Utility of thyroid transcription factor-1 expression in the differential diagnosis of metastatic adenocarcinoma of serous effusion specimens prepared using the cell transfer technique

Background/Purpose: Pulmonary adenocarcinoma is a common malignancy of the pleural cavity. The cell transfer technique can be used to create multiple slides from a single smear. The goal of this study was to investigate the pulmonary origin of metastatic adenocarcinoma by evaluating the immunocytochemical reactivity to thyroid transcription factor-1 (TTF-1) of slides of serous effusion specimens prepared by the cell transfer technique. Methods: In 2001, a total of 76 archived serous effusion specimens containing adenocarcinoma from patients were used in this study. The primary site of metastatic adenocarcinoma was determined by a review of the medical records. The cell transfer technique was used to create multiple slides from a single Papanicolaou-stained smear. if more than 10% of the target cells reacted with perceptible intensity, nuclear staining was considered to indicate a positive TTF-1 result. Results: Positive rates of TTF-1 for body fluids collected from patients with lung, stomach, ovarian, breast, colorectal and liver carcinomas were 41/50, 0/11, 0/6, 0/5, 0/2 and 0/1, respectively. Lung adenocarcinoma showed TTF-1 positivity in 82% of specimens, and all other adenocarcinomas had negative TTF-1 staining results. Conclusion: This study demonstrated that TTF-1 immunostaining in serous effusion specimens prepared using the cell transfer technique is a sensitive and highly specific marker for metastatic lung adenocarcinoma. ? 2006 Elsevier & Formosan Medical Association.