What Is a Pituitary Adenoma and Why Does It Matter?
The pituitary is the 'conductor' gland that governs the body's hormonal balance; it controls many systems such as the thyroid, the adrenal glands, the reproductive hormones and growth. Adenomas arising from it matter in two main ways. First, hormonal effect: some adenomas secrete excess hormone and produce, for example, prolactinoma (excess milk hormone, menstrual irregularity), acromegaly (excess growth hormone, enlargement of the hands, feet and face) or Cushing's disease (excess cortisol). Second, mass effect: a growing tumor can press on the crossing point of the optic nerves just above it (the optic chiasm), typically causing loss in the outer visual field of both eyes (bitemporal hemianopia). For this reason a pituitary adenoma is both an endocrinological and a surgical matter.
Diagnosis: Hormones, Visual Field and MRI
Assessment of a pituitary adenoma rests on three pillars. Hormone profile: pituitary and target-gland hormones are measured in the blood to determine whether the tumor is secreting and which hormone deficiency/excess is present. Visual assessment: if the tumor is near the visual pathways, an eye examination and visual field test are essential, because vision loss is the most important finding determining the urgency of surgery. Imaging: a pituitary-protocol contrast MRI shows the tumor's size, its extension into the cavernous sinus and its relationship to the visual pathways. A treatment decision is not made before these three pieces of information come together, because two adenomas of the same size can be managed completely differently according to the hormone profile and visual status.
Treatment: Medication, Surgery or Observation?
In pituitary adenoma the treatment option varies with the type of tumor. Prolactinoma is treated in most patients with medication (dopamine agonists) rather than surgery; in this tumor surgery is generally reserved for selected cases that do not respond to medication. By contrast, in other secreting adenomas causing vision loss or acromegaly/Cushing's, endoscopic surgery comes to the fore. Small, asymptomatic, non-secreting adenomas (found incidentally) may simply be followed with interval MRI and hormone checks. In large tumors causing acute vision loss, surgery is planned without losing time. The decision is always multidisciplinary; the neurosurgeon, endocrinologist and ophthalmologist evaluate together.
Endoscopic Transsphenoidal Surgery
When surgery is needed, the standard method today is the endoscopic transsphenoidal approach: the tumor is reached without opening the skull, through the nostrils, over the air space called the sphenoid sinus. Thanks to this route there is no incision scar on the face, the brain is not retracted and recovery is relatively fast. With a high-resolution endoscope the tumor is seen directly and removed while trying to preserve healthy pituitary tissue. The procedure is performed under general anaesthesia and takes a few hours; it is usually followed by a short hospital stay. The most important issues to monitor after surgery are a disturbance of water-salt balance that can be temporary (diabetes insipidus) and the monitoring of hormone levels; for this reason close cooperation with endocrinology continues.
Risks and Realistic Expectations
Endoscopic transsphenoidal surgery, while relatively safe in experienced hands, is not without risk; a cerebrospinal fluid leak, temporary or permanent hormone deficiency (which may require hormone replacement), disturbance of water-salt balance and, rarely, problems related to vision or vascular structures can occur. Outcomes vary with the type of tumor: in tumors causing vision loss, a marked improvement in vision is common when the compression is relieved early; in secreting tumors the chance of hormone normalisation depends on tumor size and extension. In some large adenomas or those extending into the cavernous sinus, medication or radiation treatment may be needed in addition to surgery. We do not promise a guaranteed result; expectations are shared openly before surgery according to your hormone, vision and MRI findings.