Rare Chest Tumor Is Cause of Ectopic Cushing’s in Man, 33: Report
Patient saw symptoms ease after surgery to remove cancer tumor
A 33-year-old man with ectopic Cushing’s syndrome saw his symptoms ease after undergoing surgery to remove a rare, slow-growing cancer tumor from his chest.
The carcinoid tumor, a type of neuroendocrine tumor, was the cause of the man’s condition, according to researchers.
“The patient had complete resolution of symptoms after surgery and no recurrence on 2-year follow-up. Further, with earlier diagnostic and timely surgical intervention, the patient survived with no sequelae [other resulting conditions] … 2 years post-surgically,” the team wrote.
His case was described in the report, “Cushing’s syndrome due to atypical carcinoid of the mediastinum,” published in the journal Radiology Case Reports.
No symptoms for patient 2 years after surgery
Cushing’s syndrome is characterized by symptoms associated with hypercortisolism, or high cortisol levels. Cushing’s disease, a common form of the syndrome, is usually caused by benign tumors in the brain’s pituitary gland that lead to the excessive production of adrenocorticotropic hormone (ACTH). In turn, excessive ACTH levels signal the adrenal glands, sitting atop the kidneys, to overproduce cortisol.
In rare cases, referred to as ectopic Cushing’s syndrome, the disease is caused by ACTH-producing tumors found outside the pituitary or adrenal glands. Lung tumors account for about 50% of these cases.
Now, scientists in Vietnam described the rare case of a young man with ectopic Cushing’s syndrome caused by a tumor in the mediastinum — the central compartment in the chest cavity that contains the heart, esophagus, trachea, thymus, and other important structures.
The man was admitted to the hospital with a complaint of pain in his right thigh that had been lasting several days. He recently had been diagnosed with type 2 diabetes, for which he was being treated with metformin.
Physical examination and additional tests revealed he had an abscess in his right thigh. The abscess and the resultant infection were controlled after incision and antibiotic treatment.
Laboratory tests showed he had high blood sugar, or glucose, levels (11.8 millimoles per liter (mmol/L); normal range: 4.1–5.8 mmol/L). The percentage of glycated hemoglobin, that is, the portion of hemoglobin holding blood sugar, was 7.6% (normal range: 4.8–5.9%), indicative of diabetes. He also was diagnosed with hypokalemia, or low blood potassium levels.
Blood sugar levels remained unstable, despite insulin treatment, and potassium levels remained low regardless of potassium replacement treatment. Further laboratory tests to diagnose the cause of hypokalemia, including a 24-hour urinary potassium, suggested kidney potassium loss.
Random serum cortisol was elevated at 1,664 nanomoles per liter (nmol/L; normal range: 120–620 nmol/L). ACTH was also high, at 854 picograms per milliliter (pg/mL; normal range: 7.2–63 pg/mL).
Low and high-dose dexamethasone suppression tests, which are used to screen for hypercortisolism and determine the source of excess cortisol, were both ineffective at lowering cortisol levels, suggesting the presence of an ectopic ACTH-producing tumor.
MRI scans confirmed he had no pituitary tumor, and further CT scans identified a mass in the mediastinum. There were no signs of lymph node involvement or tumor spreading. The mass was completely removed surgically and was found to be an intermediate-grade tumor.
Tumor cells were positive for Synaptophysin, CD56, and Chromogranin, which are markers of neuroendocrine tumors (NETs) — rare tumors that affect the cells that release hormones into the bloodstream (neuroendocrine cells).
The patient had complete resolution of symptoms after surgery and no recurrence on 2-year follow-up.
One day after surgery, ACTH and cortisol levels returned to normal, as did potassium levels, without further treatment. Two months after surgery, glucose levels were normal without insulin or oral diabetic medication.
The surgery’s effectiveness in treating Cushing’s was confirmed at a two-year follow-up, with the patient presenting complete disease resolution, with normal ACTH, cortisol, potassium, and glucose levels, and showing no signs of tumor recurrence.
“We presented a case of a young male who presented with nonspecific Cushing’s symptoms, but was experiencing several complications [caused] by excessive glucocorticoids. Because of earlier recognition and complete resection of malignancies, this patient had a better outcome and survival,” the researchers concluded.
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