Abstract Introduction Mediastinal teratomas are rare, comprising about 15% of mediastinal germ cell tumors and 6% of all primary mediastinal neoplasms. 1-2. They are less common than thymomas, lymphomas, and neurogenic tumors. Accurate diagnosis often requires a combination of imaging studies and histopathological examination.3 Case A 55-year-old female, lifelong never-smoker with no significant medical history, was incidentally found to have a large left lung mass on a CT scan of the abdomen and pelvis performed during the evaluation of microscopic hematuria. A subsequent CT of the thorax identified a well-defined, solid, heterogeneous mass in the left middle mediastinum, measuring 7.8 × 10 × 10.4 cm, with lateralization to the left hilum, raising suspicion for malignancy. Two CT-guided biopsies were attempted, but both were nondiagnostic. A bronchoscopic approach was not attempted due to the tumor’s size , extent and heterogeneous composition, and instead a surgical approach was preferred. She subsequently underwent a left posterolateral thoracotomy with complete surgical excision of the mass, with no postoperative complications. Histopathological examination confirmed the diagnosis of a mature cystic teratoma. Discussion Patients with mediastinal mature cystic teratomas may be asymptomatic or present with symptoms such as chest pain, cough, dyspnea, or superior vena cava syndrome due to compression of adjacent structures. In rare cases, they may rupture into nearby structures like the lung, bronchus, pleural space, or pericardium, leading to further complications. Fortunately, in our patient, the tumor was discovered early, before any such complications arose, and she had a smooth postoperative recovery.Imaging modalities such as CT and MRI play a critical role in the initial evaluation. The tumor’s large size and heterogeneous appearance on CT raised concern for malignancy, necessitating further tissue sampling. However, two separate CT-guided biopsies were nondiagnostic, highlighting a common challenge in diagnosing mediastinal teratomas due to their varying tissue components, including cystic, fatty, and calcified elements. However, definitive diagnosis remains dependent on histopathological confirmation following surgical excision. Complete excision of a mediastinal teratoma is generally curative, with recurrence being rare. The surgical approach may vary based on the tumor’s size, location, and accessibility. Options include median sternotomy, video-assisted thoracoscopic surgery (VATS) or open thoracotomy. Histologically, mature cystic teratomas contain well-differentiated tissues derived from all three germ layers—ectoderm, mesoderm, and endoderm. Common components include skin, hair, sebaceous material, and, in some cases, teeth or bone. The presence of these mature tissues confirms the diagnosis and distinguishes these tumors from other mediastinal masses.5-6 This abstract is funded by: none
Naik et al. (Fri,) studied this question.