Non-functioning Pituitary Adenoma
Non-functioning pituitary adenomas are tumors arising from the pituitary gland that do not cause a clinical syndrome of hormone excess. Because they grow slowly, they are usually diagnosed at a large size (macroadenoma) with symptoms from pressure on surrounding structures.
Última actualización: 2026-06-07
Definition
Non-functioning pituitary adenomas (NFPA) are tumors arising from the pituitary gland that do not produce a marked clinical picture from excess hormone secretion. They make up a substantial proportion of pituitary adenomas. Because they grow more slowly than functioning adenomas, they are often diagnosed later and at a larger size (macroadenoma over 10 mm). In current classification, the term 'pituitary neuroendocrine tumor' (PitNET) is also used for these tumors.
Classification and Features
Current classification groups pituitary tumors by cell lineage (transcription factor expression). Most non-functioning adenomas are gonadotroph (SF-1 lineage) tumors and generally follow a less aggressive course. Some subtypes (for example silent corticotroph adenomas) may behave more invasively and have a greater tendency to recur. Definitive classification is made by immunohistochemical examination of the tissue after surgery.
Symptoms
The most common symptoms come from the tumor pressing on surrounding structures. Pressure on the optic chiasm classically causes loss of the outer visual fields on both sides (bitemporal hemianopia), and visual acuity may decline. Headache is common. Suppression of normal pituitary tissue can cause hormone deficiencies (fatigue, sexual dysfunction, menstrual irregularity). Mild elevation of prolactin from stalk compression may occur. Sudden severe headache with vision loss is an emergency suggesting bleeding into the tumor (apoplexy).
Diagnosis
Contrast-enhanced pituitary MRI is the gold standard for diagnosis; it shows the tumor's size, suprasellar extension, relationship to the optic chiasm and cavernous sinus involvement (Knosp grading). Visual field testing (perimetry) is mandatory for both diagnosis and follow-up. Hormonal assessment investigates both pituitary insufficiency and occult hormone secretion (silent adenoma). Immunohistochemical examination after surgery provides the definitive diagnosis.
Treatment
When there is visual impairment, significant mass effect, hormone insufficiency or progressive growth, surgery is the first-line treatment. In modern practice surgery is largely performed via the endoscopic endonasal (through-the-nose) transsphenoidal approach. When the tumor encases critical structures such as the cavernous sinus, complete removal is not always possible; residual/recurrent tumor is treated with stereotactic radiosurgery or fractionated radiotherapy. Medical therapy plays a limited role in these tumors.
Follow-up and Prognosis
After surgery, follow-up uses visual field testing, pituitary MRI and a hormonal panel; replacement therapy is arranged for patients who develop hormone deficiency. Recurrence risk is lower when complete removal is achieved, but long-term monitoring is advised. In asymptomatic, small and non-growing tumors, a watch-and-wait approach may be appropriate. Outcomes differ by patient and cannot be guaranteed.
Referencias
- Greenberg MS. Greenberg's Handbook of Neurosurgery. 10th ed. Thieme; 2023:861-873.
- Winn HR, ed. Youmans Neurological Surgery. 6th ed. Saunders; 2011:1481-1509.
- Osborn AG, Hedlund GL, Salzman KL. Osborn's Brain: Imaging, Pathology, and Anatomy. 2nd ed. Elsevier; 2018:795-807.
- Freda PU, et al. Pituitary Incidentaloma: An Endocrine Society Clinical Practice Guideline. J Clin Endocrinol Metab. 2011.
Este artículo es informativo y no sustituye un examen médico. Las decisiones de diagnóstico y tratamiento son individuales.