Aims: Pulmonary sclerosing pneumocytoma is a rare benign neoplastic tumour. It is often discovered incidentally in chest X-ray or chest CT scan performed for others reasons. We present here a case of pulmonary sclerosing pneumocytoma and discuss the clinical, histopathological features and treatment of this tumour in light of the data of the literature. Methods and Results:We report the case of pulmonary sclerosing pneumocytoma found in 66-year-old woman on chest CT scan performed for staging of a breast cancer. The patient underwent a left lower lobectomy and ipsilateral médiastinal lymph node dissection because frozen section examination suggested papillary adenocarcinoma. Conclusion:Most occurrences of pulmonary sclerosing pneumocytoma is often discovered incidentally. It is a rare benign tumour that frozen section examination is unable to diagnosis them in 25 to 56% of cases. The prognosis after surgical resection is excellent.