Primary tuberculous osteomyelitis of the mandible in a 3-year-old child

A 3-year-old girl child presented with swelling in her right lower jaw that had started 5 days previously. History revealed the child being non-immunised. Initial-evaluation revealed proptosis and bony hard swelling over the right body of the mandible. Radiological evaluation including a CT scan indicated expansile osteolytic lesion involving the body-ramus with onion-peel periosteal reaction suggesting osteomyelitis/malignancy. Blood investigations showed raised erythrocyte sedimentation rate and eosinophilia. Family screening for tuberculosis (TB) revealed that the patient, her father and siblings were PPD positive though chest screening and sputum examinations were negative in all of them. Lesion biopsy showed acute/chronic osteomyelitis with eosinophilia, tilting diagnosis towards eosinophilic granuloma/Hand-Schuller-Christian disease. Further investigations for diabetes insipidus, histiocytosis-X, skull-pelvic-femur radiographs, abdominal ultrasonography, ophthalmic consultation and PCR-TB test were negative. Histology, radiography, purified protein derivative (PPD)-positive result and history led to the diagnosis of primary TB of the mandible. Complete resolution occurred following antitubercular therapy. The case report emphasises that diagnosis of TB can sometimes be based on circumstantial evidence and positive response to antitubercular therapy even in view of a negative PCR result.