A decrease in the dose of pegvisomant was needed for the treatment of acromegaly after adrenalectomy in a patient with coexisting preclinical Cushing's syndrome

A Rare Case When Acromegaly Meets Cushing Syndrome

Acromegaly is very uncommon, as is non-iatrogenic Cushing syndrome; we discuss a patient who was found to have both a pituitary adenoma causing acromegaly and a cortisol-producing adrenal adenoma causing Cushing syndrome within 1 year. She was a healthy, 44-year-old woman who presented with visual changes and was found to have bitemporal hemianopsia and a 3.3-cm pituitary mass along with central hypogonadism, central hypothyroidism, and suppressed adrenocorticotropin and discrepant cortisol. After transsphenoidal resection she had declining, but persistently elevated, insulin-like growth factor 1 (IGF-1), raising concern for persistent acromegaly. She also was experiencing several cushingoid symptoms and was found to have elevated salivary and urinary cortisol. An abdominal computed tomography scan showed a 3.1-cm adrenal adenoma, and she subsequently underwent adrenalectomy. Following adrenalectomy, her cortisol levels normalized, and her IGF-1, growth hormone, and oral glucose tolerance test showed substantial improvement consistent with previous reports linking hypercortisolism and elevated IGF-1 levels. Combinations of pituitary and adrenal disease are seen in a handful of genetic syndromes; however, her clinical presentation and genetics do not fit with known syndromes. This case describes two rare endocrine tumors in one patient and associated limitations of routine laboratory testing.

Elevated insulin-like growth factor-1 in Cushing's disease

OBJECTIVE

To determine if patients with untreated Cushing's disease have higher serum insulin-like growth factor-1 (IGF-1) compared to matched controls, and if IGF-1 decreases following remission of Cushing's disease.

DESIGN

Retrospective case-control study matching Cushing's disease cases to control patients for adenoma size, age, sex, diabetic and gonadal status, body mass index and serum IGF-1 measured within one year. Paired analysis of pre-operative (untreated) and >3 months post-operative (remission) serum IGF-1 for cases.

PATIENTS AND MEASUREMENTS

All patients were investigated at the Princess Alexandra Hospital Endocrine Unit between 2005 and 2017. Serum IGF-1 was measured in 25 cases and 49 controls, 23 case-control pairs and 13 cases pre- and post-operatively.

RESULTS

Mean serum IGF-1 in cases was significantly higher compared to controls-32 ± 12 nmol/L compared to 25 ± 8 nmol/L, (P = 0.005). The proportion of cases with elevated serum IGF-1 above an age-adjusted reference range was higher compared to 1:1 matched controls (8/23 (35%) vs 1/23 (4%), P = 0.02). In 13 cases in remission post-operatively, serum IGF-1 decreased significantly from 31 (IQR 29-40.5) nmol/L to 23 (IQR 15-28.5) nmol/L, (P < 0.001), despite no difference in the prevalence of pre- vs post-operative pituitary hormone dysfunction (P = 0.47).

CONCLUSION

Patients with untreated Cushing's disease may have elevated IGF-1, which decreases following remission. Mildly elevated IGF-1 in Cushing's disease does not imply pathological growth hormone (GH) excess.

Poorly-controlled acromegaly accompanied by subclinical adrenal Cushing's syndrome after surgery for multiple endocrine tumors

A 48-year-old woman diagnosed with acromegaly 21 years earlier presented at our hospital with a left adrenal tumor. Her medical history included breast cancer, thyroid cancer and an incompletely resected growth hormone (GH)-producing pituitary adenoma. Endocrinological and radiological examinations revealed subclinical adrenal Cushing's syndrome. She subsequently underwent left adrenalectomy, followed by glucocorticoid replacement therapy. Her GH and insulin-like growth factor-1 levels were insufficiently controlled, and pegvisomant was administered in addition to octreotide acetate. Following adrenalectomy, a giant hepatic hemangioma and papillary thyroid carcinoma in the residual right lobe developed, indicating the high risk of tumor development in patients with acromegaly.

Dramatic Improvement of Diabetes Mellitus Following the Treatment of Coexisting Acromegaly and Cushing's Syndrome

Endocrine diseases are frequently accompanied by diabetes mellitus and treatment of an underlying endocrine disease often improves glucose control. The co-occurrence of acromegaly and Cushing's syndrome is extremely rare. We herein describe a patient who showed a dramatic improvement in glucose control following treatment for co-existing acromegaly and Cushing's syndrome. An adrenal mass was incidentally discovered during a routine evaluation of a 56-year-old woman who was subsequently diagnosed with acromegaly and a unilateral cortisol-producing adrenal adenoma. Her blood glucose was poorly controlled despite receiving high-dose insulin therapy. After undergoing adrenalectomy for Cushing's syndrome, her insulin dosage was decreased by almost 50%. The insulin treatment was discontinued following the treatment of acromegaly.