Low Testosterone Linked to Pituitary Mass
Aaron* was a physically fit 45-year-old male sent to me by his wife for low testosterone, erectile dysfunction (ED) and chronically low libido. His low testosterone and other symptoms had historically been chalked up to anxiety, and he had been treated intermittently with anxiety medications, clomiphene, sildenafil and testosterone therapy. By all reports, he had a loving relationship with his wife, and he was unable to explain his ED and reduced sexual drive.
My review of Aaron’s labs revealed a markedly low testosterone level of 130ng/dL (normal for his age is 300 – 800ng/dL or arguably even higher). In addition, the hormone in his pituitary which usually stimulates testosterone production (LH) was quite suppressed. This can happen in the presence of weight gain and anxiety, but the degree of both testosterone and LH suppression concerned me.
In addition, Aaron’s had a slightly elevated prolactin hormone level. This can be caused by a number of factors, including pituitary masses. A subsequent pituitary MRI revealed the following: a 2.3cm pituitary mass pressing on his optic nerves which run just above the pituitary gland. Visual field testing (to make sure the optic nerves had not been compromised by the mass) was, thankfully, normal. One of the main complications of these macroadenomas (large pituitary masses >1cm) is irreversible loss of vision. Aaron denied any change in vision, but in retrospect reported chronic headaches and “pressure behind his nose” which he had attributed to sinusitis. After making sure that the mass wasn’t producing any other pituitary hormones, I sent Aaron to a neurosurgeon for resection of this mass (“transsphenoidal surgery”).
This case highlights the pitfalls of testosterone treatment without a proper workup. There is certainly nothing immoral about treating hypogonadal males with testosterone therapy in the appropriate setting, but this should only be done after a full endocrine evaluation. Low testosterone in men can be either primary or secondary. Primary hypogonadism refers to low testosterone levels that originate at the level of the testicles. In this case, chromosomal testing must be done to rule out a condition called Klinefelter syndrome, in which a man has an extra X chromosome. The importance of making this diagnosis lies in the increased risk of breast cancer in individuals with Klinefelters.
Secondary hypogonadism refers to low testosterone caused by normal testicles receiving decreased signaling from the brain. This can be caused by weight gain, stress, certain medications and drugs, sleep apnea, anorexia nervosa, chronic illness and pituitary masses. If the possibility of a pituitary mass is not addressed in men with very low testosterone, low LH and potentially high prolactin levels, the patient can develop permanent loss of vision.
After several days in the hospital following his transsphenoidal pituitary surgery, Aaron’s testosterone slowly trended up to the low-normal range and his prolactin level self-corrected. In addition, the headaches and pressure behind his nose resolved completely. His libido rose precipitously, much to the general delight of his wife. Only his ED remained a minor issue which is now easily corrected by low dose sildenafil.
*name has been changed
