Breast panniculitis with vasculitis on ultrasound. a. A heterogeneously hypoechoic nodule within the right breast measures 1.35 cm × 0.39 cm in size (arrows). b. A faint echogenic interface (short arrows) and partially instinct margin (long arrows) of the nodule are present. c. Normal skin (short arrow) and skin thickening (long arrow) over the nodule are observed. d. Additional hypoechoic satellite nodules (short arrows) are visualized. e. Blood flow signals increase in and around the nodule on color Doppler (arrow). f. A sono-guided biopsy of the nodule with an 18-gauge core biopsy needle (arrow) is performed.