Intrapulmonary cystic teratoma mimicking malignant pulmonary neoplasm.

Benign cystic teratoma of lung is an extremely rare tumour, which was first described in literature by Mohr in 1839. Intrapulmonary teratoma is thought to be a derivative of the third endo-dermal pharyngeal pouch, which is an anlage of the thymus. The authors present a rare case of mature cystic teratoma in a young male involving the right upper lobe of the lung. Diagnosis is often missed and patients are treated for various infectious conditions. Treatment is complete resection for both benign and malignant teratomas and carries excellent prognosis. Benign cystic teratoma, if not excised may cause grave complications like life-threatening haemoptysis or malignant transformation with metastatic disease.