A 14-YEAR-OLD girl had severe, sharp mid-back pain for 3 weeks and nontender, gradually enlarging left chest wall swelling for 2 weeks. It was unrelieved by change of position. One month before symptoms started, she had fallen, striking her left chest. No bruise remained and the tenderness subsided; however, 2 weeks later, swelling began in the area of injury. She had lost 10 pounds over the last 2 months while dieting. She had no fever, cough, chills, sweats, joint pain, or rash. Last year, she lost a filling from a right upper molar, but otherwise, her last dental care was 6 years ago. She was receiving 325 mg of ferrous sulfate per day for iron deficiency anemia diagnosed 1 month earlier. Findings from physical examination revealed an obese female (height, 139.7 cm; weight, 83.3 kg). Her temperature was 38.5°C; pulse, 120 beats per minute; respirations, 20 breaths per minute; and blood pressure, 122/88 mm Hg. Spinal examination showed scoliosis but no vertebral or costal tenderness. A 4-cm mass was palpated over the left rib cage at the anterior axillary line in the 10th interspace. This mass was ovoid, nontender, soft, and cool to the touch without erythema. A large cavity was present in the upper left molar.
Laboratory results included hemoglobin, 5.9 g/dL; hematocrit, 21.2%; mean corpuscular volume, 67.4 fL; red cell distribution width, 18.6%; reticulocyte count, 2.6%; prothrombin time, 16 seconds; and partial thromboplastin time, 33 seconds. Chest radiograph showed scoliosis of the lower thoracic and upper lumbar spine, cardiomegaly, a retrocardiac consolidation, and left pleural effusion. Fine-needle aspiration of the chest wall mass yielded 20 mL of purulent material; the chest wall abscess was incised and drained. Serum iron was 10 µg/dL; total iron binding capacity, 159 µg/dL; and ferritin, 397.2 ng/mL. Erythrocytes were hypochromic and microcytic, and the neutrophils had toxic granules. Erythrocyte sedimentation rate was greater than 140 mm/h. The rheumatoid factor was positive, and IgG and IgM were increased to 2234 mg/dL and 627 mg/dL, respectively.
Treatment was started with antimicrobials, analgesics for back pain, and vitamin K injections for prolonged prothrombin time. The prothrombin time remained prolonged despite vitamin K administration and infusion of fresh frozen plasma. Anticardiolipin antibody was positive. Routine cultures from the abscess grew no organisms. The tuberculin skin test result was negative, and an anergy panel was positive. Computed tomography (CT) of the chest and abdomen (Figure 1), lateral radiography (Figure 2), and then magnetic resonance imaging scan of the spine were performed. A CT-guided biopsy of the paraspinal mass was performed. Pathologic findings are shown in Figure 3 and Figure 4.