Pituitary Tumors

Abstract

Pituitary tumors are not uncommon and are diagnosed because of hormone disturbance, mass effect, or as an incidental finding when an imaging study is obtained because of head trauma or headache. The exact prevalence of pituitary tumors is not known, but autopsy studies of patients without suspected endocrine disease demonstrated an adenoma of the pituitary in up to 26% of specimens, and 40% of these produced prolactin with immunocytochemical staining (1). With more clinical awareness, improved hormone assays, and modern imaging (computed tomography[CT], magnetic resonance imaging [MRI]), diagnosis of a pituitary tumor is relatively straightforward. The presenting features of a pituitary tumor depend upon the type and size of tumor. Headache is a common feature and occurs with a microadenoma (<10 mm) or a macroadenoma (>10 mm). Unfortunately, many patients are mistakenly assumed to have a migraine syndrome resulting in a delay in diagnosis. A fairly consistent occurrence in premenopausal women and men is gonadal dysfunction, such as amenorrhea, oligomenorrhea, or infertility in women and decreased libido and erectile dysfunction in men. In postmenopausal women, the most common presentation is that of a mass—headache and/or visual loss. If the tumor compromises normal pituitary function, the patient may have secondary adrenal insufficiency, secondary hypothyroidism, secondary hypogonadism, and growth hormone deficiency; one or more pituitary deficiencies may occur. The occurrence of adrenal insufficiency or hypothyroidism, requires immediate replacement. Diabetes insipidus is uncommon in a patient with a pituitary adenoma. Diabetes insipidus as an initial feature is more suggestive of metastatic disease, sarcoidosis, a craniopharyngioma, or a Rathke’ s cleft cyst. The challenge is to determine the type of pituitary adenoma, the need for hormone replacement, and the appropriate therapy or therapies.