Rare case study details double Cushing’s syndrome/disease diagnosis
Form caused by pituitary tumor masked by prolonged steroid exposure
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A Moroccan woman with Cushing’s syndrome caused by prolonged exposure to glucocorticoids was unexpectedly found to also have Cushing’s disease, the form driven by a tumor in the brain’s pituitary gland, a case report shows.
After stopping treatment with glucocorticoids, also commonly called corticosteroids or steroids, her cortisol levels remained abnormally high instead of falling as expected, ultimately leading doctors to uncover an underlying internal source of excessive cortisol and diagnose Cushing’s disease.
“Early recognition of this rare association is essential to avoid delayed diagnosis and ensure timely and appropriate management,” researchers wrote.
The study, “Is it Possible to Have Coexisting Exogenous and Endogenous Cushing’s Syndrome?” was published in Cureus.
Few cases of coexisting Cushing’s forms have been reported
Cushing’s syndrome encompasses a group of disorders marked by chronically elevated levels of the hormone cortisol. Over time, excess cortisol can cause a range of Cushing’s symptoms and complications, including weight gain, fatigue, skin changes, high blood pressure, and diabetes.
One form, called exogenous Cushing’s syndrome, usually develops after prolonged or excessive exposure to certain medications, usually glucocorticoids. These are a class of medication that mimic cortisol and are commonly used to treat inflammatory and autoimmune conditions.
Endogenous Cushing’s syndrome, meanwhile, occurs when the body produces too much cortisol on its own. In Cushing’s disease, the most common form of endogenous Cushing’s syndrome, a tumor in the brain’s pituitary gland releases excessive amounts of adrenocorticotropic hormone (ACTH), stimulating the adrenal glands atop the kidneys to produce cortisol.
“The association or coexistence of exogenous and endogenous CS [Cushing’s syndrome] is very rare, and only a few cases have been reported in the literature,” the researchers wrote.
Woman had been taking a glucocorticoid for 3 years to gain weight
In this report, doctors detailed the case of a 40-year-old woman in Morocco with exogenous and endogenous Cushing’s whose diagnosis proved particularly challenging.
The woman, who had been recently diagnosed with diabetes and high blood pressure, sought emergency care for severe fatigue, abdominal pain, and vomiting.
Doctors learned she had been taking dexamethasone, a glucocorticoid, every day for three years in an effort to gain weight and had stopped the medication 10 days before seeking medical attention.
Physical examination revealed several hallmark signs of Cushing’s, including prominent purple stretch marks across the abdomen and upper limbs, fat buildup around the abdomen contrasting with relatively thin arms and legs, a rounded “moon” face, and fat accumulation between the shoulders known as a “buffalo hump.”
Because prolonged glucocorticoid use normally suppresses the body’s own cortisol production, doctors initially suspected that the sudden withdrawal of long-term steroid treatment had triggered adrenal insufficiency. This condition occurs when the adrenal glands cannot produce enough cortisol and may cause severe fatigue, abdominal pain, nausea, and vomiting.
But further testing complicated the picture.
The coexistence of exogenous and endogenous CS is exceptionally rare and may represent a major diagnostic challenge. This report highlights the importance of maintaining a high index of suspicion for endogenous CS in patients receiving long-term corticosteroid therapy when the clinical course or biochemical findings are atypical
The woman’s blood cortisol level measured at 8 a.m. — when cortisol is normally at its daily peak — was far above the normal range. Her potassium levels were also markedly low, a finding that can occur with excessive cortisol levels. These findings did not fit what doctors would normally expect after prolonged steroid exposure.
“The possibility of concomitant endogenous CS was therefore raised,” the researchers wrote.
Biochemical testing suggested that elevated ACTH levels were driving her excess cortisol production. An MRI scan then revealed the likely source: a pituitary macroadenoma, a benign tumor in the pituitary gland. The woman was ultimately diagnosed with Cushing’s disease.
She underwent transsphenoidal surgery, a procedure to remove the pituitary tumor through the nasal cavity, and “the postoperative course was uneventful,” the researchers wrote. Follow-up testing later showed low cortisol levels, consistent with the temporary adrenal insufficiency often expected after successful surgery.
“The coexistence of exogenous and endogenous CS is exceptionally rare and may represent a major diagnostic challenge,” the researchers wrote. “This report highlights the importance of maintaining a high index of suspicion for endogenous CS in patients receiving long-term corticosteroid therapy when the clinical course or biochemical findings are atypical.”
Persistent excess cortisol, high blood pressure, and low potassium levels, “should prompt a comprehensive hormonal evaluation,” they added.
