Fig. 2

Morphological characteristics of the tumour. H&E staining. A Lower magnification showing a clear boundary, with thick fibromuscular tissue separated from normal renal tissue. (Original magnification ×6). B Tumour cells were arranged in acinar or glandular tubular shapes, with homogeneous pink staining in a few acinar cavities. The cell cytoplasm was transparent or slightly eosinophilic, and the boundary was vivid. (Original magnification ×100). C Most of the nuclei were located at the base, and some of them were irregular in shape; nucleoli could be seen in some cells. (Original magnification ×200). D Among the cancer cells, there were oval or polygonal cells with a flaky distribution and an obvious capillary network. Some areas are loose and edematous and devoid of cells, with a rich mesh of capillaries. (Original magnification ×40). E Tumour cells varied in size and possessed a pale or eosinophilic cytoplasm that sometimes contained sharply delineated fine vacuoles and hyaline globules. (Original magnification ×400). F Focal haemorrhage, haemosiderin deposition, and psammoma bodies were observed. Transition between haemangioblastoma-like area and CCRCC-like area could be seen. (Original magnification ×100)