Pituitary Adenoma

Definition

Pituitary adenomas are tumors of the pituitary gland and typically arise in the anterior pituitary. They are one of the most common intracranial tumors and are diagnosed most often in young or middle-aged adults, with an equal occurrence among males and females. Pituitary adenomas are typically benign and slow growing. They are usually classified as either microadenomas (<1 cm diameter) or macroadenomas (>1 cm diameter). Many pituitary tumors are asymptomatic and go undiagnosed. When they do come to clinical attention, it is due to endocrine dysfunction or visual abnormalities. Depending on the specific structures involved and the type of hormone secreted by the tumor, pituitary adenomas can cause impotence, infertility, amenorrhea, galactorrhea, thyroid dysfunction, Cushing’s disease, or growth irregularities such as acromegaly. If the optic chiasm is involved, headaches and visual deficits, particularly bitemporal hemianopsia, can result. Surgery, radiotherapy, and...