Foot Pain In An Ambulatory Adult

HISTORY: A 72-year-old ambulatory adult presents to the clinic with vague right foot pain and swelling. Pain started about 4 weeks prior with no injury or inciting incident. Pain has been constant, but worse with weightbearing and ambulation. Pain is a dull ache, localized to midfoot with occasional radiation to first 3 toes. She received a course of prednisone from her podiatrist w/ minimal relief. Takes Tylenol and tramadol w/ minimal pain relief. Pain is unchanged regardless of footwear. PHYSICAL EXAMINATION: Right Foot: Swelling and warmth of dorsal surface. Diffuse tenderness along the plantar aspect of all metatarsals most prominent on the 3rd and 4th metatarsals. Tenderness between 3rd and 4th metatarsal. Full range of motion. Strength intact in all planes. Sensation preserved throughout. No palpable masses. Dorsalis pedis and tibialis posterior pulse 2+ bilaterally. DIFFERENTIAL DIAGNOSIS: 1. Stress fracture 2. Morton’s neuroma 3. Gout/pseudogout TEST AND RESULTS: Uric acid: 5.5 (ref 2.4-5.7), CRP: 2.6 (ref <0.5). Right foot radiographs: -- Mild dorsal soft tissue edema, no evidence of fracture. MRI right foot w/o contrast: -- Nonspecific fat-containing, soft tissue mass in the plantar midfoot. MRI right foot and ankle w/ and w/o contrast: -- A 4.5 cm (length) by 1.7 cm (width) enhancing, serpiginous mass in plantar soft tissue of midfoot. Dorsal soft tissues edema US right foot: -- Predominately venous malformation with possible posterior tibialis artery involvement on plantar surface of foot FINAL WORKING DIAGNOSIS: Arteriovenous Malformation of Right Foot TREATMENT AND OUTCOMES: 1. Angiogram to assess extent of arterial involvement 2. Plan for sclerotherapy 3. Continue OTC analgesia 4. Wear comfortable and supportive shoes. 5. Follow-up post sclerotherapy for assessment of symptoms