Nelson tumor

Nelson Tumor

Description, Causes and Risk Factors:

It is a kind of pituitary tumor. The pituitary gland is part of our endocrine system, which consists of glands that produce hormones that regulate processes throughout our body. Besides the pituitary gland, the endocrine system includes the thyroid gland, parathyroid glands, adrenal glands, pancreas, ovaries and testicles.

Most pituitary tumors are benign. Up to 20% of people have pituitary tumors. However, many of these tumors do not cause symptoms and are never diagnosed during the person's lifetime.

Nelson's syndrome is an iatrogenic condition. Nelson syndrome is a rare clinical manifestation of an enlarging pituitary adenoma that can occur following bilateral adrenalectomy performed in the treatment of Cushing disease (CD).

In the Nelson syndrome, rapid growth of an adrenocorticotropic hormone-secreting following bilateral adrenalectomy causes extreme elevation of melanocortin levels and hyperpigmentation. The Nelson syndrome is a human model in which temporal associations among body weight, skin pigmentation, and high circulating levels of melanocortins might be observed. Nelson's tumor cells differ to some degree from those from Cushing's tumors. Recent research underscores the intriguing possibility that somatic mutations in the glucocorticoid receptor gene might contribute to its pathogenesis. The incidence of Nelson's syndrome after adrenalectomy is still a matter of dispute, in part explained by lack in uniformity of definition of the syndrome. Postoperative radiotherapy is indicated in patients with residual tumor or extracellular extension. Recent reports claim benefit from long-acting somatostatin analogues, although long-term success remains to be assessed. Notwithstanding improved treatment, Nelson's syndrome shares with Cushing's disease the inevitable tendency to recur. Therefore, life-long management of these patients is mandatory.

Risk Factors:

    Nelson syndrome occurred formerly as a result of bilateral adrenalectomy for Cushing's disease. Resulting in absent negative feedback of cortisol on the pituitary adenoma, with expansion of the pituitary adenoma with headache, bitemporal hemianopia and panhypopit eventually.

  • Hereditary disease like multiple endocrine neoplasia type 1, carney complex, isolated familial acromegaly.


Common Symptoms Include:

    Nausea or vomiting.

  • Forehead headaches.

  • Loss of body hairs.

  • Sweating.

  • Easy bruising.

  • Change in sense of smell.

  • Depression.

  • Unexplained weight loss.

  • Sexual dysfunction.

  • Change in menses or early menopause.

  • Trouble sleeping.

  • Frequent bowel movements.

  • Confusion.

  • Dizziness.

  • Seizure.

Key Symptoms:

  • A key finding is darkening of skin color and increased pigmentation of nevi.

  • Because ACTH-secreting tumors are typically aggressive and invasive, patients may develop large tumors resulting in visual loss, pituitary failure and headache.


All pituitary masses should have screening basal hormone measurements, including:

  • Prolactin.

  • TSH, FT4.

  • ACTH, AM cortisol, midnight salivary cortisol.

  • LH, FSH, estradiol or testosterone.

  • Insulin-like growth factor-1 (IGF-1).

Dynamic stimulation/suppression testing may be useful in select cases to further evaluate pituitary reserve and/or for pituitary hyperfunction.

    Dexamethasone suppression testing.

  • Oral glucose GH suppression test.

  • GHRH, L-dopa, arginine.

  • CRH stimulation.

  • Metyrapone.

  • TRH stimulation.

  • GnRH stimulation.

  • Insulin-induced hypoglycemia.

Other Common Tests Include:

    Visual field exam.

  • Neurologic exam.

  • MRI and CT scan.

  • Blood Test.

  • Urine Test.

  • Venous sampling.

  • Immunohistochemistry study.


Treatment Options Include:


  • Pharmacotherapy. Most useful in prolactinomas, alone or with other intervention. May be used in certain other functioning tumors as adjunctive therapy along with surgical and/or radiotherapy.

  • Surgery. Useful when medical or radiotherapy fails. Surgery provides prompt relief from excess hormone secretion and mass effect.

  • Radiation Therapy. Reserved for patients with larger tumors and/or persistent hormonal hyperfunction despite surgical intervention (Conventional radiotherapy, Gamma knife radiosurgery).

Today, with greater awareness of NS and with the availability of modern neuroimaging and immunoassays, tumor progression can be detected much earlier and thus at a smaller lesion size. Surgery remains the primary mode of therapy. Radiotherapeutic protocols offer additional options for treatment. Although not widely accepted, some pharmacotherapeutic measures can also be offered to patients with resistant lesions. If untreated, NS adenomas often become markedly aggressive and may cause death in some patients, usually through brain invasion.

Disclaimer: The information provided here is just informative purpose. The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition.

DISCLAIMER: This information should not substitute for seeking responsible, professional medical care.


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