Background: The Rendu-Osler-Weber syndrome, also known as hereditary haemorrhagic telangiectasia (HHT) is a rare (1 in 10 000) hereditary autosomal dominant disorder caused by the mutation in one of two different genes on chromosome 9 or 12. The syndrome is characterized by dermal and mucosal telangiectases and by arteriovenous fi stulas that are mainly present in the lungs and the central nervous system (CNS), and less commonly in the liver. The major cause of morbidity and mortality due to this disorder is the presence of multiorgan arteriovenous malformations and the associated haemorrhages that may accompany them. In the Rendu-Osler-Weber disease, the bleedings are caused by degenerative changes in the capillaries lacking the elastic muscular-fi brous layer and hyaline lesions.
Case Report: A 19-year-old 5-month pregnant patient was admitted to the Department of Pneumonology because of a pain in the right chest that caused diffi culties in breathing. The physical examination and chest X-ray revealed the presence of fl uid in the right pleural cavity; 500 ml of bloody fl uid was released. The history revealed the Rendu-Osler-Weber syndrome and the arteriovenous fi stula in the right lung diagnosed at the Children Health Centre in 1997. After the consultation with gynaecologists, surgeons and radiologists, multislice computed tomography of the lungs was performed. The examination showed a large arteriovenous fistula with bleeding to the pleural cavity. The patient was decided to be treated by pulmonary embolization. The selective embolization of the artery feeding the vascular malformation resulted in the complete, effective closure of the fi stula.
Conclusions: The presence of one disease (the Rendu-Osler-Weber syndrome and PVAMs) obliges to search for another disorder. The follow-up examinations should be performed in patients with the Rendu-Osler-Weber syndrome every 5 years or more often (e.g. in pregnancy or before planned pregnancy). Due to frequent complications in Rendu-Osler-Weber syndrome patients in pregnancy, CT and angiography should be performed, and embolization should be considered, if necessary. At present embolization is regarded the gold standard of PVAM treatment.

Keywords: Rendu-Osler-Weber Syndrome, PAVM, embolization