Mycobacterium Tuberculosis Sternal Osteomyelitis Presenting as Anterior Chest Wall Mass

Presentations of tuberculosis are protean and need not be limited to pulmonary disease. We report an unusual case of pediatric sternal tuberculous osteomyelitis presenting as an anterior chest wall mass. Case. A 14-year-old Hispanic male youth was admitted to the hospital with a 2-month history of a progressively enlarging chest wall mass. The patient had resided in Mexico until 1 month before admission. He had been evaluated by several doctors in Mexico during the previous year for a chronic cough, occasional hemoptysis and a 9-kg weight loss. No diagnosis was established. The referring pediatrician in the United States placed a Mantoux skin test. At 72 h the skin test was positive, measuring 40 mm of induration. An older sister was reported to have tuberculosis. The patient was admitted for further evaluation and treatment. The patient was an alert, thin male youth in no acute distress. His height was 137 cm, weight 29 kg (both <3rd percentiles). Vital signs were normal. There was a 1-cm right supraclavicular lymph node. A 3- by 4-cm nontender, firm, right parasternal chest mass was present. Cardiac evaluation revealed a gallop rhythm with no murmur. Decreased breath sounds were heard over the right upper lung. Good air exchange was heard in all other lung fields. There was no hepatosplenomegaly. Neurologic examination was normal. Laboratory data included a white blood cell count of 10 900/mm3, a hematocrit of 38.2%, and platelets of 734 000/mm3. An erythrocyte sedimentation rate was elevated at 76 mm/h. An HIV test was negative. The chest radiograph revealed extensive hilar and mediastinal adenopathy and prominent soft tissue density in the right paratracheal region. Contrast enhanced computed tomography (CT) of the chest demonstrated a soft tissue mass in the anterior mediastinum which eroded the cortex of the manubrium. No evidence of contiguous spread from lung parenchyma or adjacent nodes was present. A small pericardial effusion was also noted. An echocardiogram confirmed a small pericardial effusion and normal cardiac function. The patient was presumed to have pulmonary and extrathoracic tuberculosis. A daily regimen was initiated of isoniazid 10 mg/kg, rifampin 15 mg/kg, pyrazinamide 30 mg/kg and ethambutal 15 mg/kg. Because of tracheal compression and the presence of the pericardial effusion, the patient was treated with prednisone 2 mg/kg/day for 2 weeks followed by a 4-week period of tapering dosages. Sputum cultures and a supraclavicular lymph node biopsy were obtained. Acid-fast bacillus stains were negative from the sputum and tissue samples. The lymph node biopsy reported a benign, reactive lymph node with caseating and necrotizing granulomatous lymphadenitis. Mycobacterium tuberculosis was confirmed by culture from sputum and the lymph node. The organism was susceptible to all first line antituberculous agents. After 2 months the patient was weaned to twice weekly isoniazid and rifampin to complete 1 year of treatment. Follow-up clinic visits and thoracic CT revealed resolution of the pericardial effusion and adenopathy. Discussion. Despite the reduction of total number of case reported to the Centers of Disease Control, tuberculous remains a serious pediatric problem. Certain groups including Hispanics, Native Americans and Asians, especially those born outside the United States, continue to be disproportionally affected.1 The spectrum of pediatric tuberculosis includes asymptomatic primary infection, progressive pulmonary tuberculosis and extrapulmonary disease including cervical adenitis (scrofula), meningitis and osteomyelitis. Skeletal involvement is present in 1.5% of children with tuberculosis.2 Sternal involvement is unusual. Newton et al.3 reported only a single case of chest wall tuberculosis among 74 adult patients with tuberculous osteomyelitis. Adult cases of sternal osteomyelitis are usually associated with a history of immunodeficiency, intravenous drug abuse or trauma.4, 5 Sternal tuberculosis can arise from either direct extension from hilar lymph nodes or hematogenous or lymphatic dissemination. Rana et al.6 reported a case of tuberculosis in a pediatric patient that was secondary to contiguous spread of a parasternal mass. A case report of an infant with a subcutaneous chest wall abscess secondary to hematogenous spread has also been reported by Taşdan et al.7 The exact mechanism of our patient's sternal disease is not clear; the large number of sternal nodes could have served as a nidus for direct extension into the pericardium and manubrium. A component of hematogenous disease could also be present because there was no radiographic evidence of contiguous spread from the nodes or lung parenchyma. CT of the chest is increasingly used to evaluate tuberculosis in children when radiologic findings are normal or inconclusive or when complications of tuberculosis are suspected. A recent review of children with culture-confirmed tuberculous pneumonia found that 20% of the patients had a normal chest radiograph and required CT to visualize the pulmonary involvement. The characteristic CT findings included low attenuation nodes with rim enhancement, calcifications and nodules of bronchogenic spread or miliary nodules.8 In our patient the CT scan was helpful in differentiating the extent of destruction of the sternum and the involvement of the adjacent subcutaneous tissue mass. In addition to tuberculosis the differential diagnosis of a chest wall mass in children includes malignancy, sarcoidosis, actinomycosis and fungal disease. If the diagnosis is not made by other methods, fine needle aspiration or needle biopsy can be useful to confirm the presence of tuberculosis or exclude other conditions. However, aspiration or biopsy may not always confirm the diagnosis. In a recent series of 18 patients with cold abscesses of the chest wall, only 4 had the diagnosis confirmed by needle aspiration. Ultimately all but one patient required surgical debridement caused by either lack of response to medical therapy or absence of a definitive diagnosis. The authors concluded that tuberculous cold abscess of the chest wall is in most cases a surgical entity.9 There is no consensus on the optimal treatment of chest wall tuberculosis. Although some references suggest that medical treatment alone is effective, others believe that aggressive debridement with primary closure as an adjunct to chemotherapy is needed to prevent recurrence or the formation of a chronic fistula.10 Regardless of the need for surgical therapy, appropriate medical treatment must always be given. For extrapulmonary tuberculosis including osteomyelitis, it is recommended that a full year of treatment be given. If the mycobacterial isolate is susceptible to all medications, after 2 months of four drug therapy (typically isoniazid, rifampin, pyrazinamide and ethambutal), isoniazid and rifampin are continued either once daily or twice a week.11 In our patient aspiration was not performed because the diagnosis was made from cultures of sputum and supraclavicular nodes. The patient responded strongly to medical treatment. Surgical resection was avoided in this case. Close follow-up is mandatory in all patients with chest wall tuberculosis to determine whether debridement will ultimately be needed. Acknowledgments. We thank Drs. Lionel Young and Mark Masotto for reviewing the radiologic studies and Dr. Edward Elmendorf for the referral of this patient. Janelle M. Bohl, M.D. Donald Janner, M.D.