Figure 17a. Adenocarcinoma with no mediastinal or hilar lymph node metastasis in a 66-year-old man. (a) Transaxial thin-section (1-mm collimation) CT scan (lung window) obtained at the level of the right upper lobar bronchus shows a 14-mm nodule with a lobulated margin in the right upper lobe. (b) Low-power photomicrograph (original magnification, x12; avidin-biotin complex method) obtained after immunostaining for VEGF shows weak cytoplasmic positive staining. (c) High-power photomicrograph (original magnification, x100; avidin-biotin complex method) obtained after immunostaining for microvessel density with CD 31 shows few stromal microvessels, a finding that suggests low vascularity. (d) On a dynamic enhancement study consisting of CT scans obtained with the same parameters as those in Figure 16d, the nodule had a peak enhancement of 84 HU, a net enhancement of 38 HU, and a time to peak enhancement of 80 seconds (moderate enhancement). Scale at left is in Hounsfield units. On an FDG PET scan (not shown), the nodule demonstrated less glucose uptake than other non-small cell lung cancers.