Weight gain is a common concern for many patients with hormone problems, including those with adrenal tumors.

Weight Gain and Adrenal Tumors

Benign (non-cancerous) adrenal tumors can cause hormone over-production leading to weight gain. The hormone being over-produced depends on which cell in the adrenal gland it arose from. Specifically, with regard to weight gain and adrenal tumor-type, the tumors arising from the outer layer, or adrenal cortex, can frequently cause weight gain. 

Weight gain and cortisol over-producing adrenal tumors, Cushing’s syndrome

Cushing’s and subclinical Cushing’s syndromes can be caused by cortisol over-production from an adrenal tumor.  In subclinical Cushing’s, oftentimes an adrenal tumor over-produces cortisol without the obvious, or overt, signs and symptoms (some discussed here below) seen with Cushing’s syndrome.  Subclinical Cushing’s is more common, and thus, perhaps the cortisol level will be mildly elevated and only some of the signs of weight gain will be present. Please note that there is significant variability in symptoms of Cushing’s syndrome. Yes, we see skinny patients with cortisol-producing adrenal tumors and Cushing’s syndrome every week!

Regardless of whether the adrenal tumor is causing Cushing’s or subclinical Cushing’s syndrome, one of the most common universal features of the excess cortisol is weight gain, typically involving the face, neck, or belly. Often, the legs tend to lose fat, and become very slender. Fat can also be distributed in the cheeks creating a “moon face” appearance.  A hump can occur over the back of the neck due to fat distribution.  Fat can also accumulate over the collar bones resulting in a short and wide-appearing neck. 

The clinical manifestations of Cushing’s syndrome tend to be less severe in those over 50 years of age. 

Further, not all patients with Cushing’s syndrome will develop diabetes.  It is easy to conclude that excess cortisol production from an adrenal tumor causing weight gain equates to developing diabetes.  However, the estimated incidence of diabetes in those with cortisol-producing adrenal tumors is roughly 20-50%.  The excess cortisol causes the body to decrease insulin secretion.  Insulin helps to bring the sugar (byproduct from the excess cortisol) into the muscle, fat, and liver cells so that it can be converted into energy.  Less insulin equals more sugar in the blood stream making for an increased, but not absolute, risk for the development of type II diabetes.

Cortisol aids in the body’s stress response.  Small, infrequent, and non-sustained rises in cortisol are healthy in a stressful situation and allow us to respond in an appropriate manner to deal with the stressor.  However, when cortisol levels are persistently and chronically elevated from Cushing’s syndrome, your body cannot turn-off the stress response.  We have all heard of (and probably participated in) stress eating.  This phenomenon is directly related to the overflow of cortisol, which will in turn contribute to weight gain.

Figure: Typical fat distribution in a patient with Cushing’s syndrome

Changes in the body’s fat tissue at a cellular level is caused by the cortisol over-production from the adrenal tumor.  The cortisol slows down metabolism and increases appetite.  So, not only are you wanting to eat more, but the excess cortisol is causing the fat redistribution and changes within the fat, further promoting weight gain. Another vicious cycle of weight gain is created.  Are you seeing the pattern here?  Weight gain with these adrenal tumors is inevitable.  How to break the cycle? Successful surgery to remove the adrenal tumor causing hormone excess.

After successful adrenal surgery for Cushing’s or subclinical Cushing’s syndrome, the patients tend to lose weight. The amount and speed of weight loss is somewhat related to how high the cortisol levels were before the operation. Simply, the higher the cortisol level, the faster and more significant the weight loss will be. Again, there exists significant variability between patients. Any time a cortisol-producing adrenal tumor is removed, it takes weeks to months for the body to heal from the toxic effects of too much cortisol. Thus, it often takes weeks to months, and occasionally years for the weight to drop and normalize.

Learn more about Cushing’s syndrome symptoms, diagnosis, and treatment.

Weight gain and adrenal cancer

About 60% of adrenal cancers overproduce cortisol and thus these patients often demonstrate very rapid weight gain. The mechanism is the same as for patients with non-cancerous adrenal tumors over-producing cortisol. The difference is that often, the weight gain is very rapid and pronounced and happens over a much shorter period of time. Patients with adrenal cancer can gain significant weight 10—30 lbs. in just a few weeks to months. Some patients with adrenal cancer notice increased abdominal girth (usually seen as pants and other clothes not fitting) simply from the mass effect from a large adrenal cancer.

Weight loss can also occur in adrenal cancer, especially in patients with a more aggressive cancer that has already spread to liver and lung, as well as other tissues.

Weight gain and non-functional adrenal tumors, so called adrenal incidentalomas

A non-functional adrenal tumor (NFAT) is defined as a growth on the adrenal glands that produces no cortisol or any other hormones. Non-functional means that it is non-hormonal. It is not over-producing any hormones. This must mean, it cannot have any effect on your weight, right? Well, not so fast. Over the last five years, there has been a number of studies proving that NFATs are not as innocent as they may seem. In fact, they have been related to both diabetes and poor cardiovascular outcomes.

