Pituitary Tumors: Causes, Symptoms, Diagnosis and Treatment — Overview, Diagnosis & Treatment Options | MyMedicPlus

Pituitary tumors (adenomas) are the most common intracranial tumor type after gliomas, accounting for approximately 15-20% of all intracranial neoplasms. Most are benign adenomas. They are classified as functioning (hormone-secreting) or non-functioning, and by size as microadenoma (<1 cm) or macroadenoma (>1 cm).

Most cases are sporadic somatic mutations (GNAS in GH-secreting tumors, USP8 in ACTH-secreting). Hereditary syndromes include MEN1 (menin mutation), Carney complex (PRKAR1A), familial isolated pituitary adenoma (AIP mutation), and X-linked acrogigantism (GPR101). Pituitary carcinomas are extremely rare.

Functioning tumors: acromegaly (GH excess: enlarged hands, jaw prognathism, sleep apnea), Cushing's disease (ACTH excess: central obesity, purple striae, hypertension), hyperprolactinemia (amenorrhea, galactorrhea, infertility in women; erectile dysfunction in men). Non-functioning: bitemporal hemianopia, headache, hypopituitarism. Apoplexy: sudden severe headache with visual loss.

MRI pituitary with gadolinium and thin cuts (3 mm) is the diagnostic standard. Hormonal assessment: prolactin, IGF-1, 24-hour UFC or midnight salivary cortisol, ACTH stimulation test, TSH, LH, FSH, testosterone/estradiol. Formal visual field perimetry. Inferior petrosal sinus sampling (IPSS) for Cushing's disease lateralization and confirmation.

Prolactinomas: dopamine agonists (cabergoline first-line) achieve normalization of prolactin and tumor shrinkage in most cases. ACTH/GH-secreting and clinically significant non-functioning adenomas: transsphenoidal surgery is primary treatment. Adjuvant radiotherapy (stereotactic radiosurgery or fractionated) for residual or recurrent disease. Pasireotide or mifepristone for Cushing's disease resistant to surgery.

Prolactinomas respond excellently to cabergoline in over 90% of patients. Cushing's disease surgical remission: approximately 65-90% at experienced centers, with significant recurrence rates. GH adenoma biochemical remission after surgery: approximately 75-80%. Pituitary carcinoma: very rare, very poor prognosis with median survival approximately 3-4 years.