Two sections (A, B) of the nodule. The GS staining allows the distinction between non-nodular tissue and the nodule. The broken line delineates the frontier. Figures 9, 20–25 are from section A. The upper figure is from non-nodular tissue and the lower figure is from the nodular area. Figures 4-6 are from section B (blue rectangle). Figures 7, 8, 10-19 are from the same section (yellow rectangle). The upper and lower microphotographs illustrate the same area (serial sections).