Cushing’s syndrome can cause blood clots, which might interfere with the pinpointing of ACTH-producing tumors in uncommon places such as the lungs, a case report suggests.
The study, “Pulmonary embolism as the presenting symptom and a confounder in ACTH-secreting bronchial carcinoid,” was published in the journal Endocrinology, Diabetes & Metabolism Case Reports.
The majority of Cushing’s syndrome cases are caused by tumors in the pituitary, a small gland in the brain that produces adrenocorticotropic hormone (ACTH), or the adrenal glands, which produce cortisol and are located over the kidneys. However, about 10% of the cases are due to ectopic tumors, located in organs such as the lungs.
Researchers at the University of California, Davis described the case a 25-year-old woman who had Cushing’s syndrome caused by a tumor in the lungs. The tumor was difficult to locate because of blood clots that obstructed her pulmonary artery.
The patient went to the emergency room because she had shortness of breath when she made any effort and could not walk well because of edema — fluid accumulation — in the lower limbs. The edema had started seven months before; at that time, the patient was also diagnosed with high blood pressure and low potassium, which did not improve with medication.
A physical examination revealed that the woman was obese, and her heartbeat was faster than normal. She also reported that her facial acne had gotten worse, and she had not menstruated in three months. The lab exams showed low potassium levels, diabetes, and high D-dimer, an indicator of blood clots.
Imaging showed blood clots in the lungs that were obstructing the pulmonary artery. The patient had no clots in the lower limbs.
Hormone testing showed high cortisol and normal levels of ACTH, which was odd as they should have been low to compensate for the high cortisol. The doctors performed imaging exams of the pituitary and adrenal glands but found no tumors.
The results of a dexamethasone suppression test, which tests the function of the adrenal glands, and a CRH stimulation test, which examines the function of the pituitary glands, suggested ectopic Cushing’s syndrome.
An imaging test that locates hormone-producing tumors, called Gallium 68 PET/CT Scanning, showed a tumor in the lungs that had previously been mistaken for a blood clot. The lung tumor had migrated to the liver. A biopsy showed that the tumors in the liver produced ACTH, but because of the location of the lung tumor, it was not possible to perform a biopsy.
The patient was not eligible for surgery, so she was treated with mifepristone — a medicine that makes the body less sensitive to cortisol — and octreotide — a treatment that slows down the production of ACTH. She also received an anticoagulant and medication for diabetes and high blood pressure.
The woman started losing weight one month after starting the treatment. By that time, her blood pressure and potassium had improved, and the diabetes was under control. After six months, the levels of ACTH and cortisol were normal.
The investigators concluded that “while no single test is completely sensitive or specific in [ectopic ACTH secretion syndrome], combinations of studies … can substantially enhance diagnostic accuracy. Despite the numerous limitations and often steep costs of biochemical and radiologic studies for this rare disorder, making a timely diagnosis is critical for the optimal clinical outcome.”