The development of acquired pulmonary arteriovenous communications within pulmonary metastases from an extrathoracic malignancy is a rare phenomenon, but it has potentially serious clinical consequences for the patient. We describe two such patients, both of whom developed intrametastatic pulmonary arteriovenous communications after chemotherapy of the pulmonary metastases, and one of whom required coil embolization for control of symptoms related to the right-to-left shunt. In both cases, computed tomographic angiography was useful for the detection and pre-therapeutic evaluation of the arteriovenous malformations.