[Lung Abscess Diagnosed as Adenocarcinoma by Needle Biopsy;Report of a Case].

We report a case of lung abscess misdiagnosed as adenocarcinoma based on cytologic findings of the sample obtained from needle biopsy. A 45-year-old man consulted our hospital because of fever, wet cough and an abnormal shadow on a chest X-ray film. A chest computed tomography revealed gradually enlarging pulmonary mass in the left S6 infiltrating the S5. A diagnosis of lung cancer was suspected and surgery was performed. Pathological findings of the specimen showed atypical cells with a large nucleus and a gross papillary neoplasm by needle biopsy. The patient underwent left lower lobectomy and partial resection of upper lobe with standard nodal dissection. The final diagnosis was a lung abscess with pneumonia without evidence of malignancy. When an indeterminate pulmonary tumor must be diagnosed during an operation, we should perform partial resection if possible.