What is an Adenoma

Pituitary Adenoma

Pituitary adenomas are benign tumors developed from the pituitary gland, a gland located under the brain in a bony compartment called the sella turcica. True “conductor” of the hormonal glands, the pituitary regulates many body functions. Management of adenomas is specialized and multidisciplinary; when surgery is indicated, the expertise of the neurosurgeon is essential. In an expert center, the outcome is favorable in the vast majority of cases.

Pituitary region (diagram).

Sagittal brain MRI showing the pituitary gland and its pituitary stalk — *Sagittal (profile) view brain MRI showing:*
The anatomical region of the pituitary (blue square).
The pituitary gland (yellow arrow).
The pituitary stalk connecting the pituitary to the brain (white arrow).

Types of Pituitary Adenomas

Depending on their size, a distinction is made between microadenomas (diameter < 1 cm) and macroadenomas (diameter ≥ 1 cm). Microadenomas often pose a problem of hormonal secretion (e.g., Cushing’s disease, acromegaly, prolactinoma). Macroadenomas rarely resolve spontaneously and mostly expose to a mass effect with a risk of damaging visual pathways.

Coronal pituitary MRI showing a microadenoma and optic pathways — *Coronal (frontal) view pituitary MRI showing:*
The pituitary microadenoma (white arrow).
The optic pathways at a distance from the microadenoma (green arrow).

Secreting or Non-Functional Adenoma

The hormonal assessment (blood test) allows classifying the adenoma into:

Secreting adenoma: excessive secretion of a pituitary hormone (e.g., prolactin in prolactinoma, ACTH/Cortisol in Cushing’s disease, GH/IGF‑1 in acromegaly…).
Non-functional adenoma (or non-secreting): absence of hormonal hypersecretion.

The therapeutic strategy differs depending on whether it is a secreting or non-functional adenoma, and depending on the volume and the relationship of the lesion with neighboring structures (especially visual pathways).

Frequency

Pituitary adenomas account for about 10 to 20% of intracranial tumors in adults. Their prevalence is estimated between 1/1000 and 1/1300 in the general population; the incidence is around 1/100,000 inhabitants per year. Adenomas responsible for Cushing’s disease or acromegaly are rarer and require ultra-specialized management.

Diagnosis

In the presence of endocrine, neurological, and/or ophthalmological symptoms, a brain/pituitary MRI is prescribed. Once the diagnosis is confirmed, a consultation with an endocrinologist and/or a neurosurgeon is organized.

Complementary Examinations

Endocrine Assessment (Pituitary Panel)
Assays: Prolactin, TSHus, FT4, FT3, FSH, LH, estradiol, progesterone, testosterone, ACTH, cortisol, IGF‑1. Objectives:
- Detect a hormonal excess (secreting adenoma).
- Search for hormonal insufficiency related to compression of the healthy pituitary.
An endocrinology consultation completes the management (specific treatment of secreting adenomas, or hormonal substitution in case of deficit).
Radiological Assessment
The pituitary MRI is the gold standard examination. It finely analyzes the extensions of the adenoma:
- Within the sella turcica: relationship with the pituitary gland.
- Extension suprasellar: relationship with the chiasm and optic nerves.
- Extension infrasellar: towards the sphenoid sinus.
- Lateral extension: towards the cavernous sinuses.
Depending on the case, a CT scan (angioscan, bone windows) may complete the evaluation and be used in neuronavigation to guide surgery. Complex cases are discussed with a referring neuroradiologist.
Ophthalmological Assessment
Often necessary due to the proximity of visual pathways. The examination generally includes:
- Measurement of visual acuity.
- Visual field study.
- Fundus examination and/or OCT depending on indication.

Treatments

The strategy is discussed in a Multidisciplinary Team Meeting (neurosurgeons, endocrinologists, radiologists, and depending on cases pathologists, biologists, radiotherapists, oncologists).

Therapeutic Options

MRI Surveillance: adapted to small, stable, and asymptomatic non-secreting adenomas.
Medical Treatment: first-line for many prolactinomas and certain secreting adenomas, initiated by the endocrinologist.
Resection surgery via endonasal route (endoscopic): indicated in multiple situations (secreting adenomas — Cushing’s disease, acromegaly, resistant microprolactinomas —; non-secreting adenomas of significant volume, threatening or compressing visual pathways, or progressive on MRI; intolerance/failure of medical treatments).
Radiotherapy / Radiosurgery: depending on context (post-operative residues, aggressive or rapidly progressive adenomas).

Endoscopic Endonasal Surgery

Objectives

Obtain the widest possible resection while preserving, if possible, normal endocrine functions. In case of lateral extension (invasion of the cavernous sinus), a remnant may be left to limit risk. For a secreting microadenoma without cavernous invasion, the goal is complete resection leading to remission.

Consultation with the Neurosurgeon

Link between your symptoms and the lesion.
Principle of the intervention via endoscopic endonasal route.
Resection objectives depending on extensions (invasive nature or not).
Care pathway at the hospital and post-operative follow-up.

Why the Endoscopic Route?

Gold standard technique today: the endoscope brings light to the back of the nasal cavities and offers a panoramic view (sella, supra- and infra-sellar regions, cavernous sinus), improving the resection of extensions. The minimally invasive routes respect the nasal cavities, reducing rhinological consequences and improving post-operative comfort.

Endoscopic view of the sellar region during endonasal surgery — Endoscopic view of the sellar region.

Minimally invasive endonasal access for pituitary surgery — Minimally invasive endonasal access.

Preoperative Assessment

Radiological assessment.
Endocrinology consultation.
Neuro-ophthalmological consultation if necessary.
Anesthesia consultation in case of surgery.