Highly vascularised pituitary adenoma with diffuse (solid) growth pattern. Higher magnification shows uniform cells with broad eosinophilic cytoplasm and round to oval nuclei (Hematoxylin and Eosin, A 100×). The proliferation index is very low with approximately 3% of cells showing immunoreactivity against MiB-1 (B 200×). Some tumour cells show immunopositivity for prolactin in the peripheral areas of the cytoplasm (C 200×). However, no immunoreactivity was present that provided an antibody against the human growth hormone (hGH, D 200×).