Early Lung Cancer With Lepidic Pattern

Adenocarcinoma in Situ, Minimally Invasive Adenocarcinoma, and Lepidic Predominant Adenocarcinoma

Wilko Weichert; Arne Warth


Curr Opin Pulm Med. 2014;20(4):309-316. 

In This Article

Lepidic Growth and Imaging Modalities

Lepidic growth can be predicted by imaging modalities to a certain extent. In computed tomography (CT), lepidic growth is mirrored by GGO, thus allowing the rough estimation of the 'lepidic' fraction of a tumor (e.g. pure GGO, part-solid nodule) already prior to surgery or in advanced tumor stages when only palliative treatment is feasible.[11,45–47] This has been demonstrated to be of prognostic value, especially in early-stage lung ADC.[48–53] On univariate analysis, the presence of a positive air bronchogram, size of nodule, and mass of nodule were significant factors that differentiated invasive ADC from AIS or MIA. On multivariate analysis, size and mass of nodule were significant determinants for invasive ADC.[54] In a series of 114 lesions with pure GGO, Ichinose et al.[55] reported that after morphological workup, 14% of the cases were diagnosed as MIA and only 12% as invasive cancer. Differential diagnosis of part-solid nodules includes focal inflammation, focal fibrosis, and organizing pneumonia. Furthermore, maximum standardized uptake values (SUVmax) on positron emission tomography (PET)/CT and mean apparent diffusion coefficient values have been reported to correlate well with the histologic differentiation of pulmonary ADC.[56] In pure GGO lesions, PET-positive tumors are associated with foci of invasion.[55]