Rare lung tumor tied to Cushing syndrome, acromegaly
Surgery eased symptoms and corrected excess hormone activity
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A rare lung neuroendocrine tumor was linked to both Cushing syndrome and acromegaly, a disorder marked by enlarged hands and feet, in a 43-year-old woman in India, according to a case report.
The tumor produced adrenocorticotropic hormone (ACTH), which led to Cushing syndrome. Findings also suggested growth hormone-releasing hormone (GHRH)-related activity, which drove excess growth hormone production and acromegaly.
Tumor linked to two hormone-related disorders
Surgical removal of the tumor corrected the hormone excess and led to a marked easing of symptoms.
The study, “A rare case of dual hormone-secreting pulmonary neuroendocrine tumor causing concurrent Cushing syndrome and acromegaly,” was published in JCEM Case Reports.
Cushing syndrome is a group of disorders caused by chronically elevated cortisol levels. When the excess cortisol results from overproduction of ACTH by a pituitary tumor, the condition is specifically called Cushing’s disease.
ACTH is normally produced by the pituitary gland, a small gland located at the base of the brain. It stimulates the adrenal glands to produce cortisol. In some cases, however, tumors outside the pituitary gland can also produce ACTH, leading to excess cortisol production and Cushing syndrome. This form is known as ectopic Cushing syndrome.
Neuroendocrine tumors, or NETs, arise from hormone-producing cells found throughout the body. In rare cases, these tumors may release ACTH, leading to ectopic Cushing syndrome. Even more rarely, they may produce ACTH along with other hormones.
Here, clinicians in India described a rare case in which a pulmonary NET produced ACTH and appeared to have GHRH-related activity. While ACTH drove excess cortisol production and Cushing syndrome, the suspected GHRH activity appeared to stimulate the pituitary gland to produce too much growth hormone, leading to acromegaly.
Doctors found signs of Cushing syndrome and acromegaly
The 43-year-old woman sought medical care after two years of symptoms, including enlarged hands and feet, weight gain, skin darkening, and muscle weakness.
She had recently been diagnosed with diabetes and high blood pressure, and her medical history included removal of a carcinoid tumor from the left bronchus, one of the main air passages leading to the lungs, 10 years earlier.
Blood and urine tests showed that her cortisol levels were abnormally high, did not change normally throughout the day, and remained high even after medication that would usually lower cortisol levels. Her 24-hour urinary free cortisol (24-hour UFC), a standard test used to help diagnose Cushing syndrome, was markedly elevated, and her ACTH levels were high. Together, these findings were consistent with ACTH-dependent Cushing syndrome. The 24-hour UFC test measures the amount of cortisol released in urine over a full day and helps estimate how much cortisol the body is producing.
Further tests also showed high levels of insulin-like growth factor 1, or IGF-1, and growth hormone, supporting a diagnosis of acromegaly.
Imaging tests, including a CT scan, revealed a large mass in the chest area, and a biopsy confirmed it was a pulmonary NET. MRI scans showed no pituitary tumor, but revealed diffuse enlargement of the pituitary gland.
Surgery eased symptoms and hormone excess
The woman underwent surgery to remove the pulmonary tumor. Further analyses confirmed it was an atypical pulmonary NET, also called an atypical carcinoid, that produced ACTH. Direct testing for GHRH in the tumor was not available, but the enlarged pituitary gland supported the idea that the lung tumor was driving GHRH-related activity.
After surgery, her cortisol levels dropped quickly. However, because they became too low, she developed adrenal insufficiency — a condition in which the adrenal glands are unable to produce enough steroid hormones, particularly cortisol. As a result, she was prescribed glucocorticoid replacement therapy. Her growth hormone levels also decreased by the fifth day after surgery.
At three months of follow-up, her IGF-1 levels had normalized, and her symptoms had eased. A follow-up pituitary MRI showed complete resolution of pituitary enlargement.
Within nine months of the surgery, cortisol remained suppressed after glucocorticoids were withheld, indicating persistent adrenal insufficiency, so replacement therapy was continued. Because atypical carcinoid tumors can recur or spread, the patient was scheduled for specialized imaging to look for residual or metastatic disease and guide long-term monitoring.
Overall, “this case highlights the importance of recognizing dual hormone–secreting NETs in patients presenting with overlapping endocrine [hormone-related] syndromes, as early detection and complete resection can lead to remission,” the researchers concluded.
