Imaging abnormality can make diagnosing Cushing’s disease harder

Fluid buildup in structure housing pituitary gland affects imaging tests

Marisa Wexler, MS avatar

by Marisa Wexler, MS |

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An imaging abnormality that makes it harder for clinicians to visualize the brain’s pituitary gland can complicate efforts to diagnose and manage Cushing’s disease, a recent report highlights.

The abnormality affects the bony compartment that houses the pituitary gland, making “visual diagnosis of pituitary adenoma [benign tumors] even more challenging in clinical practice,” its scientists wrote.

The report, “Cushing’s Disease Associated With Partially Empty Sella Turcica Syndrome: A Case Report,” was published in the journal Cureus.

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Cushing’s disease is caused by a tumor in the pituitary gland, leading to excessive production of a signaling molecule called adrenocorticotropic hormone (ACTH). High levels of ACTH spur the production of cortisol, a stress hormone, and these high cortisol levels ultimately drive most disease symptoms.

The pituitary gland is located in a bony compartment called the sella turcica. Empty sella turcica syndrome, or EST, is a condition where this compartment appears to be empty on imaging tests. Despite the name, the compartment is not actually empty. Instead, what generally happens in EST is that the compartment fills with fluid, causing the pituitary gland to become flattened against one of its sides and therefore harder to see on imaging tests.

EST doesn’t necessarily cause problems. In fact, it’s estimated that up to 1 in 5 people have this imaging abnormality. But since EST by definition makes it harder for doctors to see the pituitary gland on imaging tests, it can make diagnosing Cushing’s and managing the disease more challenging.

A team of U.S. researchers described the case of a 47-year-old man who came to a hospital’s emergency room complaining of generalized muscle weakness. Muscle weakness had been gradually worsening in the weeks prior to his arrival at the hospital, and over the past few days, he had trouble walking. He also reported substantial unintended weight loss in the past four months, of about 40 pounds, and a physical examination revealed areas of unusually darkened skin.

Laboratory tests, including measures of cortisol in the saliva and urine, and a dexamethasone test, confirmed a Cushing’s disease diagnosis. Imaging of the patient’s brain also revealed partial EST, as the pituitary gland was partly obscured, though a pituitary mass was visible toward the base of the sella turcica compartment.

The patient underwent surgery to remove the pituitary tumor and treat his Cushing’s.

A few days after the surgery, the man returned to the emergency room because fluid was draining from his nose, and he had a worsening headache.

Tests revealed cerebrospinal fluid (CSF) leakage, which happens when the liquid that normally surrounds the brain and spinal cord leaks out. Clinicians initially attempted to drain the fluid, but this was not successful. Ultimately, surgery was required to repair the leak.

At follow-up a few months later found no further signs of CSF leakage, and laboratory tests were back in normal ranges.

Since EST is generally caused by the buildup of fluid around the pituitary gland, the scientists speculated that this imaging abnormality might be a risk factor for complications like CSF leakage after surgery, noting a need for further research. More generally, they said this case highlights how EST can cause complications with Cushing’s.

“This case reflects the rare association of EST syndrome and Cushing’s disease, suggesting the increased risk of postoperative complications in this setting and the diagnostic challenge that EST syndrome imposes,” the team wrote.