Inhibiting steroid production with metyrapone, a common therapy used in Cushing’s disease, may not only normalize cortisol levels but also lead to the spontaneous remission of ectopic tumors producing adrenocorticotropic hormone (ACTH), according to a case study.
Researchers presented the case of a 71-year old women whose ACTH-producing lung tumor regressed spontaneously after treatment, without the need for surgery.
The study, “Spontaneous adrenocorticotropic hormone (ACTH) normalisation due to tumour regression induced by metyrapone in a patient with ectopic ACTH syndrome: case report and literature review,” was published in the journal BMC Endocrine Disorders.
While most cases of Cushing’s disease are caused by tumors in the pituitary gland, other tumors produced outside the pituary gland may also produce excess ACTH and induce the adrenal glands to release too much cortisol, leading to the disease. This is called ectopic Cushing’s disease.
Patients are usually prescribed medicines that inhibit the metabolic pathways of cortisol synthesis. These include ketoconazole and metyrapone, two therapies that act on the brain’s adrenal cortex and prevent steroid production.
Now, researchers at Aichi Medical University in Japan presented the case of a 71-year-old woman diagnosed with ectopic Cushing’s disease caused by a lung tumor producing excess ACTH.
The patient received treatment with metyrapone which normalized cortisol levels. Unexpectedly, the treatment also made the tumor shrink, bringing ACTH levels back to normal.
While other studies had shown normalization of ectopic ACTH levels in Cushing’s disease patients, “this is the first reported case of the regression of an ectopic ACTH-producing tumor following treatment with a steroidogenesis inhibitor as confirmed using functional imaging,” researchers wrote.
The processes that blockers of steroid synthesis suppress ACTH production are still unclear.
Researchers believe that steroid inhibitors may directly inhibit ACTH production, explaining the normalization of the hormone levels. They also hypothesize tumor hemorrhage or tissue death as possible causes for the ectopic tumor regression. Additional information is warranted in future studies.
Overall, researchers presented a rare case “in which ACTH production by a lung tumor was reduced by [metyrapone]. The tumor itself regressed spontaneously after the initiation of [metyrapone], indicating that this drug may reduce tumor size without surgery,” the authors concluded.