[Pulmonary Adenocarcinoma in Situ with Positive Findings in Pleural Lavage Cytology]

We report a rare case of positive findings in pleural lavage cytology(PLC) in the patient with pulmonary adenocarcinoma in situ (AIS). A 78-year-old woman was presented with a 30 mm pure groundglass nodule (GGN) in the left upper lobe on chest computed tomography (CT). After 2 years follow- up, thoracoscopic surgery was performed to resect the nodule. PLC was performed before pulmonary resection. Histopathological diagnosis was 25 mm AIS. However, PLC showed positive findings of malignant cells. CT examination at 1 year and 6 months postoperatively showed pleural dissemination findings and the patient died of lung cancer at 3 years and 2 months postoperatively. PLC's contribution to TNM staging has not yet been clarified. The positive findings in PLC and large size of pure GGN were considered likely to be poor prognostic indicators.