A 14-year-old girl presented to the tertiary referral Children's Hospital orthopedic outpatient clinic due to dull pain and periodic wound drainage on the lateral side of her right thigh. Her mother noted two previous surgeries on that area performed at a county hospital. The first one, eight years ago, was performed due to right thigh swelling and fluctuance. These symptoms were initially suspected to be caused by pyomyositis of the vastus lateralis. A small longitudinal incision on the lateral side of the thigh was done and a purulent cyst was evacuated. Samples were sent for microbiological, cytological, and pathological examination. The laboratory reports were not evaluated properly by the treating surgeon, and the girl was discharged from the hospital with recommendations for oral antibiotics to treat pyomyositis. A month after the operation, purulent wound drainage appeared. The child was continued to treated with oral antibiotics and underwent frequent dressing changes, until complete wound closure was achieved. However, 10 months later, swelling, pain and purulent drainage reappeared at the place of the initial incision. The patient underwent repeated surgical incision and evacuation of what was considered to be a recurrent subfascial abscess. After surgery, the patient was instructed to continue with antibiotics and to dressing changes while waiting for wound closure. Unfortunately, her wound was not completely closed. For the next seven years, she suffered from monthly purulent drainage accompanied by moderate swelling and dull thigh pain that was most intense a few days before the appearance of drainage. During that period, there were no complaints about fever or malaise. 
Physical examination and initial considerations 
Seven years after the second surgery, physical examination performed at our institution showed a chronic wound on the lateral right thigh with mild drainage and local erythema. Palpation was slightly painful; however, there was full, painless range of motion of the hip and knee. A swab was taken for microbiological examination and an initial laboratory work-up was done. Microbiology results became positive for Pseudomonas stutzeri, while the laboratory findings were within the normal range. Initial radiographs of the femur were deemed normal. A thigh ultrasound scan revealed a sharply bordered hypoechoic collection between muscles and subcutaneous fat tissue that measured 3X1 cm in size, which was considered to be an abscess. Oral ciprofloxacin 1,000 mg was prescribed for 10 days; however, there was no change in her exam. Therefore, due to clinical presentation and according to previous diagnostic work-up findings, recurrent abscess was suspected. The patient was scheduled for surgical excision followed by continuous intravenous antibiotic therapy. However, while waiting for surgery, she developed intense pain in the right hip. 
Radiological findings 
Hip radiographs revealed a lytic lesion within the greater trochanter with partial reactive sclerosis (Figure 1). Unfortunately, due to the initial symptoms, as well as the site of the previous surgeries and ultrasound findings, surgery was performed without additional imaging studies. 
Surgical technique 
Surgery started with scar tissue excision around the previous wound. However, due to the intraoperative finding of a cutaneous fistula, the skin incision was extended to track the fistula proximally. The fistula was marked with a probe, and a detailed exposure showed a subfascial fistula connected to the enlarged trochanteric bursa (Figure 2a). While operating on the trochanteric bursa, it partially ruptured and whitish liquid tissue, resembling pus was observed. At this point, TB was suspected and the material was taken for acid fast laboratory diagnostics. The fistula and trochanteric bursa were excised completely and sent to pathology (Figure 2b). 
Postoperative findings 
Postoperative intravenous antibiotic therapy was administered for 10 days with 2 g of ceftazidime. The direct microscopic smear examination from the specimen was negative for acid-fast bacilli. The pathology report described tissue changes characteristic for fistula, without specifying the underlying disease. The wound healed uneventfully. There was no longer any local tenderness and the patient was discharged home with recommendations to continue with antibiotic therapy. 
Prior to first postoperative visit, the microbiology culture returned positive for Mycobacterium tuberculosis (M. tuberculosis). The experienced pathologist who reviewed the recent histological findings was notified. The specimen was re-reviewed and corrected identified M. tuberculosis and amended the report to possible TB infection (Figure 3). While discussing these results with the patient's mother, it was found that a close relative that lived with them was TB positive at the time of the index surgery eight years ago. The genotyping results of both M. tuberculosis strains were identical, confirming the likelihood of transmission. In the retrospective analysis of the initial cytology report from eight years ago, it was clearly reported as granulomatous inflammation with necrosis. Therefore, we concluded that the initial presentation with swelling and fluctuance on the right thigh was as a result of TTB. Hip and thigh magnetic resonance imaging (MRI) performed soon after surgery did not show any signs of TB. 
Pulmonology work-up and oral TB therapy 
Due to these findings, a complete pulmonology work-up was indicated. On pulmonary examination, the patient was immunocompetent, afebrile, had non-labored breathing, with normal breath sounds on lung auscultation. Bacille Calmette-Guerin (BCG) vaccination after birth was confirmed by her visible BCG scar. There was no history of previous pulmonary TB, and her chest radiograph showed no signs of pathologic lesions. Culture of sputum samples were negative for M. tuberculosis. Oral TB treatment with four drugs was initiated (isoniazid 300 mg daily; rifampicin 450 mg daily; pyrazinamide 1 g daily; ethambutol 600 mg daily) for two months and continued with two drugs (isoniazid 300 mg daily; rifampicin 450 mg daily) for 10 months. 
The patient completed one year of TB therapy and was followed closely by a pulmonologist and orthopedic surgeon. Twenty months after surgery, she complained about snapping and pain of the right hip, which was successfully managed with physical therapy. At the most recent four-year follow-up, there was no evidence of local recurrence, and the patient returned to all normal activities of daily living. 
An informed consent was obtained from the parents of the patient.