Right Distal Thigh Pain - Water Polo

Abstract

HISTORY: A 15 year old male experienced spontaneous onset of distal lateral thigh pain during his water polo season without preceding event. Symptoms, including an ache and hypersensitivity, responded to activity modification but recurred immediately upon activity resumption, with knee extension even against gravity. He noted no mechanical symptoms, swelling or discoloration. Patient had been receiving physical therapy for presumed distal quadriceps tendinosis but was soon unable to tolerate even topical treatments to the region. PHYSICAL EXAMINATION: Exam revealed tenderness localized to the superior pole of the patella and the vastus lateralis-retinacular interface without nodularity. No knee effusion was present, and all provocative maneuvers of the knee were negative. Give-way weakness of the right quadriceps was present as was skin hypersensitivity. DIFFERENTIAL DIAGNOSIS: 1. Proliferative synovial disorder 2. Vascular malformation 3. Chronic musculotendinous strain of the vastus lateralis-retinacular region 4. Malignancy TEST AND RESULTS: Femur radiographs were negative but contrast MRI of the distal thigh revealed a T2 hyperintense lobulated mass deep to the vastus lateralis and quadriceps tendon, separate from the suprapatellar recess. CT guided biopsy showed benign fibrovascular tissue consistent with an arteriovenous malformation (AVM). FINAL WORKING DIAGNOSIS: Slow flow arteriovenous malformation TREATMENT AND OUTCOMES: The patient underwent percutaneous sclerotherapy with 2cc of absolute alcohol. He reported complete resolution of pain within 1-2 weeks and returned to all previous competitive activity.Figure