Thyroid cancer causes Cushing’s syndrome in man in his 30s
Case highlights Cushing’s as a first symptom of rare metastatic thyroid cancer
A rare and aggressive form of thyroid cancer caused Cushing’s syndrome in a man in his 30s, according to a case report.
“This case underscores the complexity of diagnosing and managing ectopic Cushing’s syndrome, particularly when it is secondary to a rare malignancy,” researchers wrote.
The case report, “Malignant thyroid neoplasm with ectopic Cushing’s syndrome,” was published in BMJ Case Reports.
Cushing’s syndrome is a broad term referring to any disease driven by excessively high levels of the hormone cortisol. Cushing’s disease is a specific form of the syndrome caused by a tumor in the brain’s pituitary gland. In Cushing’s disease, the pituitary tumor produces and releases high levels of adrenocorticotropic hormone (ACTH), a signaling molecule that prompts the adrenal glands, located above the kidneys, to make too much cortisol.
Most ACTH-producing tumors occur in pituitary
The pituitary gland is normally responsible for making ACTH, so most ACTH-producing tumors occur in the pituitary. More rarely, however, tumors in other parts of the body can produce ACTH and cause Cushing’s. This is referred to as ectopic Cushing’s syndrome.
In the report, scientists in India reported the case of a man who developed ectopic Cushing’s due to a tumor in the thyroid gland, which is located at the bottom of the throat.
The patient had recently been diagnosed with diabetes and high blood pressure, and in the previous year, he had gained more than 30 pounds that he was unable to lose despite lifestyle changes. He also reported easy bruising, weakness, and purplish stretch marks along his abdomen and arms, which, along with weight gain, are telltale symptoms of Cushing’s.
The month before he was diagnosed, the man noticed a painless lump in his throat, which prompted him to seek medical attention. Testing showed he had a tumor in his thyroid gland, which was confirmed to be medullary thyroid carcinoma (MTC), a rare type of thyroid cancer.
Additional tests revealed the presence of high levels of ACTH and cortisol in his blood, but failed to detect any pituitary abnormalities. These tests collectively led the man to be diagnosed with ectopic Cushing’s syndrome secondary to MTC.
Since his Cushing’s syndrome was not responding well to medications and was causing him health problems, the man initially underwent surgery to remove his adrenal glands.
Then, he had surgery to remove his thyroid gland, including the disease-driving tumor. Analysis of the removed tissue confirmed the diagnosis of MTC and the presence of ACTH in the tumor.
Following surgery, his ACTH and cortisol levels dropped, and he no longer showed signs of diabetes or high blood pressure. However, follow-up tests showed remnants of cancer in his body. The man is currently undergoing radiation therapy with the goal of eliminating the residual cancer.
“Cushing’s syndrome resulting from ectopic ACTH secretion is a rare but serious complication of metastatic MTC. Clinicians should be aware that Cushing’s syndrome can occasionally be the initial presenting feature of metastatic MTC,” the researchers wrote.
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