Purpose: To identify any particular imaging features on computed tomography (CT) in patients with confirmed adenocarcinoma with bronchioloalveolar (ABAC) features and known epidermal growth factor receptor (EGFR) and KRAS mutations.
Materials and methods: Institutional review board approval was obtained for this retrospective study. Seventy-seven pulmonary nodules in 64 patients with a histologic diagnosis of ABAC and known EGFR or KRAS mutation status were assessed. Of these, 23 patients who were negative for both EGFR and KRAS mutations were used as a control group. Lesion size, margins, and density (ground glass versus solid) were assessed. Statistical analysis using the two-tailed Fisher's exact test t test was performed with multiple different variables.
Results: Twenty-one (33%) of 64 patients had EGFR mutations, 20 (31%) of 64 patients had a KRAS mutation, and 23 (36%) had neither. In nine patients with an EGFR mutation, there were 10 nodules with some ground glass opacity (GGO) and in nine patients with a KRAS mutation, there were nine nodules with some GGO. Twenty-six (34%) of the 77 nodules had some GGO, and 12 (46%) of these 26 nodules were entirely GGO. Sixty-two (81%) of the 77 nodules had some solid component, which also included some that were mixed with GGO. Thirty-five (45%) of 77 nodules had air bronchograms. All five nodules (100%) with a high percentage of bronchioloalveolar carcinoma (>75%) had the appearance of GGO only. The presence of GGO on CT was not significantly associated with the presence of an EGFR mutation (p = 0.44) or with the presence of a KRAS mutation (p = 0.77).
Conclusions: In our sample of patients with ABAC, there was no specific CT appearance, which would correlate with either an EGFR mutation or a KRAS mutation, when compared with a control group of patients who did not have these mutations.