A Teenage Girl With Painful Walking and a Left Foot Mass

A 12-year-old African American girl presented with a 1-year history of swelling and intermittent pain in her left foot. The swelling and pain had worsened over the past 3 weeks. She reported that prolonged walking increased the pain and swelling, while laying down lead to some improvement. The patient and her mother denied trauma to the left foot. There was no history of fever, nausea, vomiting, abdominal pain, or shortness-of-breath. The rest of her review of systems was unre-markable. Her past medical history was significant for asthma, with no surgical history. The only medication she took was albuterol as needed, and she had no known medication allergies. Family history was significant for diabetes and bipolar disorder. On our physical examination , she was afebrile with stable vital signs. She had an approximately 3 × 3 × 3 cm well-circumscribed, non-tender, fluctuant mass at the dorsum of her left foot, located above the fourth and fifth metatarsals, with no overlying erythema. Her range-of-motion and strength were intact bilaterally. Laboratory work showed a white blood cell count of 7100/mm 3 (47% neutrophils, 42% lymphocytes, and 7% monocytes), hemoglobin 12.6 g/ dL, hematocrit 37.0%, and platelets 279 000/mm 3. C-reactive protein was 3.18 mg/L (normal <9.1), and erythrocyte sedimentation rate was 14 mm/h (normal 9-14). Her foot radiograph showed soft tissue swelling within the fourth and fifth intermetatarsal space, with lucencies in the diaphysis of the fourth and fifth metatar-sals suggesting possible chronic osteomyelitis. Foot ultrasound showed soft tissue mass suggesting phleg-mon and early abscess formation at the site of swelling. No foreign body was noted in either of the examinations. Foot magnetic resonance imaging (MRI) showed subacute/chronic osteomyelitis of the fourth and fifth metatarsals with a 3.3 × 2.4 × 3.7 cm mass consistent with inflammatory pseudotumor and a component of small abscess. There was also extensive cellulitis and myositis involving the dorsum of the midfoot and extending between the fourth and fifth metatarsals to the plantar musculature and fascia. Additionally, the MRI showed a 2.7 cm linear foreign body in between the fourth and fifth metatarsals (Figures 1 and 2). On further questioning, the patient recalled stepping on a toothpick approximately 1.5 years prior to her current presentation. Review of her previous medical records revealed that she had 2 previous emergency department (ED) visits as well. The first visit was shortly after she stepped on the toothpick but nothing could be …