Teratoma occupying the left hemithorax.

Background: Teratomas are manifested with a great variety of clinical and radiological features, while sometimes they simply represent incidental findings.

Case Presentation: A rare case of benign teratoma of the dermoid cyst type, in an adult 40-year-old female patient, is reported. The patient had presented recurrent pulmonary infections for the previous 2 months, persistent cough, and progressively aggravating dyspnea. A chest X-ray showed total atelectasis of the left lung, and the thoracic CT-scan revealed a huge mass, containing multiple elements of heterogeneous density, probably originating from the mediastinum, occupying the whole left hemithorax. The mass compressed the vital structures of the mediastinum, great vessels and airways, and a chest MRI was performed to accurately detect the anatomical relations. The patient underwent left thoracotomy and the tumor was totally resected. The size of the tumor was extremely large although no invasion to the vessels or to the airway had occurred. Adherence to the adjacent left pulmonary artery and left main bronchus was present, but without erosion or fistulization. The postoperative course was uneventful, while the histological examination confirmed a teratoma.

Conclusion: A teratoma is a non-homogeneous pathological entity, clinically, radiologically or histologically. It is predominantly diagnosed between the second and fourth decade and the incidence is equal for both sexes. Symptoms are absent in one half of the patients. The case reported is noteworthy as the tumor appeared with total atelectasis of the left lung, and symptoms started 2 months prior to diagnosis. Total removal of the tumor is adequate treatment for this type of teratoma and the prognosis is excellent.