The pituitary gland, or hypophysis, is an endocrine gland about the size of a pea and weighing 0.5 g.
The pituitary gland is formed by the anterior lobe (Adenohypophysis) and the posterior lobe (Neurohypophysis). 

The Adenohypophysis is responsible for the secretion of five hormones responsible of many crucial physiologic functions. Prolactin is mainly responsible for lactation. Adrenocorticotropic hormone (ACTH) is responsible forthe secretion of corticosteroids by the adrenal glands. Thyroid stimulating hormone (TSH) controls the secretion of thyroid hormone by the thyroid gland. Growth hormone (GH) stimulates growth and cell reproduction and regeneration in humans .Gonadotropins, Follicle stimulating hormone (FSH) and Lutheinizing hormone (LH) are responsible for the secretion of sexual hormones (estrogens, progesterone, and testosterone). FSH regulates the development, growth, pubertal maturation, and reproductive processes of the body. LH triggers ovulation and corpus luteum development in females, and stimulates Leydig cell production of testosterone in males.
The Neurohypophysis is responsible for the secretion of two hormones. Anti-diuretic hormone (ADH) also known as vasopressin, is responsible for the retention of water by the kidneys. Oxytocin is responsible for the acceleration of labor thus facilitating birth, and for breastfeeding. These two hormones contributed to the survival of the human specie. ADH, released into the brain during sexual activity, initiates and sustains patterns of activity that support the pair-bond between the sexual partners. Oxytocin evokes feelings of contentment, reductions in anxiety, and feelings of calmness and security around a mate.

Pituitary tumors, mainly benign adenomas, arise primarily from the anterior pituitary gland. They account for approximatively 15 percent of primary brain tumors.
Microadenomas are tumors les than 1 centimeter in diameter, and macroadenomas are tumors larger than 1 centimeter in diameter. 

Symptoms caused by pituitary adenomas are related to hormone production and/or deficit, and/or to the mass effect the macroadenoma produces on the adjacent structures.

Typically, more than one specialist can be involved in the treatment of pituitary adenomas (neurosurgeon, endocrinologist, radiotherapist).

When it comes to surgery, the vast majority of pituitary adenomas are best removed through the nose (the TRANSSPHENOIDAL APPROACH). This minimally invasive technique permits to avoid any brain manipulation, and leaves no facial scar (see images below). 

ENDOSCOPIC PITUITARY SURGERY has become our GOLD STANDARD TECHNIQUE for removal of pituitary tumors. It permits better visualization of the tumor, better removal of tumor, and no trauma to nasal mucosa, in comparison to the classic microsurgical technique. Post-operative recovery is fast as return to normal  daily activities. 

Left: pre-operative MRI showing a macroadenoma growing upward and compressing the optic chiasm.
Right: post-operative MRI showing complete removal by the minimally-invasive transsphenoidal approach, leading to optimal decompression of the chiasm.

However, some huge macroadenomas are treated by a combination of 2 or 3 approaches, including transsphenoidal route, and
CRANIOTOMY, in order to control the intracranial part of the tumor (see images below).

Left: pre-operative MRI showing a huge macroadenoma growing upward and invading the lateral ventricule.
Right: post-operative MRI showing complete removal of the supra-sellar part of the tumor and resolution of the hydrocephalus, through a fronto-pterional approach.