Prediction of lung tumor palpability using high-resolution computed tomography

Palpation is the most important means of locating lung tumors and resecting them with sufficient margins. This study aimed to predict the palpability of pulmonary lesions using high-resolution computed tomography.

Eighty-six pulmonary lesions were palpated in fresh resected lung specimens from July 2013 to March 2014. The following parameters were compared between 10 impalpable and 76 palpable lesions: maximum tumor size in pulmonary and bone window level settings, consolidation tumor size in pulmonary window level setting, and pleural-tumor distance. In 54 adenocarcinomas, the lepidic component and fibrosis foci rates were compared between the two groups.

Tumor size in bone window level setting and the consolidation tumor size were significantly smaller in the impalpable group (both p < 0.001), and an operational cutoff of 5 mm was identified by receiver-operating characteristic analysis (sensitivity/specificity was 90.0%/94.7% and 90.0%/86.9%, respectively). Pulmonary lesions were impalpable with 87.5% probability when the tumor size in bone window level setting was ≤ 5 mm and the pleural-tumor distance was ≥ 5 mm, and with 85.7% probability when the consolidation tumor size was ≤ 5 mm and the pleural-tumor distance was ≥ 5 mm. Lepidic component and fibrosis foci rates of impalpable/palpable lesions were 96.0%/52.8% and 4.0%/24.7%, respectively (both p < 0.001).

Tumor size in bone window level setting or a consolidation tumor size ≤ 5 mm and pleural-tumor distance ≥ 5 mm are simple criteria that are potentially useful indicators for preoperative marking to locate small-sized lepidic-predominant adenocarcinomas with few fibrotic foci.