A 19-year-old female presented to the outpatient department with the presence of a single, progressively growing, firm, diffuse swelling over the right preauricular region. There has been progressive trismus for eight months which developed insidiously over the past four months. The patient had been on self-prescribed systemic antibiotics for a week with no clinical improvement. The swelling measured 6 cm x 5 cm in the greatest dimension extending anteroposteriorly from the tragal pointer to a line perpendicular to the lateral canthus of the eye and superoinferiorly from the root of the helix to the inferior border of the mandible [Figure 1a and b] with no cutaneous sinuses.
The throbbing and intermittent pain got aggravated on mastication. The swelling had raised temperature and tenderness on palpation. The cervical lymph nodes were not palpable clinically. Detailed medical history and systemic and intraoral examination were unremarkable. The provisional diagnosis of acute exacerbation of chronic arthritis was made. Orthopantomogram revealed an osteolytic lesion of the right mandibular condyle with loss of corticomedullary architecture, multiple cloaca, and sequestrum. T2W1 magnetic resonance imaging of the head demonstrated a hyperintense area over the right masseteric region extending up to the lateral pterygoid muscle with osteolytic configurational changes of the right mandibular condyle [Figure 2a]. Computed tomogram (CT) of the head revealed an osteolytic lesion in the right condyle measuring 6 cm x 4 cm x 2.3 cm, suggestive of suppurative osteomyelitis [Figure 2b and c]. Raised leukocyte, erythrocyte sedimentation rate, and C-reactive protein count were suggestive of underlying chronic infection.
Based on the above findings, a diagnosis of septic arthritis, TBO condyle, and juvenile idiopathic arthritis was made. Mantoux test showed a negative reaction. Chest radiograph [Figure 3] and high-resolution computed tomography of the thorax were unremarkable. Three sputum specimens and fine-needle aspiration cytology (FNAC) of the swelling were found to be smear and culture negative.
Considering the aetiology to be infectious, the patient was subjected to surgical exploration requiring decortication of bone (sequestrectomy) resulting in medullary destruction and cortical perforation followed by placement of corrugated rubber drain [Figure 4a-e]. Histopathology report of the resected specimen revealed extensive inflammatory infiltrate, focal areas of bone necrosis, caseation granuloma, and lymphocytic infiltration with Langerhans' giant cell. This made us to suspect the presence of tuberculous granuloma which is a consistent finding in a diagnosis of TBO [Figure 4f]. A polymerase chain reaction (PCR) of the curetted material showed positivity for TB bacilli.
The patient was prescribed intravenous antibiotics (amoxicillin with clavulanic acid and metronidazole) for 1 week along with a multidrug antitubercular regimen comprising isoniazid (600 mg), rifampicin (450 mg), pyrazinamide (1500 mg), and ethambutol (1200 mg) for 6 months. The patient was advised of monthly follow-up [Figure 5a and b]. The outcome was satisfactory showing regeneration of bone at nine months, the surgical site healed completely, and CT (head) demonstrated a healthy remnant bone structure [Figure 6a-c].