Pulmonary arteriovenous malformations (PAVMs), particularly where feeding artery/arteries to PAVMs ≥ 3 mm can be treated with embolization. The treatment for hypoxemia resulting from multiple small or diffuse PAVMs remains unclear.We report a girl aged 5 years and 10 months presented with cyanosis and decreased activity after exercise (83–85% of pulse oxygen saturation, SpO2). She had 1 skin lesion on her face and 1 suspected hemangioma on her left upper extremity at birth and that gradually disappeared spontaneously. Physical examination revealed clubbed fingers, and abundant vascular networks on her back. Contrast-enhanced lung CT (slice thickness:1.25 mm) with vascular three-dimensional reconstruction and abdominal CT revealed increased bronchovascular bundles, increased diameter of the pulmonary artery and ascending aorta, and intrahepatic portosystemic venous shunts due to patent ductus venosus. Echocardiography revealed increased diameter of aortic and pulmonary artery. Transthoracic contrast echocardiography was highly positive (bubble appearing in the left ventricle after 5 cardiac cycles). Abdominal doppler ultrasound revealed hepatic-portal venous shunt. Magnetic resonance imaging, artery and vein of the brain revealed multiple malformations of venous sinuses. The patient received sirolimus for 2 years and 4 months. Her condition improved significantly. SpO2gradually increased to 98%. Her finger clubbing gradually normalized.Our report implicates sirolimus might be a potential treatment option in persistent hypoxemia mainly due to intrapulmonary right-to-left shunt even small multiple or diffusive PAVMs in pediatric patients with multiple cutaneous and visceral vascular anomalies.