Q&A

Pituitary Incidentaloma

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SHOULD AN ASYMPTOMATIC PATIENT BE EVALUATED FURTHER?
Endocrine Society guidelines2 recommend that all patients with pituitary incidentaloma, with or without symptoms, should undergo a complete history and physical examination and laboratory evaluation to exclude hypersecretion and hyposecretion of pituitary hormones.

The “classic” presentation of pituitary hormone hypersecretion—in the form of prolactinoma, adrenocorticotropic hormone (ACTH) excess (Cushing disease), growth hormone (GH) excess (gigantism/acromegaly), and TSH excess (secondary hyperthyroidism)—may be readily detectable on history and physical examination. Subtle cases, so-called subclinical disease, however, may exhibit little or no signs and symptoms initially but can be detrimental to the patient’s health if left untreated. For example, the estimated time from onset to diagnosis of acromegaly is approximately seven to 10 years—a delay that can significantly impact the patient’s morbidity and mortality.3

Prolactinoma can be more clinically apparent in premenopausal females due to irregular menstrual cycles (oligomenorrhea/amenorrhea). However, galactorrhea, or “milky” nipple discharge, occurs in only about 50% of women with prolactinoma and is extremely rare in men. Furthermore, the clinical presentation of prolactinoma in men is vague and related to hypogonadism, resulting from increased prolactin levels. Since men are essentially asymptomatic, these tumors can grow extensively (macroadenoma) and cause “mass effect,” such as headaches and visual impairment.

Therefore, without laboratory testing, abnormal pituitary function may go unrecognized.

WHAT LABS SHOULD I ORDER FOR THIS PATIENT?
Guidelines suggest an initial screening panel of prolactin, GH, insulin-like growth factor 1 (IGF-1), ACTH, early-morning cortisol, TSH, free T4, luteinizing hormone (LH), follicle-stimulating hormone (FSH), and testosterone.2

Note the use of “suggest” rather than “recommend.” Even among guideline task force members, there were differences in opinion as to whether certain tests (eg, TSH, LH, and FSH) should be included in initial screening. Those tests can be ordered at the clinician’s discretion, according to the level of suspicion, or can be added later if necessary.

Brian’s sample for laboratory testing is drawn at 7:50 am. Results can be found in the table (previous page).

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