Nelson syndrome

Last revised by Rohit Sharma on 27 Feb 2018

Citation, DOI, disclosures and article data

Citation:

Verma R, Sharma R, Nelson syndrome. Reference article, Radiopaedia.org (Accessed on 19 Apr 2024) https://doi.org/10.53347/rID-58650

DOI:

https://doi.org/10.53347/rID-58650

Permalink:

https://radiopaedia.org/articles/58650

rID:

58650

Article created:

27 Feb 2018, Rishabh Verma

Disclosures:

At the time the article was created Rishabh Verma had no recorded disclosures.

View Rishabh Verma's current disclosures

Last revised:

27 Feb 2018, Rohit Sharma ◉

Disclosures:

At the time the article was last revised Rohit Sharma had no recorded disclosures.

View Rohit Sharma's current disclosures

Revisions:

2 times, by 2 contributors - see full revision history and disclosures

Systems:

Head & Neck

Sections:

Syndromes

Tags:

cases

Nelson syndrome is a rare disorder observed in patients with Cushing disease that have undergone bilateral adrenalectomy. It involves enlargement of an existing adrenocorticotropic hormone-secreting pituitary tumor, typically an adenoma, after surgical resection of the adrenal glands.

Studies have found a huge variation in the incidence of Nelson syndrome. Incidence rates have varied from 6-47% in adults to 25-66% in pediatric populations undergoing bilateral adrenalectomy ¹. It has been identified that the incidence increases with follow-up time ¹. The presence of high basal adrenocorticotropic hormone (ACTH) is the best predictor for development of Nelson syndrome ¹.

Clinical presentation

The following clinical features may be observed ¹:

skin hyperpigmentation, because melanocyte-stimulating hormone (MSH) and ACTH share the same precursor molecule, proopiomelanocortin (POMC)
headaches, due to displacement of meninges
visual field deficits (e.g. bitemporal hemianopia), due to compression of the optic chiasm
diabetes insipidus, due to compression of posterior pituitary
altered sensation over V1 and V2 sensory areas, due to direct invasion of the cavernous sinus
sudden intracranial hypertension, due to necrosis (usually a late sign)

Pathology

Presumably, Nelson syndrome represents accelerated growth of an existing ACTH-secreting pituitary microadenoma due to the loss of the normal adrenal negative feedback mechanisms.

Microscopic appearance

The tumors stain positive for ACTH and MSH, similar to pituitary adenomas observed in Cushing disease. The tumors are PAS positive.

Radiographic features

MRI is the preferred imaging modality for Nelson syndrome. To establish a diagnosis of Nelson syndrome, a steady growth of the tumor needs to be demonstrated. This can be established with high resolution T1- and T2-weighted images and application of gadolinium contrast, see: pituitary microadenoma.

Treatment and prognosis

Surgical resection of the pituitary adenoma is the gold-standard treatment for Nelson syndrome. If neurosurgery cannot be performed, radiation therapy is the next best management option. Some studies have shown that gamma knife surgery may also be effective ².