Hyperfunctioning unilateral adrenal macronodule in three patients with Cushing's disease: hormonal and imaging characterization

Coexistence of Cushing Disease With a Solitary Adrenocorticotrophic Hormone-Dependent Adrenal Adenoma

Objective

We report a 49-year-old woman who had minimal features of Cushing syndrome and an incidentally discovered adrenal adenoma. She was subsequently diagnosed with pituitary-dependent Cushing syndrome.

Methods

Laboratory and imaging studies including serum cortisol, plasma adrenocorticotrophic hormone (ACTH), high dose dexamethasone test, corticotropin-releasing hormone test, computed tomography (CT) scan, and magnetic resonance imaging were performed.

Results

A 49-year-old woman was admitted for urosepsis. An abdominal CT scan performed during the urosepsis workup showed a 2.7-cm right adrenal adenoma. She denied any abdominal striae or other symptoms. Physical examination showed normal vital signs, minimal facial fullness without central obesity, and striae. Laboratory results were as follows: 24-hour-urine cortisol 294 μg (reference 4.0-50.0), midnight serum cortisol 23.0 μg/dL (reference < 7.5), and plasma ACTH level 39 pg/mL (reference 5-27). A corticotropin-releasing hormone stimulation test showed >20% rise in serum cortisol and >35% rise in ACTH levels. A pituitary magnetic resonance image showed a 5 mm pituitary lesion. The patient underwent transsphenoidal pituitary surgery, which confirmed an ACTH-secreting lesion. Postoperatively, she required hydrocortisone replacement for the next 10 months. A follow-up adrenal CT performed 6 months later showed a decrease in the size of the adrenal adenoma (1.8 cm).

Conclusion

This case highlights the importance of recognizing the coexistence of ACTH-dependent Cushing disease with an adrenal adenoma and partial ACTH dependency of the adrenal adenoma.

Adrenocorticotropic hormone (ACTH) independent Cushing's syndrome due to unilateral adrenocortical hyperplasia: two case reports

Adrenal unilateral macronodular hyperplasia is a rare cause of Cushing's syndrome. We discuss the case of two patients who present Cushing syndrome due to unilateral adrenal hyperplasia. They presented the signs of clinical hypercorticism as well as metabolic, cardiovascular and osteoporotic complications. Both patients presented clinical and laboratory signs of adrenocorticotropic hormone (ACTH)-independent Cushing syndrome with elevated urinary free cortisol (UFC) levels, adrenal computed tomography (CT) scan revealed the appearance of unilateral adrenal adenoma and normal contralateral adrenal gland. Adrenalectomy was performed under laparoscopic surgery; the resected mass was pathologically diagnosed as unilateral nodular adrenal hyperplasia. Unilateral adrenal hyperplasia is a very rare etiology of ACTH-independent Cushing syndrome, often mistaken for adenoma on CT and only pathological examination can confirm the diagnosis.

Adrenal nodules in patients with Cushing's disease: prevalence, clinical significance and follow-up

Adrenal glands in Cushing's disease (CD) range from normal to showing diffuse enlargement in most cases. The finding of nodular lesions has been reported, but information about prevalence and evolution is described in few reports.

AIM

To investigate the prevalence of nodular adrenal glands in patients with CD and assess its evolution after disease remission.

SUBJECTS AND METHODS

We assessed 41 CD patients' abdominal computed tomography (CT) scans obtained during the active phase of the disease and evaluated the dynamics of ACTH and cortisol secretion. CT was repeated after disease remission in patients with adrenal nodules.

RESULTS

Fifteen of 41 patients had nodular and the remaining 26 had normal or enlarged adrenal glands. Patients with nodules were older (45.1 ± 8.8 vs 36.9 ± 12.7 yr; p=0.03) and had longer-standing disease (57.3 ± 56.9 vs 32.9 ± 29.1 months; p=0.05) than patients with normal/enlarged adrenal glands. ACTH (45.4 ± 21.3 vs 70.5 ± 39.1 pg/ml; p=0.04) and urinary free cortisol levels (606.1 ± 512.3 vs 301.0 ± 224.7 μg/day, p=0.01) were significantly lower in patients with adrenal nodules while there were no differences between the groups in terms of dynamic tests results. Post-operative follow-up showed regression or shrinkage of the nodules in 8 out of 10 patients in disease remission.

CONCLUSIONS

We found that adrenal nodular glands are a frequent finding in CD in particular in older patients and in those with a longerstanding disease. Nevertheless, a high percentage of nodules regression or shrinking was evidenced in our series after disease remission.

Imaging functional adrenal disorders

Technological developments in cross-sectional imaging have revolutionized the localization and characterization of functioning adrenal pathology. With effective use of modern imaging, the diagnosis of the cause and nature of functioning adrenal pathology can be reached speedily, accurately and efficiently in the majority of patients. We review the appearance of primary and secondary adrenal pathology, evaluate the diagnostic performance of imaging modalities, highlight newer technical developments, and propose a rational use of these tests in identifying functioning adrenal disease.

Autonomous nodular hyperplasia of the adrenal cortex: tertiary hypercortisolism?

Two cases of Cushing's syndrome are reported in which apparently autonomous adrenal adenomata were associated with the presence of pituitary tumours. In one case the patient was apparently cured by unilateral adrenalectomy, although she was noted to have radiological evidence of an intrasellar tumour; serum cortisol was not suppressed by dexamethasone and ACTH was undetectable. Serum ACTH in the second case was initially 31 ng/l but became undetectable during the course of investigation. Transsphenoidal removal of a corticotroph adenoma did not affect serum cortisol and she proceeded to unilateral adrenalectomy. The pathogenesis of autonomous macronodular hyperplasia is discussed, as well as the options for management.

Endocrine hypertension

All hypertension, in one sense, is endocrine in origin. For the 5% of hypertension that is secondary to a specific mechanism, the majority can be attributed to an endocrinopathy, either too much (Cushing's syndrome, primary aldosteronism, renovascular disease, pheochromocytoma) or too little (renal parenchymal disease). For the 95% of hypertension that remains idiopathic or primary, the multiple environmental factors that act upon a genetic predisposition almost all mediate their effects through hormonal pathways (Figure 1). Since endocrinologists are more likely to deal with the 5% of hypertension that is secondary (Table 1), this review will cover their diagnosis and management in greater detail than the 95% categorized as primary hypertension.