Sections showed diffuse sheets of large clear cells and smaller eosinophilic cells with well-defined cell borders. There was a thin walled fibrovascular network (Figure 2). The large cells contained abundant quantities of floculant to clear cytoplasm and a central round to oval nucleus, and were mainly distributed peripherally around the vessels. The smaller cells contained abundant eosinophilic granular cytoplasm, and a central round to oval or irregular nucleus with a perinuclear halo due to cytoplasmic clearing. These cells were mainly distributed centrally within the tumour sheets. Mitotic figures were rare.
Histochemically, tumour cells showed positive staining for Hale’s colloidal iron (Figure 3), and immunohistochemically, showed positive staining for cytokeratin and epithelial membrane antigen, and negative staining for vimentin.
