Intramuscular vascular malformations: a rare cause of exertional leg pain and a novel treatment approach with ultrasound-guided doxycycline sclerotherapy

Intramuscular vascular malformations are a rare subset of vascular lesions and present a considerable diagnostic challenge. The majority of vascular lesions are initially misdiagnosed17,20,31 and are often attributed to more common musculoskeletal disorders.14,30,38 Sports medicine practitioners need to be familiar with intramuscular vascular malformations because up to 20% of cases have symptoms of exertional leg pain.20 Exertional leg pain, a common symptom seen by sports medicine practitioners, is defined as exercise-related leg pain distal to the knee and proximal to the talocrural joint. Depending on the study methodology, exertional leg pain has an incidence of 12.8% to 82.4% in athletes.29 Although a comprehensive review of exertional leg pain is beyond the scope of this report, the differential diagnosis is broad and includes musculoskeletal, vascular, and neurologic etiologies (Table 1). Here we present a case of intramuscular venous malformation in the flexor digitorum longus muscle in a 15-year-old female runner with exertional leg pain. Treatment options for intramuscular venous malformations include observation, sclerotherapy, or surgical resection. Although a variety of different sclerosing agents have been described in the literature, to our knowledge, this is the first report of doxycycline sclerotherapy for intramuscular venous malformations.