Presentation
Incidental finding of right middle lobe mass on CXR
Patient Data
In the right middle lobe a pulmonary arteriovenous malformation is demonstrated the nidus measuring 20 x 20 x 25 mm. It is fed by a single enlarged branch from the pulmonary artery and drains, via the lower pulmonary vein, into the left atrium. It appears to be an isolated abnormality, with the remainder of the lungs, pleura and mediastinum appearing normal. Limited views through the upper portions of the abdominal solid viscera appear unremarkable.
Conclusion: Right middle lobe arteriovenous malformation.
Case Discussion
Pulmonary AVM's may occur in isolation or be a manifestation of Osler's disease where innumerable AVM's are present in both lungs.
Small solitary lesions are often asymptomatic, larger lesions may present with some respiratory symptoms secondary to the shunt.
Paradoxical embolism may also be the first manifestation in some situations