[Clinical analysis of solitary pulmonary nodule measuring less than 10 mm]

Lung cancer is a malignant disease with high incidence and mortality, and its prognosis is to large degree determined by early diagnosis and treatment. X-ray chest film and computed tomography (CT) are important means to discover and diagnose lung cancer. But it is difficult to diagnose single pulmonary nodules (SPN) measuring less than 30 mm, especially for those less than 10 mm. This study was to analyze the CT imaging features of SPN measuring less than 10 mm.

The clinical and radiologic features of 102 cases of pathologically diagnosed SPN measuring less than 10 mm with CT reports were analyzed. The differences between benign and malignant lesions were compared. Imaging features of SPN of lung cancer were summarized.

Of the 102 cases of SPN measuring less than 10 mm, 66 (64.7%) were benign lesions, 25 (24.5%) were primary lung cancer, and 11 (10.8%) were metastatic lung cancer. The benign lesions included inflammatory pseudotumor, benign tumor, lung tuberculosis, and so on. Primary lung cancers, including 6 advanced cases (stage IIA and higher stage), had several radiological features different from benign nodules, such as ill-defined margins, speculation, bronchus or vessel involvement. Also, the enhanced CT value was higher in malignant nodules than in benign nodules except inflammation pseudotumor. The SPNs of metastatic lung cancer had similar radiologic features to those of primary lung cancer.

SPNs measuring less than 10 mm are mainly composed of benign lung tumor and primary lung cancer.