Focal aneurysmal dilatation of subchorionic vessels simulating chorioangioma

Subchorionic vascular aneurysms of the placenta are rare lesions and may present confusion with chorioangioma or focal mesenchymal dysplasia on sonography. To our knowledge, the findings of placental aneurysms have not been reported in the ultrasound literature. We present a case with detailed sonographic evaluation, including spectral and color Doppler and pathological analysis, that was mistaken for chorioangioma prenatally. Knowledge of this benign entity may allow the sonologist to recommend conservative management in similar cases.