Misdiagnosis of Underlying Causes of Cushing's syndrome
| About underlying conditions: With a diagnosis of Cushing's syndrome, it is important to consider whether there is an underlying condition causing Cushing's syndrome. These are other medical conditions that may possibly cause Cushing's syndrome. For general information on this form of misdiagnosis, see Underlying Condition Misdiagnosis or Overview of Misdiagnosis |
Underlying conditions list: The list of possible underlying conditions mentioned in various sources for Cushing's syndrome includes:
- Pituitary tumors
- Pituitary adenomas (type of Adenoma) - usually benign ACTH-producing tumors of the pituitary gland; most common in women
- ACTH-producing pituitary tumor
- Lung tumors - more common in men
- Small cell lung cancer (type of Lung cancer)
- Thymoma (type of Thymus Cancer)
- Pancreatic islet cell tumor
- Thyroid medullary carcinoma
- Adrenocortical carcinomas (type of Adrenal Cancer)
- Adrenal gland tumor
- Adrenal adenomas - benign adrenal tumor
- Familial Cushing's Syndrome
- Multiple Endocrine Neoplasia Type I
- Primary Pigmented Micronodular Adrenal Disease
- Carney's complex
- McCune-Albright syndrome
Cushing's syndrome as a complication: Other conditions that might have Cushing's syndrome as a complication might be potential underlying conditions. The list of conditions listing Cushing's syndrome as a complication includes:
Underlying conditions discussion:
Pituitary Adenomas
Pituitary adenomas cause most cases of
Cushing's syndrome. They are benign, or non-cancerous, tumors of the
pituitary gland which secrete increased amounts of ACTH. Most patients
have a single adenoma. This form of the syndrome, known as "Cushing's
disease," affects women five times more frequently than men.
Ectopic ACTH Syndrome
Some benign or malignant (cancerous)
tumors that arise outside the pituitary can produce ACTH. This condition
is known as ectopic ACTH syndrome. Lung tumors cause over 50 percent of
these cases. Men are affected 3 times more frequently than women. The most
common forms of ACTH-producing tumors are oat cell, or small cell lung
cancer, which accounts for about 25 percent of all lung cancer cases, and
carcinoid tumors. Other less common types of tumors that can produce ACTH
are thymomas, pancreatic islet cell tumors, and medullary carcinomas of
the thyroid.
Adrenal Tumors
Sometimes, an abnormality of the adrenal
glands, most often an adrenal tumor, causes Cushing's syndrome. The
average age of onset is about 40 years. Most of these cases involve
non-cancerous tumors of adrenal tissue, called adrenal adenomas, which
release excess cortisol into the blood.
Adrenocortical carcinomas, or adrenal cancers, are the least common cause of Cushing's syndrome. Cancer cells secrete excess levels of several adrenal cortical hormones, including cortisol and adrenal androgens. Adrenocortical carcinomas usually cause very high hormone levels and rapid development of symptoms.
Familial Cushing's Syndrome
Most cases of Cushing's syndrome
are not inherited. Rarely, however, some individuals have special causes
of Cushing's syndrome due to an inherited tendency to develop tumors of
one or more endocrine glands. In Primary Pigmented Micronodular Adrenal
Disease, children or young adults develop small cortisol-producing tumors
of the adrenal glands. In Multiple Endocrine Neoplasia Type I (MEN I),
hormone secreting tumors of the parathyroid glands, pancreas and pituitary
occur. Cushing's syndrome in MEN I may be due to pituitary, ectopic or
adrenal tumors.
1
Exposure to too much
cortisol can occur for different reasons such as long-term use of
glucocorticoid hormones to treat inflammatory illnesses; pituitary
adenomas (benign tumors of the pituitary glands) which secrete increased
amounts of adrenocorticotropic hormone (ACTH); ectopic ACTH syndrome (a
condition in which ACTH is produced by various types of potentially
malignant tumors that occur in different parts of the body); and adrenal
tumors (tumors of the adrenal glands).
2
Footnotes:
1. excerpt from Cushing's Syndrome: NIDDK
2. excerpt from NINDS Cushing's Syndrome Information Page: NINDS
Last revision:
May 26, 2003
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