Immunohistochemical study with antibody to glycoprotein GCDFP-15 for metastatic lung cancer from breast cancer.

Even when gross pathologic specimens are available, evaluation is always complicated due to the difficulty in distinguishing the pathologic diagnosis of an adenocarcinoma as a pulmonary metastasis of the breast or lung. In this paper, we describe the usefulness of a preoperative immunohistochemical study using gross cystic disease fluid protein-15 (GCDFP-15). A 50-year-old woman, who had undergone a right radical mastectomy due to an infiltrating ductal carcinoma 4 years previously, was admitted because of an abnormal shadow on chest roentgenography. A chest CT scan showed a nodule 20 mm in diameter with an irregular margin and vascular involvement in the S3 region of the right lung. Though the specimen from a percutaneous CT guided needle biopsy revealed characteristic pathologic findings of a primary lung adenocarcinoma under H.E. stain, which was recommended for lobar resection, we re-examined that specimen immunohistochemically, which disclosed that the tumor cells were negative for the antibody to pulmonary surfactant apoprotein and were positive for GCDFP-15 antibody. Therefore, the diagnosis of a metastatic breast carcinoma in the lung was established. Upon her request, a wedge resection of the right upper lobe including the tumor was performed under video-assisted thoracoscopic surgery (VATS). Her postoperative course was uneventful.