A pituitary adenoma is a benign tumor in the pituitary gland, which controls metabolic processes in the body. Anaplastic adenomas are the most aggressive of all types of tumors. They are characterized by a high growth rate and the ability to penetrate into nearby brain tissue.
A feature of the histological structure of anaplastic adenomas is the presence of cells that have a high amount of cytoplasm and mitoses. These cells may be deformed and contain microscopic fragments of the nuclei of other pituitary cells. Also, many small calcified balls (lipomas) can be found in the tumors. These balls are formed by the remnants of previously destroyed tumor cells. The process of development of anaplastic pituitary adenoma is not fully understood. Most doctors believe that the development of tumors occurs due to the effects of environmental factors on healthy pituitary cells, as well as mutations in the tumor suppressor gene PTEN. Due to genetic