Peliosis is characterised by multiple blood-filled lakes or cavities within parenchymatous organs. Typically found in the liver, spleen, bone marrow and lymph nodes, it has also been described in other organs such as lungs, kidneys, parathyroids and pancreas. The mechanism responsible for the development of peliosis remains unknown. (1) A 69 year-old man with a 6-year history of acromegaly underwent transsphenoidal surgery for pituitary adenoma. Morphologic findings demonstrated a plurimorphous plurihormonal pituitary adenoma consisting of somatotrophs, lactotrophs and mammosomatotrophs. The tumor contained several blood-filled cavities characteristic of peliosis. (2) A 61-year-old man with a prolactin-producing pituitary adenoma who underwent transsphenoidal surgery. In the tumor, peliosis was noted. Peliosis in a pituitary adenoma is an intriguing finding. The question arises whether it represents vasculogenic mimicry.