Calvarial venous malformation highlighted by the flow-reflux phenomenon on ultrasound.

A case is reported of a woman presenting with a firm, tender right frontal lump. Ultrasound showed a small, irregular subgaleal mass with tiny bone surface perforations. Color Doppler ultrasound demonstrated compression-decompression induced alternating flow signals, indicating flow and reflux through the bone lesion. CT revealed an expansile osteolytic frontal lesion with a honeycomb pattern, consistent with an intraosseous venous malformation, which was confirmed histologically. The added value of compression-decompression color Doppler ultrasound in low‑flow calvarial vascular malformations is illustrated. Teaching point: Compression-decompression color Doppler ultrasound can reveal flow-reflux in low‑flow intraosseous venous malformations, contributing to the diagnosis.