This is a case of left lingular pulmonary arteriovenous malformation ( simple type) evidenced by single segmental artery feeding the malformation.
The patient initially came for HRCT thorax to look for interstitial lung disease in view of underlying rheumatoid arthritis. HRCT showed indeterminate UIP pattern and incidental finding of PAVM which was further evaluated by CTPA.
PAVMs are rare vascular abnormalities consisting of fistulous connections between dilated pulmonary arteries and dilated pulmonary veins resulting in a right-to-left shunt 1, bypassing the normal pulmonary capillary bed.
The most common association is hereditary hemorrhage telangiectasis.
Contrast-enhanced CT thorax or transthoracic contrast echocardiography (TTCE) are useful for further evaluation 1.