Vascular leiomyoma presenting as medial joint line pain of the knee.

Vascular leiomyoma or angioleiomyoma is a rare benign solitary smooth muscle tumor that occurs mostly in the extremities. Most of these tumors are composed of venous vessels, but in some reports small arteries have been detected in the tumors.We present a rare case of a 60-year-old man with a subcutaneous vascular leiomyoma of the right knee. Clinical findings, ultrasound (US), magnetic resonance (MR), and histopathologic features are reported, and the literature is reviewed. The knowledge of specific imaging findings allows to include vascular leiomyoma in the differential diagnosis of lower extremity subcutaneous masses and to achieve an early accurate diagnosis.