Figure 2

Biopsy nomenclature for lepidic growth pattern (‘BAC features’ or ‘BAC pattern’). (a) A semisolid nodule, a biopsy of which was obtained. The longer arrow passes through the ground-glass periphery of the nodule, resulting in the purely alveolar growth/lepidic pattern tumor sample in panel b. If the trajectory of the biopsy followed, the arrowhead through the mass a different potentially invasive area of the tumor may have been sampled ((a) CT scan, (b) H&E section, original magnification × 25).