A 12-year-old boy presented with complaints of fever and cough occurring on and off for 2 years. The child was diagnosed as empyema by the local physician and an intercostal drain was inserted which drained minimal foul smelling fluid. The drain was apparently retained for 3 months in view of persistent discharge and child was treated with anti-tubercular therapy for 9 months. For last 6 months, he complained of progressive dyspnoea, not associated with any postural variations. He had a sinus in the chest which was persistently draining 5-10 ml of foul smelling fluid daily. He had a history of significant weight loss and decreased appetite for 6 months. There was no history of contact with tuberculosis in the family. On examination he was found to be wasted with severe acute malnutrition. General physical examination revealed severe pallor with grade III clubbing. Respiratory system examination revealed a bulging chest on the right side with decreased movements. The same areas were found to be dull on percussion. Bronchial breathing was present in the right infraclavicular and interscapular regions. All the other systems were within normal limits. Chest X ray (Fig. 1) showed a homogenous opacity on the right side with a fluid level, with clear costophrenic angles. Calcification was noted in the right 6th intercostal spaces with crowding of ribs in the upper zones. USG chest showed evidence of minimal (1.4mm) loculated collection in right posterior basal region. CT chest (Fig. 2) done revealed a well circumscribed peripherally enhancing multiloculated cystic fluid and a soft tissue density lesion with fat components, well defined multiple calcified tooth like structures and bone pieces. There were associated patchy sub-segmental non homogenous opacities in apical and posterior segment of right upper lobe. Multiple small non-calcified, non-necrotic right paratracheal, pre-tracheal and subcarinal lymphadenopathy were noted. The cultures from the sinus tract grew pseudomonas aeruginosa and serratia marcescens sensitive to ceftazidime and amikacin. The patient thus received a course of antibiotics for 2 weeks. The fever subsequently subsided. Serum alpha protein levels were within normal limits.
 A right sided thoracotomy was done and tumour was excised en-bloc. A white-gray colored, well circumscribed, and thick capsulated mass was removed. No communication between the bronchi and the mass were noted. The teratoma was found to be originating from the posterior mediastinum (Fig. 3). A tube thoracostomy was left, the collapsed right lung was re-expanded, and the patient was extubated. Postoperative course remained uneventful. Gross pathological examination showed a 10x6x3 cm mass with 2 skin covered nodules with grey yellow (fatty) and bony hard areas within focally cystic areas on cut section. Histopathological examination showed areas of fat, bone, teeth and lung tissue with normal skin tissue on the covering and with occasional neural tissue present, suggestive of a mature teratoma.