosis was based on hepatosplenomegaly, thrombocytopenia a nd anaemia, abnormal increase in triglycerides, ferritin and LDH, hypo fibrinogenaemia and lymphohistiocytosis with haemophagocytosis in bone marrow. Two patients died of respiratory failure due to interstitial pneumonia. In these two patients the pneumonia was obscured and misint erpreted by the pathologists. A careful re-examination revealed lympho histiocytosis and haemophagocytic cells within the lung parenchyma. Th e third patient showed alveolar wall infiltration by haemophagocytic h istiocytes and lymphocytes. In early childhood acute or recurrent inte rstitial pneumonia should prompt a search for haemophagocytic histiocy tes, and familial haemophagocytic lymphohistiocytosis should by includ ed in the differential diagnosis.