Pituitary tumors are pathological processes occurring in the pituitary gland, a structure with endocrine activity, located in the brain. Although its dimensions are very small, the pituitary has a very important role in the secretion of hormones that affect various organs and systems and participate generally in the maturing of the body.



Pituitary tumors represent 10-25% of all intracranial tumors by location. Pituitary disease symptoms are usually found in close examination because they are not immediately apparent as clear-cut signs of disease. Pituitary tumors are classified into 3 groups: Benign adenomas - tumors that are not cancer - They have a very slow growth rate and are not able to metastasize (to expand through the blood stream, the lymphatic system, in other parts of the body, at a distance from where the initial neoplasia took place).

Invasive pituitary adenomas - are tumors that are capable of expansion and invasion, especially in the cranial bones or sinuses located below the pituitary. Pituitary carcinomas - are malignancies (cancers). These are processes that extend into the central nervous system (brain and spinal cord) or outside it. Very few of pituitary tumors, however, are the result of neoplasia. This classification took into account the biological behavior of adenomas and their evolution, and is currently widely accepted by specialists in the field.

But most tumors are adenomas and only a small fraction of them are show pituitary disease symptoms. Invasive adenomas (35% of pituitary neoplasia cases) can invade the skull bones and the sphenoid sinus. Of all pituitary tumors, carcinomas represent 0.1-0.2%.

Pituitary adenomas can be classified according to:
The anatomy of the tumor – tumors are grouped according to size, which is determined from imagery measurements into: microadenomas (10 mm in diameter) and macroadenomas (over 1 cm diameter). Macroadenomas, in turn, can be split into encapsulated macroadenomas or invasive macroadenomas (localized or diffuse). Most tumors are microadenomas. This classification of adenomas according to size, extension and by exploring the invasineveness of the tumor using imagery is extremely detailed and complex.

Neurologic and radiologic scans include (among others):
- X ray of the skull (profile) to view the walls of the pituitary, to measure its diameters and then to classify adenomas.
- pneumoencephalography or PEG - is a more complicated method by which to view the amount of air that will deploy in the cerebrospinal fluid space above the sella turcica.
- carotid artery angiography - an investigation is carried out routinely in the laboratory analysis of pituitary tumors, but only if there are suspected vascular lesions.
- polytomography - special tomography is a method which makes detailed images (by consecutive sections) of the structures difficult to access, using a special device, able to perform complex movements.
- CT (computer tomography) - the modern method which can do sections at 3 mm distance. It has many advantages: viewing the structures surrounding the adenoma, capsule, integrity of bone walls and the invasive nature of the adenoma.

According to radio-anatomic classification, there are 4 stages of adenomas, as follows: Stage 1 - adenoma 1 cm in diameter, without extension to the sella; Stage 2 - macroadenoma (over 1 cm diameter) with possible extension to the sella; Stage 3 - macroadenoma with enlargement and invasion of the supersellar space; Stage 4 - macroadenoma that goes beyond the sella and walls.