ACTH-producing Lung Tumors Hard to Detect, But May Be Cured with Surgery, Case Report Shows
Ectopic Cushing’s syndrome can be challenging to diagnose, especially when it comes identifying the problem source. But appropriate hormone management protocols, used in combination with advanced imaging methods, may help physicians identify ectopic ACTH-producing tumors.
The findings in a case report of a young man with ectopic Cushing’s syndrome were published in the International Journal of Surgery Case Reports, under the title “Case report: Ectopic Cushing’s syndrome in a young male with hidden lung carcinoid tumor.”
Cushing’s syndrome is caused by high amounts of glucocoticosteroids in the blood. The most common cause is a malfunction of the glands that produce these hormones. In some cases, however, the disease may be caused by tumors elsewhere in the body that have the ability to produce adrenocorticotropic hormone (ACTH).
In half of all Cushing’s patients, ectopic ACTH is produced by small lung cell carcinomas or lung carcinoids (a type of slow-growing lung cancer). But some tumors in the thymus and pancreas also have been found to produce ACTH.
Researchers at Damascus University Hospital in Syria presented the case of a 26-year-old man who had ectopic Cushing’s syndrome due to lung carcinoids.
The patient presented with increased appetite and rapid weight gain for more than a year. These were associated with headache, fatigue, proximal muscle weakness, and easy bruising. He had no family history of hormonal disorder.
Based on the initial physical and symptom evaluation, the clinical team suspected Cushing’s syndrome. Blood analysis revealed high levels of cortisol and ACTH hormones, which supported the diagnosis.
Administration of dexamethasone, a treatment used to inhibit the production of glucocoticosteroids by the pituitary gland, reduced cortisol levels within normal range, but not ACTH levels. This led to the diagnosis of ectopic Cushing’s syndrome.
The next step was to identify the tumor causing the syndrome. The team conducted imaging studies of the brain, chest, and abdomen, but found no tumor.
Because ectopic ACTH is commonly produced by lung cancers, the team then analyzed the patient’s lungs. Again, they failed to detect a tumor.
The patient was discharged with prescription of 200 mg of Nizoral (ketoconazole) once-daily, calcium, and vitamin D. After three months of treatment, he remained stable, with no evidence of symptom improvement.
At this point, the team decided to surgically remove both adrenal glands in an attempt to reduce the hormone levels. Treatment with prednisolone 5 mg and fludrocortisone 0.1 mg once daily was initiated, along with calcium and vitamin D.
Eighteen months later, the patient’s condition worsened and he required hospitalization.
Imaging tests targeting the neck, chest, and abdomen were conducted again. This time, physicians detected a 2 cm mass in the middle lobe of the right lung, which was removed surgically. Detailed analysis of the small tumor confirmed that it was the source of the excessive ACTH.
“ACTH secreting tumors can be very hard to detect,” the researchers stated. “Initial failed localization is common in ectopic ACTH syndrome and it is usually due to carcinoid.”
Cases where the ectopic ACTH production is caused by a carcinoid tumor can be challenging to diagnose because tumors are small and relatively slow-growing. Imaging data is often hard to analyze and the tumors can be confused with pulmonary vessels, the researchers explained.
“In such cases we should first aim to lower blood cortisol medically or through bilateral adrenalectomy to avoid Cushing’s complications,” which should then “be followed up through imaging studies (CT, MRI, scintigraphy or PET) to detect the tumor and resect it, which is the definitive treatment of these patients,” the researchers concluded.