Thus, it is reasonable to assume that even non-functional adrenal tumors may be related to weight gain as well.

A few things are too early to tell based on current scientific knowledge:

• Are the detrimental effects of NFATs due to a slight overproduction of cortisol, which is lower than can be measured by the currently available assays used to measure cortisol? Put another way, the patients really have subclinical Cushing’s syndrome, we just lack the diagnostic tools to accurately diagnose the patients. or
• Is the effect due to overproduction of some other hormone which we are not currently measuring?

Let us review some scientific literature from two very reputable medical journals and research groups.

From

• Geach T. Adrenal gland: 'Nonfunctional' adrenal tumours increase diabetes risk. Nature Rev Endocrinol. 2016
• Lopez D, et al. "Nonfunctional" Adrenal Tumors and the Risk for Incident Diabetes and Cardiovascular Outcomes: A Cohort Study. Ann Intern Med. 2016

“Patients with nonfunctional adrenal tumors (NFATs), defined as growths on the adrenal gland that secrete no or very little cortisol, are at greater risk of developing diabetes mellitus than patients without adrenal tumors according to new research. Investigators reviewed medical records to identify 242 patients with NFATs and compared their long-term outcomes with those of individuals who had no evidence of an adrenal tumor (n = 1,237). Over a mean follow-up period of 7.2 years, 11.7% of the control individuals developed diabetes mellitus, defined as the presence of prediabetes or type 2 diabetes mellitus, compared with 27.3% of those with an NFAT.

The presence of an NFAT conferred a 15.6% increase in the risk of developing diabetes mellitus (95% CI 6.9–24.3%). Finally, when the team included patients with subclinical hypercortisolism in the analysis, 32% of individuals developed diabetes mellitus, which suggests cortisol levels have a graded effect on the risk of developing the disease.

“The study findings showed that even though we consider these adrenal tumors to be ‘nonfunctional’, the minuscule amounts of cortisol that they secrete may increase the risk of developing diabetes mellitus,” says Anand Vaidya, who led the study. “Future research involving interventions (either medical or surgical) will be needed to confirm whether the risk of diabetes mellitus associated with these adrenal tumors can be mitigated.”

Learn more about adrenal incidentalomas, diagnosis, and treatment.

Weight gain and aldosterone over-producing adrenal tumor, Conn’s syndrome

The link between aldosterone, obesity, and weight gain has been studied in detail.  Aldosterone levels are already elevated in obese individuals (without an adrenal tumor).  In fact, aldosterone protects fat.  Fat cells can stimulate aldosterone release from adrenal tissue.  Thus, with an aldosterone-producing adrenal tumor, a vicious cycle of weight gain is also created.

The excess aldosterone produced by the adrenal tumor causes salt retention by the kidney, which in turn causes water retention, as the available body water attempts to dilute the salt at a cellular level.  The increased salt and water retention causes weight gain and high blood pressure.  The excess fat will further promote aldosterone release from the adrenal gland. 

The cycle can only be broken by surgery to remove the affected adrenal gland containing the aldosterone over-producing tumor.  With the adrenal tumor gone, the body can begin to return to equilibrium, or normalcy.  The excess fluid can be shed, and in turn, weight can be lost.  Plasma aldosterone levels decrease following successful surgery and weight loss.  Blood pressure falls after the surgery.  Blood pressure continues to fall even further with additional weight loss, since less aldosterone production by the self-preserving fat cells.

Weight gain and adrenaline over-producing adrenal tumor, pheochromocytoma

Patients with pheochromocytoma have overproduction of adrenaline-type hormones such as epinephrine and norepinephrine, also known as catecholamines. Since too much of these hormones affect every cell of the body, it can also affect a patient’s weight.

In fact, there is a famous old-fashioned saying in medical endocrinology that goes like this, “forget a fat pheochromocytoma.” This served as a medical student reminder that most patients will have lost weight prior to having been diagnosed with a pheochromocytoma.

I say this is old-fashioned because again there is significant variability between patients. It is true that some patients with pheochromocytoma lose weight because of the significant effects of too much adrenaline hormone. However, some patients are also certainly both overweight and obese. We see this every week. This means that just because you are slightly overweight or frankly obese does not rule out a pheochromocytoma.

Compared to other adrenal tumor patients with cortisol- and aldosterone- producing tumors that tend to lose weight after operation, pheochromocytoma patients on average tend to gain some weight after successful surgery. However, this tends to be only in those patients that have had significant weight loss due to the pheochromocytoma, with weight “normalizing” after successful surgery. Put in a different way, most patients with pheochromocytoma do not gain or lose weight before surgery, and most patients have stable weight after curative surgery.

Weight gain and thyroid and parathyroid problems

Changes in your weight can also be related to thyroid disease. Learn more about thyroid disease and thyroid surgery.

Learn more about weight gain and parathyroid disease (hyperparathyroidism).

Additional Resources: 

Learn more about the Carling Adrenal Center

Learn more about Dr. Tobias Carling

Learn more about our sister surgeons at the Norman Parathyroid Center, Clayman Thyroid Center and Scarless Thyroid Surgery Center