Adjacent parenchymal abnormalities in peripheral bronchogenic carcinoma: correlation of thin-section CT with histology.

Our purpose is to correlate thin section CT of peripheral bronchogenic carcinomas with histologically detected lymphatic or vascular invasion. Retrospective 3-year database search revealed 186 surgical resections for primary bronchogenic carcinoma, of which 58 had available preoperative imaging performed at our institution. Cases with prior surgery, nonconfirmatory pathology, remote imaging, or central location were excluded, resulting in a study population of 42 patients, 25 men, 17 women, with a mean age of 69 years. Imaging with 1-3 mm collimation was performed within a mean of 32 days prior to surgery. Histologic diagnoses included adenocarcinoma (n = 24, 57%), squamous cell carcinoma (n = 13, 31%), large cell carcinoma (n = 4, 10%), and small cell carcinoma (n = 1, 2%), with a mean tumor size of 27 mm. Three radiologists blindly and independently recorded bronchovascular thickening, septal and nonseptal opacities, and the extent of each beyond tumor margins: 1) <5 mm, 2) 5-10 mm, and 3) >10 mm. Lymphangio-invasion was correlated with imaging findings, tumor size, and histology. Adjacent parenchymal abnormalities were recorded in 40 (95%) of 42 masses, with isolated nonseptal opacities representing the most frequent abnormality in 21 (50%), followed by bronchovascular thickening in 16 (38%), and septal opacities in 12 (29%). Lymphangio-invasion was present in 16 (38%) of cases. The frequency of lymphangio-invasion was highest (53%) in cases with 2 or more positive findings, and extension beyond 10mm from the tumor margin. This trend did not achieve statistical significance by ROC analysis. Lymphangio-invasion was positively correlated with tumor size, P =.03, but not histology.In conclusion, parenchymal abnormalities beyond tumor margins shown by CT may be due to lymphangio-invasion but imaging findings did not reliably distinguish cases with and without lymphangio-invasion.