An 87-year-old woman presented to hospital with a progressive, painless pulsating lump in her right forehead. She had fallen and hit her right forehead 1 month prior. She had no neurological deficits. Physical examination revealed a 5 × 5 cm round mass of the right forehead (Fig. 1A). Ultrasonography showed a blood supply into the mass. Magnetic resonance imaging (MRI) revealed a right subcutaneous mass lesion (Fig. 1B, C), and the mass communicated with the frontal branch of the STA on magnetic resonance angiography (MRA) (Fig. 1D). We diagnosed a traumatic pseudoaneurysm of the STA. The patient underwent surgical resection of the pseudoaneurysm under local anesthesia (Fig. 1E) . Histopathological findings confirmed the diagnosis of pseudoaneurysm. The patient’s recovery was uneventful.