A pituitary adenoma is a benign tumor arising from the pituitary gland located in the middle of the skull base under the brain. The pituitary gland is controlling other endocrine glands and therefore called an “orchestra conductor” of the body. It is itself under brain control. The pituitary gland has two parts which have different functions. Front part or adenohypophysis produces several hormones to control growth and development of the body, breastfeeding, adrenal and thyroid glands as well as hormones responsible for reproduction. Back part or neurohypophysis stores and releases vasopressin and oxytocin - hormones controlling water balance and womb contraction during delivery. Oxytocin is also known as a “cuddle hormone” or “love hormone” since it is released when people make social bondages.
A pituitary adenoma may secrete extra amount of hormone causing symptoms associated with an excess of hormone in the body. For example, if there is an excess of prolactin – the hormone responsible for breastfeeding then the patient will have galactorrhea – which is the abnormal production of milk or milk-like fluid. On the other hand, sometimes the tumor may compress the pituitary gland and cause pituitary insufficiency i.e. lack of most pituitary hormones in the body. Also, the pituitary adenoma may cause symptoms by compressing nearby structures – in the vast majority of cases optic nerve is affected. Optic nerves are connecting eyes with the brain and are responsible for vision. Therefore, a pituitary adenoma compressing the optic nerve will cause a visual disturbance – a very frequent symptom. In some cases, the pituitary adenoma may bleed and swell rapidly increasing in size a condition called pituitary apoplexy. This is an emergency condition because normal pituitary gland and optic nerves cannot adapt to rapid pressure and can get permanent damage.
Pituitary adenoma presents with endocrine pathology and compressive effect. Endocrine disturbances may include abnormal discharge from breasts, infertility, loss of libido, thyroid hypo and hyperfunction, increased and decreased steroids in the body, reproductive problems, the extreme growth in children and acromegaly (growth of hands, feet and facial bones) in adults. Compression usually affects the optic nerve but other nerves can be involved as well. For example, nerves providing innervation to eye muscles may be involved resulting in double vision.
Treatment of pituitary adenomas depends on several factors. There is an endocrinological and neurosurgical perspective. From the endocrinological perspective, it is important to restore the body’s hormonal balance. From the neurosurgical viewpoint, it is important to relieve the pressure from the important structures. Both treatment strategies are important and therefore usually these patients are treated with endocrinologists and neurosurgeons. Surgery is reserved for cases when there is uncontrollable hormonal excess and/or visual impairment. Some tumor types like prolactinomas are initially treated with medical therapy. Tumors that do not cause significant hormonal misbalance and optic nerve compression can be followed up with serial imaging.