Unexpected rapid growth of estrogen receptor positive lung cancer during pregnancy.

We report a case with lung cancer during pregnancy, which has a very poor prognosis.A 34-year old female at 30 weeks of pregnancy came to us with a cough and right lower chest pain. Chest computed tomography revealed a mass in the right lower lung lobe and the diagnosis of adenocarcinoma cT2aN1M0 was made. We performed a right sleeve pneumonectomy, as the tumor had progressed to the right main bronchus near carina. Histological sections of the specimens revealed a poorly differentiated adenocarcinoma that infiltrated surrounding structures. The pathological stage of lung cancer was T4N2M0 stage IIIB. Immunohistochemistry findings for estrogen receptor β were positive in the nuclei of the adenocarcinoma. She had a rapid recurrence in spite of chemotherapy, and she died 7.5 months after operation. The positive estrogen receptor and hormonal condition during pregnancy might promote cancer and result in her poor prognosis.