A man with Cushing’s disease — caused by an adrenocorticotrophic hormone (ACTH)-secreting pituitary adenoma — who later developed metastases in the central nervous system without Cushing’s recurrence, was successfully treated over eight years with radiation and chemotherapy, according to a case report.
The report, “Long-term survival following transformation of an adrenocorticotropic hormone secreting pituitary macroadenoma to a silent corticotroph pituitary carcinoma: Case report,” was published in the journal World Neurosurgery.
Pituitary carcinomas make up only 0.1-0.2% of all pituitary tumors and are characterized by a primary pituitary tumor that metastasizes into cranial, spinal, or systemic locations. Fewer than 200 cases have been reported in the literature.
Most of these carcinomas secrete hormones, with ACTH being the most common. Though the majority of ACTH-secreting carcinomas present with Cushing’s disease, about one-third do not show symptoms of the condition and have normal serum cortisol and ACTH levels. These are called silent corticotroph adenomas and are considered more aggressive.
A research team at the University of Alabama at Birmingham presented the case of a 51-year-old Caucasian man with ACTH-dependent Cushing’s disease. He had undergone an incomplete transsphenoidal (through the nose) resection of an ACTH-secreting pituitary macroadenoma – larger than 10 mm in size – and radiation therapy the year before.
At referral in August 1997, the patient had persistent high cortisol levels and partial hypopituitarism, or pituitary insufficiency. He exhibited Cushing’s symptoms, including facial reddening, moon facies, weight gain above the collarbone, “buffalo hump,” and abdominal stretch marks.
About two years later, the man was weaned off ketoconazole — a medication used to lower cortisol levels — and his cortisol levels had been effectively reduced. He also had no physical manifestations of Cushing’s apart from facial reddening.
In May 2010, the patient reported two episodes of partial seizures, describing two spells of right arm tingling, followed by impaired peripheral vision. Imaging showed a 2.1-by-1-cm mass with an associated cyst within the brain’s right posterior temporal lobe, as well as a 1.8-by-1.2-cm mass at the cervicomedullary junction, which is the region where the brainstem continues as the spinal cord. His right temporal cystic mass was then removed by craniotomy.
A histopathologic analysis was consistent with pituitary carcinoma. Cell morphology was generally similar to the primary pituitary tumor, but cell proliferation was higher. Physical exams showed no recurrence of Cushing’s disease and 24-hour free urinary cortisol was within the normal range.
His cervicomedullary metastasis was treated with radiation therapy in July 2010. He took the oral chemotherapy temozolomide until August 2011, and Avastin (bevacizumab, by Genentech) was administered from September 2010 to November 2012.
At present, the patient continues to undergo annual imaging and laboratory draws. He receives treatment with hydrocortisone, levothyroxine — synthetic thyroid hormone — and testosterone replacement with androgel.
His most recent exam showed no progression over eight years of a small residual right temporal cyst, a residual mass along the pituitary stalk — the connection between the hypothalamus and the pituitary gland — and a small residual mass at the cervicomedullary junction. Lab results continue to show no Cushing’s recurrence.
“Our case is the first to document a patient who initially presented with an endocrinologically active ACTH secreting pituitary adenoma and Cushing’s disease who later developed cranial and spinal metastases without recurrence of Cushing’s disease and transformation to a silent corticotroph pituitary carcinoma,” the scientists wrote.
They added that the report is also the first documenting “8 years of progression free survival in a patient with pituitary carcinoma treated with radiotherapy, [temozolomide] and bevacizumab.”