Symptomatic plantar fibroma with a unique sonographic appearance

We present a case of a solitary plantar fibroma with unique sonographic features with MRI and pathologic correlation. A 25-year-old woman presented with a left foot mass that interfered with her gait. Sonography demonstrated a well-circumscribed, 32 mm × 27 mm × 14 mm subcutaneous mass with heterogeneous echogenicity. Unique sonographic characteristics included posterior acoustic enhancement, cystic components, and mild intratumoral hypervascularity. MRI confirmed the sonographic findings. Surgical excision was performed without complication. A pathologic diagnosis of fibroma with myxoid degeneration and cyst formation was made.