Rare pituitary tumor in sinus cavity caused Cushing’s in woman: Report
Mass was found growing outside of usual location at base of brain
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A rare ectopic pituitary adenoma — a pituitary tumor growing outside its usual location — caused Cushing’s disease in a 52-year-old woman in Poland, according to a case report.
The woman had developed Cushing’s symptoms, and laboratory tests confirmed a Cushing’s diagnosis. However, MRI scans did not reveal a tumor within the sella turcica — the small cavity at the base of the brain that houses the pituitary gland, where disease-causing tumors typically form.
Instead, specialized MRI imaging identified a mass in the left sphenoid sinus, an air-filled space behind the nasal passages and below the pituitary gland. Further testing confirmed that this unusual growth was producing excess adrenocorticotropic hormone (ACTH), leading to overproduction of cortisol, the hormone that drives Cushing’s symptoms.
Researchers noted that when lab tests strongly suggest Cushing’s disease but no tumor is visible in the pituitary gland, clinicians should consider the possibility of an ectopic pituitary adenoma.
The study, “Cushing’s disease caused by an ectopic sphenoid pituitary macroadenoma: a major interdisciplinary challenge in everyday clinical practice,” was published in Polish Archives of Internal Medicine.
Distinguishing these rare tumors from others can be challenging
Cushing’s disease occurs when a tumor in the pituitary gland produces excessive ACTH, which stimulates the adrenal glands to release too much cortisol. Persistently high cortisol levels can cause disease symptoms, including weight gain, high blood pressure, easy bruising, and mood changes.
Most ACTH-producing tumors develop within the sella turcica. In rare cases, accounting for about 2% of pituitary adenomas, tumors arise outside this region. These are known as ectopic pituitary adenomas.
Distinguishing these rare tumors from typical Cushing’s disease or from other ACTH-producing tumors elsewhere in the body can be particularly challenging. Diagnosis often requires a careful combination of clinical evaluation, hormone testing, and multiple imaging approaches.
In this report, researchers in Poland describe the case of a woman whose Cushing’s disease was ultimately traced to an ectopic pituitary adenoma that had developed in her sphenoid sinus.
The woman had experienced progressive weight gain of 25 kilograms (about 55 pounds) over two years, along with poorly controlled high blood pressure, easy bruising, and emotional instability. Laboratory tests confirmed Cushing’s disease.
An initial high-resolution MRI, however, did not reveal a tumor within the sella turcica. Instead, a second imaging test using a special contrast dye to highlight abnormal tissue revealed a soft-tissue mass in the left sphenoid sinus, raising suspicion of a pituitary tumor growing outside its normal location.
To determine whether the mass in the sinus was producing ACTH, doctors performed a specialized nuclear imaging scan, called somatostatin receptor scintigraphy, that’s designed to detect hormone-producing tumors. For the test, a small amount of a safe radioactive substance, or tracer, is injected into the bloodstream. The tracer binds to specific receptors abundant on hormone-secreting tumor cells, making them light up on the scan.
The scan showed increased tracer uptake in the sphenoid sinus lesion, supporting the suspicion that it was the source of ACTH excess. Further imaging of the chest, abdomen, and pelvis found no additional tumors.
Fewer than 20 such cases have been documented
The woman underwent minimally invasive surgery through the nasal cavity to remove the tumor. Examination of the removed tissue confirmed it was a pituitary tumor located outside its normal position. Although technically classified as a “silent” type of tumor, meaning it didn’t always secrete ACTH in a typical fashion, it was identified as the source of the hormone imbalance that triggered the patient’s excess cortisol production.
Within months after surgery, her cortisol levels returned to normal and her symptoms resolved.
With this report, we aim to emphasize that among patients with confirmed central ACTH hypersecretion, no evident lesion on sellar MRI, and the presence of an undefined soft-tissue mass in the sphenoid sinus, an ectopic pituitary adenoma should be strongly suspected.
The authors noted that only a small number of similar cases have been reported, with fewer than 20 documented cases. Because standard MRI can miss tumors in atypical locations, the researchers emphasized that unexplained masses near the pituitary region should be carefully evaluated in patients with a confirmed Cushing’s diagnosis.
Treatment, they wrote, should follow established guidelines for Cushing’s disease, including surgical removal to achieve rapid remission and confirm the source of cortisol overproduction.
“With this report, we aim to emphasize that among patients with confirmed central ACTH hypersecretion, no evident lesion on sellar MRI, and the presence of an undefined soft-tissue mass in the sphenoid sinus, an ectopic pituitary adenoma should be strongly suspected,” the researchers wrote.
