A pituitary adenoma is a primary brain tumor. It is the most common pituitary tumor. It comprises 10–15 percent of total brain tumors.
Classification
- Classification I
- Eosinophil (Acidophil) adenomas
- Chromophobe adenomas
- Basophil adenomas
- Prolactin-secreting adenomas
- Classification II
- Hyposecreting by compression and atrophy
- Hypersecreting
- Classification III
- Macronodular – Tumour size > 1 cm
- Micronodular – Tumour size < 1 cm
Phases
- Intrasellar growth
- Suprasellar expansion
- Enormous intracranial expansion.
Clinical features
- Headache
- Visual impairment in macroadenomas that compress the optic nerve and chiasm – typically bitemporal hemianopia
- Characteristics syndromes in endocrine-active adenomas
- Hyperthyroidism (TSH)
- Acromegaly (GH)
- Giantism (GH)
- Amenorrhea-galactorrhea (Prolactin)
- Impotence (Prolactin)
- Cushing’s disease (ACTH)
- Endocrine-inactive adenomas
- Hypopituitarism
Investigation
- Skull X-ray – shows calcifications, mass lesion, enlarged pituitary fossa, and destruction of sella turcica
- A magnetic resonance imaging scan
- Computed tomography scan.
- Evaluation of hormones – e.g., ACTH
Differential diagnosis
- Malignant variant
- Craniopharyngioma
- Aneurysm
- Rathke’s cleft cyst
- Meningioma
Treatment
- Surgery
- Transsphenoidal approach
- Massive tumors require a sub-frontal craniotomy
- Radiation therapy
- Done for tumors that cannot be completely removed
