Cushing’s syndrome resolves after kidney tumor removed: Case study
Disease as a cancer complication called a first of its kind by researchers
A woman who developed Cushing’s syndrome as a complication of kidney cancer saw her symptoms fully resolve after the tumor was surgically removed.
This is the first published account that definitively describes Cushing’s syndrome developing as a paraneoplastic (cancer-related) complication of this type of cancer and resolving after its removal, according to the researchers.
“While Cushing’s syndrome has many etiologies [causes], urologists must be aware that it might present itself as paraneoplastic syndrome of [renal cell carcinoma], rendering the need for surgery as soon as possible,” the researchers wrote about the woman’s case in “Cushing’s syndrome as a paraneoplastic feature of renal cell carcinoma: A case report,” which was published in Urology Case Reports.
Cushing’s syndrome is a broad term referring to conditions that are driven by excessively high levels of the stress hormone cortisol. In Cushing’s disease, one of its most common forms, a tumor in the pituitary gland produces and releases high amounts of a signaling molecule called adrenocorticotropic hormone (ACTH), which prompts the adrenal glands to overproduce cortisol.
Other types of tumors can produce and release ACTH, leading to Cushing’s syndrome, but it’s much more rare.
Cushing’s syndrome as complication of kidney cancer
In this case, a 47-year-old woman went to the hospital with many symptoms indicative of Cushing’s, including a rounded face, high blood pressure, and poorly controlled diabetes. Laboratory tests showed high cortisol and ACTH, suggesting an ACTH-driven form of Cushing’s syndrome.
Imaging tests identified a small mass on her right kidney. The diagnostic workup didn’t identify any other possible source for excess ACTH production.
The part of the kidney harboring the mass was removed in a surgical procedure called a partial nephrectomy and tissue analyses confirmed the mass was renal cell carcinoma (RCC), a form of kidney cancer.
Following the tumor’s removal, the woman’s blood pressure and blood sugar levels returned to normal ranges. Cortisol and ACTH levels also fell to normal, observations that confirmed her Cushing’s syndrome was caused by the tumor.
A review of the published scientific literature to look for other reports of RCC causing Cushing’s syndrome as a paraneoplastic complication offered very little. A report published in the early 1960s described three possible cases of RCC-associated Cushing’s, but the validity of these was questioned since they didn’t show many typical features of Cushing’s. Another case, published in 1988, documented Cushing’s associated with RCC that was only confirmed on autopsy after the patient died.
“To our surprise, we found very limited evidence in the English literature regarding Cushing’s syndrome as a paraneoplastic feature of RCC. While we found our case to be an interesting presentation of RCC, we did not anticipate having to thoroughly examine English data from over  years ago until the present time,” the researchers wrote. “To the best of our knowledge, this is the first reported case of Cushing’s syndrome as a paraneoplastic feature of RCC in English literature, which demonstrated complete resolution following the surgical removal of the RCC.”