Researchers have reported the case of a person who developed Cushing’s syndrome due to a tumor in the thymus, which was successfully managed with surgical removal and radiation therapy.
The case report, “Cushing’s syndrome caused by ACTH-producing thymic typical carcinoid with local invasion and regional lymph node metastasis: a case report,” was published in the journal Surgical Case Reports.
Cushing’s syndrome caused by excess adrenocorticotropic hormone (ACTH) usually is a consequence of tumors of the pituitary gland, known as pituitary adenomas. However, 10 to 20 percent of cases of Cushing’s syndrome occur due to non-pituitary tumors, a condition called ectopic ACTH syndrome (EAS).
The most common tumor that causes EAS is small cell lung cancer, followed by thymic carcinoids, which is a very rare tumor that emerges in the thymus. Thymic carcinoids tend to be more aggressive and difficult to treat, with surgery being the only curative treatment for non-metastatic cancer.
Due to the rarity of this disease, the effectiveness of chemotherapy and radiotherapy has not been well-established in literature.
In this case report, researchers discuss the case of a patient with EAS caused by a thymic typical carcinoid tumor that was successfully treated by surgery and followed with radiation.
A 61-year-old woman came to the hospital for general malaise, face swelling, skin pigmentation, insomnia, and high volumes of urine. Laboratory results indicated she had low blood sugar and low levels of potassium.
Further testing showed the patient had elevated levels of serum cortisol and ACTH. A dexamethasone test did not result in a suppression of plasma ACTH levels. Additionally, other pituitary, thyroid, and adrenal hormones were in the normal range. As a result, physicians suspected ectopic ACTH syndrome.
Physicians then sought to identify the location of the ectopic tumor. A computed tomography (CT) scan of the chest showed a tumor of 30 mm in diameter and enlargement of lymph nodes at the anterior mediastinum, which is where the thymus is located.
The patient initially was administered 500 mg/day of metyrapone, a drug used to treat Cushing’s syndrome. This led to a decrease in both ACTH and cortisol levels.
Then, a total thymectomy (removal of the thymus) and lymph node dissection were performed. Further examination revealed the patient had a typical thymic carcinoid tumor and metastasis in the lymph nodes. The final diagnosis was stage IV ACTH-producing thymic carcinoid tumor.
The blood ACTH levels decreased immediately after surgery. Because these patients may experience a suppression of the adrenal glands, due to the long term exposure to ACTH, hydrocortisone was used as replacement therapy during the surgical period and was tapered gradually until four months after surgery.
The patient also received radiation therapy of 60 Gy after surgery to treat regional lymph node metastasis. (Gy is a unit used to measure the total about of radiation the patient is exposed to.) At the 8-month follow-up, the patient showed no signs of Cushing’s syndrome or recurrence of a tumor, indicating successful treatment.
“Although a good prognosis is expected by combined surgery and radiation, relatively high malignancy characteristics are observed compared with typical carcinoids, and strict follow-up is needed,” the investigators concluded.