Clinically Insignificant Pituitary Tumors

There is extensive medical literature regarding the psychological manifestations of both functional and endocrine inactive pituitary tumors. Patients may experience any one of a multitude of personality and psychiatric disorders as a consequence of perturbations in homeostasis due to either excess or deficient secretion of one or more anterior pituitary hormones. In some cases, these mental health disorders improve following successful treatment, but long-lasting residual effects are often evident, requiring patients, their families, co-workers, and physicians to cope with the changes in personality.

Little attention has been given to the issues that arise when patients are told they have a pituitary tumor or disorder that is incidental and not clinically significant. Generally, these disorders are not thought to cause clinical manifestations, represent immediate or latent threats to the patient’s health, or require any particular therapeutic interventions. We argue that all pituitary tumors are clinically significant. Many of these seemingly innocuous tumors cause psychological symptoms and signs and thus require treatment.

Pituitary tumors have been found in 10.6 to 27% of autopsied pituitary glands. In one study, MRI findings of a 3-mm or greater lesion were identified in 10% of a series of 100 subjects, with concordance between two radiologists. Interestingly, however, pituitary tumors become clinically apparent in only 18 per 100,000 persons. In this era of ready access to diagnostic medical care, an increasing proportion of patients with pituitary tumors are coming to medical attention with so-called “incidental pituitary tumors,” detected at the time of radiologic imaging procedures to evaluate potentially unrelated complaints.

Many of these tumors are truly incidental and no overt manifestations, such as mass effects due to the tumor, syndromes of hormone excess, or syndromes of hormone deficiency, are clinically apparent. Others, surprisingly, are endocrine-active tumors and patients are found to have subtle manifestations of a syndrome of hormone hypersecretion, such as acromegaly, Cushing’s syndrome, hyperprolactinemia, or hyperthyroidism, while others still may have recognizable mass effects due to their tumors, most commonly a headache syndrome, and partial or complete deficiencies of one or more anterior pituitary hormones.

In order to not miss the diagnosis, endocrinologists and other treating physicians are taught to evaluate patients with incidentally detected pituitary tumors for hormone abnormalities. In most cases, we recommend the following studies: prolactin, IGF-1, free T4, TSH, ACTH, and cortisol. In women of reproductive age who are amenorrheic, we check follicle-stimulating hormone (FSH), lutenizing hormone (LH), and estradiol levels. In postmenopausal women we check FSH levels. In men we check LH, FSH, and testosterone levels. Additional specific dynamic tests are based on the patient’s medical history, physical examination, and results of these screening tests. Unfortunately, when pituitary function is normal, patients are often told they have a clinically insignificant or unimportant pituitary tumor and follow-up is often recommended.

We argue that asymptomatic pituitary tumors are not entirely harmless for several reasons. First, simply telling patients that they have a tumor often leads to emotional distress regarding the uncertainty of the diagnosis and possibility of progression of the disease process. Furthermore, the process of follow-up testing results in periodic financial burdens and related stresses directly as a consequence of the need to pay for sequential MRI studies, laboratory tests, and indirectly via loss of time from work. Second, physicians are under increasing pressure to see more patients in a typical workday and, as a consequence, are spending less time with patients, are unable to fully explore patient symptoms and signs, and often do not make the association between common constitutional symptoms and pituitary tumors. In essence, there is no such thing as a clinically insignificant pituitary tumor.

Written by Lewis Blevins, Jr., MD