Ectopic pituitary tumor is culprit in rare Cushing’s case

Surgery was effective treatment, but woman may need more radiation therapy

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by Andrea Lobo |

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A woman developed Cushing’s syndrome as a result of a rare pituitary tumor in the clivus region — a bone at the base of the skull — that produced excess levels of the adrenocorticotropic hormone (ACTH), a case study from China reports.

This is a very rare case of Cushing’s syndrome, with only six other similar cases reported in the literature. The findings show surgery is an effective treatment for easing the clinical manifestations of Cushing’s in these cases, but additional radiation therapy may be needed if the tumor invades bone tissue.

The case report, “Cushing syndrome caused by an ectopic ACTH-producing pituitary adenoma of the clivus region: A rare case report and literature review,” was published in the journal Medicine.

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Cushing’s syndrome is an umbrella term of disorders in which there is too much of the hormone cortisol in the body; this is known as hypercortisolism.

The presence of benign tumors (adenomas) in the pituitary gland are the most common cause of Cushing’s, accounting for approximately 70% of all cases. These patients, who have a disease form called Cushing’s disease, have tumors that produce the ACTH hormone in excess, which then  stimulates the adrenal glands, sitting atop the kidneys, to produce and release cortisol into the bloodstream.

In some cases, however, the excess of ACTH can come from ectopic pituitary tumors, which are pituitary adenomas located outside the sellar area (the tiny space in the skull where the pituitary gland sits) that have no direct connection with normal pituitary tissue.

A very rare case of Cushing’s syndrome

Now, a team of researchers in China described the case of a woman who developed a very rare case of Cushing’s syndrome associated with an ectopic ACTH-secreting pituitary adenoma located in the clivus region, a bone at the base of the skull, close to the spine.

The 53-year-old woman went to the hospital after experiencing two years of  headaches and dizziness, which had worsened in the past week. She had high blood pressure, which she reported to be under control with medication.

A physical examination revealed a classical Cushing’s-like appearance, including a moon face, fat accumulation in the back, shoulders, and abdomen, and high blood pressure.

ACTH levels also were high and a high-dose dexamethasone suppression test reduced cortisol levels by less than 50%, suggesting ectopic ACTH-dependent Cushing’s. Dexamethasone is a medication that normally lowers cortisol levels by suppressing ACTH production.

A CT scan revealed a soft tissue mass measuring about 3 centimeters in diameter in the clivus region, but the pituitary gland was normal. The tumor was removed via transsphenoidal endoscopy — a minimally invasive surgery that removes tumors in the pituitary region through the nose.

Diagnosis: EAPA

Based on the patient’s medical history, clinical and laboratory symptoms, and the characteristics of the tumor cells, she was diagnosed with ectopic ACTH-producing pituitary adenoma (EAPA).

Two months after the surgery, her Cushing-like features had improved, and her blood pressure was normal. Likewise, her blood cortisol and ACTH levels returned to normal levels six months after the surgery. No signs of tumor recurrence were detected.

“The clival EAPA is extremely unwonted [unusual], and only 6 other cases apart from ours have been reported in literature so far,” the researchers wrote.

The average age of patients with these tumors was 48 years, and the majority (six of seven) were women. Notably, only two patients, including the women described in this case report, developed overt symptoms of Cushing’s.

Removal of the tumor

“The gold standard for the treatment of [Cushing’s] caused by EAPA was the surgical removal of [the tumor], which was essential to achieve remission and histological confirmation of the disease,” the researchers wrote.

The most common surgical procedure used was transsphenoidal tumor resection (in four patients). Craniotomy — a procedure where a piece of the skull is removed to expose part of the brain — and maxillary osteotomy, which involves cutting the upper jaw, were used in one patient each.

There was no consensus on the best approach, and according to the researchers, the choice “was believed to be based on the condition of the adenoma, as well as the general condition of the patient and the experience of the surgeon.”

Three patients underwent radiotherapy after the surgery, based on the invasion of the surrounding bone tissue. All patients experienced effective relief of their symptoms after the surgery.

“Due to the rarity of this disorder, an accurate preoperative diagnosis of EAPA in the slope area is extremely challenging for the clinician or radiologist,” the researchers wrote.

“Further cases may be necessary to summarize the clinical features of such lesions and to develop optimal treatment strategies,” they added.