A 55-year-old woman presented to the emergency department with a sharp pricking sensation when lying on her back. Radiography and thoracic computed tomography showed a calcified mass 6 × 6 cm in dimension in the right anterolateral mediastinum (fig 1A,B). The mass was excised with a right anterior thoracotomy. Pathological examination reported this to be a mature cystic teratoma. The patient was admitted for surgery.

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Figure 1 (A) Posteroanterior image showing a smooth and calcified contours mass in the right hilar region in the left hemithorax. (B) The thoracic computed tomography showing a calcified mass 6×6 cm in dimension in the right anterolateral mediastinum.

Most mediastinal teratomas are benign. These tumours tend to be diagnosed incidentally by thoracic imaging. When symptoms occur, they may be due to compression, invasion of the adjacent intrathoracic structures, or various cosyndromes. The most frequent symptom is chest pain. A mass found on thoracic imaging to have smooth contours and calcified areas in the anterior mediastinum is very likely a teratoma. Total surgical excision is indicated for any malignant or benign well-demarcated mass in any part of the mediastinum.1