Abstract
Background : It is very rare that malignant cells of extrauterine cancer, especially primary lung cancer, metastasize to the uterine endometrium.
Case : A 70-year-old postmenopausal female was referred to our hospital due to abnormal Pap screening result of the uterine cervix. The patient was diagnosed as having primary lung cancer 18 months previously and had been undergoing chemotherapy. The result of the cervical Pap smear retested was normal. However, the endometrial cytology showed tumor diathesis and many adenocarcinoma cell clusters, but there were no abnormal findings on endometrial curettage for histological examination, magnetic resonance imaging, and hysteroscopy. We then performed some histological and immunohistochemical examinations to clarify the origin of the endometrial malignant cells using the cell block technique. The specimens stained positively for thyroid transcription factor-1 and surfactant proteins A, and negatively for estrogen receptor and progesterone receptor. The results revealed that the endometrial abnormal cells originated from the lung cancer.
Conclusion : Immunohistochemistry tests on paraffin cell block sections are an useful procedure to make a correct diagnosis, in the cases where sufficient histological specimens cannot be obtained.
