Figure 3b-4: Sparsely granulated somatotroph adenoma. Sparsely granulated somatotroph adenoma cells are pleomorphic and chromophobe on HE stain (top left) and PAS-OG histochemistry (top right). Fibrous bodies can be seen as pale discs in the cytoplasm on routine stains (arrows). As the name implies, sparsely granulated cells show weak, patchy GH expression (bottom left) and their keratin cytoskeleton is disrupted and condensed into a paranuclear globular structure – the fibrous body (bottom right).