Pituitary tumors that produce too much adrenocorticotropic hormone (ACTH) have been associated with the development of rare tumors on the adrenal glands, called adrenal myelolipomas, for the first time in a case report.
The study, “Case report of a bilateral adrenal myelolipoma associated with Cushing disease,” was published in the journal Medicine.
Myelolipomas, composed of mature fat cells and blood-forming cells, are usually asymptomatic and do not produce hormones. In many cases, these tumors are detected by accident when patients undergo imaging scans for other conditions.
The cause of these tumors is unknown, but due to their benign nature, they do not spread to other parts of the body. However, they can grow up to 34 centimeters (about 13 inches), leading to tissue death and hemorrhage.
Researchers at Soon Chun Hyang University College of Medicine in Seoul, Korea, described the case of a 52-year-old man with myelolipoma possibly caused by an ACTH-secreting pituitary tumor.
During a routine checkup, researchers detected a mass in the patient’s spleen. Further abdominal evaluations identified tissue lesions in both adrenal glands consistent with myelolipoma. Besides the masses, the patient did not show any other Cushing-associated physical characteristics.
However, the patient’s ACTH levels were two times higher than the normal upper limit. Cortisol levels were also increased and unresponsive to low-dose dexamethasone treatment.
No additional lesions were found that could help explain the high ACTH and cortisol levels. But analysis of blood samples collected from the veins draining the pituitary glands revealed the right gland was producing too much ACTH, strongly suggesting Cushing’s disease.
Both the left adrenal gland and pituitary tumor were surgically removed. The samples collected during surgery confirmed the benign nature of the adrenal tumors, and the diagnosis of abnormal, ACTH-positive pituitary gland tissue.
Three days after the surgeries, hormone levels were back to normal. But a follow-up evaluation five months later again showed increased ACTH levels. Cortisol levels, however, were normal.
For the next seven years, the patient was evaluated every six months. During a five-year period, the size of the right adrenal gland was found to have grown. Imaging analysis confirmed the existence of small, new lesions in both pituitary glands.
“This case confers valuable information about the clinical course of adrenal myelolipoma associated with Cushing disease,” the researchers said. It also “supports the notion that ACTH can be associated with the development of bilateral adrenal myelolipomas.”