The pituitary is a small endocrine gland found within a bony structure in the skull called the sella turcica. It is located below the optic chiasm and hypothalamus and is connected with the latter by the hypothalamic-pituitary stalk. There are important structures in the area around the pituitary such as the optic nerves, the cavernous sinus, carotid arteries and some cranial nerves.
The pituitary gland is divided into two parts:
- Anterior (adenohypophysis).
- Posterior (neurohypophysis).
The pituitary gland produces certain hormones (ACTH, TSH, GH, PRL, LH and FSH) that control the secretion of endocrine glands in the rest of the body. It has a very important role in the regulation of some vital features like:
- Sexual development and behavior.
- Functions related to reproduction, pregnancy and lactation.
- Funciones relacionadas con la reproducción, embarazo y lactancia.
- The metabolism.
- Energy balance of the body.
- Response to stress.
- Regulation of water and ion balance.
A pituitary adenoma is a benign tumor of the anterior part of the pituitary (adenohypophysis). These adenomas can be classified:
- From the functional point of view:
- Non-secreting (do not produce hormones)
- Secreting (produce hormones and cause syndromes of hormonal hyper secretion).
- Classified by size: :
- Microadenomas (less than 1 cm in diameter)
- Macroadenomas (greater than 1 cm in diameter)
The pituitary adenoma must be differentiated from other types of tumors located in the same anatomical region such as meningiomas or craniopharyngiomas.
Pituitary adenomas account for approximately 10% of all primary intracranial tumors with a prevalence of around 70-100 cases per 100,000 persons.
Symptoms in producing adenomas are related with the hormone they produce causing changes in the menstrual cycle, decreased sex drive, changes in blood pressure, changes in ion levels, milk secretion, bone growth, etc.
At times the symptoms are a result of tumor growth that affects the surrounding organs causing headaches, visual disturbances, etc. in the patient.
iTAcC is a multidisciplinary center, both open and active. In the case of a suspected pituitary adenoma the patient is evaluated by endocrinologists, ophthalmologists, neuroradiologists, neurosurgeons and radiation therapists. They work together to accurately complete the diagnostic protocol and establish guidelines for the best treatment in each case based on the levels of scientific evidence.
In the diagnostic protocol as well as in the clinical history hormonal determinations are performed in order to detect altered functionality. Sometimes it is necessary to complete the hormonal study with dynamic functional tests.
The field of vision examination by an ophthalmologist is very important because if the lesion compresses the optic chiasm then it can produce irregularities. If a macroadenoma affects the cavernous sinus it can disturb the nerves that regulate eye movements and cause double vision (diplopia). The ophthalmologist performs the Lancaster test to determine which ocular motor muscle is affected.
The magnetic resonance imaging (MRI) with or without gadolinium is the most important diagnostic test for evaluating a pituitary adenoma. It allows for the identification and characterization of pituitary lesions however small. Neuroradiologists at iTAcC have extensive experience in the diagnosis of this pathology.
- As a first choice, prolactin-producing adenomas from the growth hormone (GH) and thyroid stimulating hormone (TSH) must be evaluated by the endocrinology team and medical treatment guidelines established.
- The recommended treatment at iTAcC in cases of nonfunctioning macroadenomas that cause irregularities in the field of vision and micro or macroadenomas producers of GH, ACTH and TSH is: evaluation by neurosurgeons to determine if surgery is needed. If indicated, then it is performed using latest generation 3D neuronavigation systems.
Radiosurgery or stereotactic body radiation therapy (SBRT) is the therapeutic option in cases of pituitary adenomas when medical or surgical treatment has failed to control the disease. Radiosurgery and SBRT acts on adenomas which produce an excess of hormones in order to control the clinical problems (acromegaly, Nelson syndrome) or macroadenomas to prevent their growth from affecting adjacent structures described previously.
The system of radiosurgery and SBRT (Truebeam-STx]) available at iTAcC allows for treatments while protecting the optic pathway. A high-resolution MRI is done to accurately determine the location of the adenoma as well as define the chiasm and optic nerves with extreme accuracy which translates into safety and security of the optic pathway.
The iTAcC team will set up periodic checkups after completing treatment. They will include various tests that will change over time with the sole purpose of controlling the progress of the disease.
iTAcC has the means to monitor and control the progress of patients who have had a pituitary adenoma. The follow-up, like any therapeutic activity in iTAcC, is personalized and is done in cooperation with doctors involved in the diagnosis and treatment of each case.