Pituitary adenoma laboratory tests

Overview
Pituitary adenomas are tumors that occur in the pituitary gland, and account for about 10% of intracranial neoplasms. They often remain undiagnosed, and small pituitary tumors are found in 6 to 24 percent of adults at autopsy. Pituitary adenomas arise within the anterior lobe (adenohypophysis) of the gland. Tumors less than 1 cm are called micro adenomas. Clinical symptoms depend on whether the tumor is secreting or nonsecreting. Nonsecreting adenomas grow and compress adjacent structures, most commonly causing a bitemporal hemianopsia due to chiasmatic compression. Lateral extension into the cavernous sinuses can result in cranial nerve palsies.

Lab tests
Tumors which cause visual difficulty are likely to be macroadenomata greater than 10 mm in diameter; tumors less than 10 mm are microadenomata.

Some tumors secrete more than one hormone, the most common combination being GH and prolactin.

Prolactinomas are frequently diagnosed during pregnancy, when the hormone progesterone increases the tumor's growth rate. Headaches may be present. The diagnosis is confirmed by testing hormone levels, and by radiographic imaging of the pituitary (for example, by CT scan or MRI).