Primary acinic cell carcinoma (ACC) of the lung is extremely rare. The World Health Organization tumor classification defines ACC as "a malignant epithelial neoplasm that demonstrates some cytological differentiation towards (serous) acinar cells". It is considered to be a low-grade malignant tumor. Since the first case described by Fechner in 1972, less than 30 cases have been reported in the literature. The rarity of this tumor may leads it to be confused with other primary lung tumors and incorrectly diagnosed. We reported a female patient with primary ACC of the lung with mediastinum deviation at age of 27 years received a right pneumonectomy. She was followed up for 12 months postoperatively and remains well.