Hereditary haemorrhagic telangiectasia (HHT; Osler–Weber–Rendu disease) is an autosomal
dominant vascular disease characterized by nosebleeds, mucocutaneous telangiectases,
visceral arteriovenous malformations (AVM) and a first-degree relative with HHT. Diagnosis
is definite if three or four criteria are present. This case report describes a 19-year-old
male with incidentally detected polycythaemia and an associated soft-tissue opacity
over the left lower lobe on his frontal chest radiogram. He had experienced dyspnoea
on exertion since infancy and clubbing at physical examination. Polycythaemia vera,
chronic obstructive pulmonary disease, sleep apnoea and cyanotic congenital heart
disease were excluded. Chest computed tomography (CT) was initially refused by the
patient, but 3 years later he presented with severe epistaxis. Considering the unvarying
soft tissue mass and erythrocytosis, an HHT-associated pulmonary AVM (PAVM) was eventually
confirmed by chest CT. A pathogenic family-specific ENG c.817-2 A>C mutation was detected
in the patient. The large PAVM was successfully treated using AMPLATZER™ vascular
plug embolization. A combination of the multisystemic nature of his symptoms, the
age-related penetrance of HHT symptoms and insufficient patient compliance delayed
the diagnosis of HHT in this current case
