Islets of Hope for persons with diabetes
Article Source: Edited for content by Lahle Wolfe, from Wikipedia.com
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Information links to possible causes of AN
Hemochromatosis (iron overload, or "bronze diabetes)
The benefits of anaerobic activity for diabetics (strength training)
Complementary Approaches for Fitness & Stress Management
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External links to information about AN and possible causes
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What is acanthosis nigricans?
What is acanthosis nigricans?
Acanthosis nigricans (AN) is a brown to black, poorly defined, velvety hyperpigmentation of the skin, usually present in the posterior and lateral folds of the neck, the axilla, groin, umbilicus, and other areas. It is often seen in persons with type 2 diabetes, insulin resistance, and polycystic ovarian syndrome (PCOS). Following a healthy diet (to avoid insulin spikes) and keeping blood glucose levels in check may help improve the appearance of, or prevent AN from developing.
Synonyms and related keywords
AN, insulin resistance, insulin-resistant state, malignancy, malignant AN, malignant acanthosis nigricans, acrochordons, malignant acrochordons, hyperandrogenemia, HAIR-AN syndrome, dermatosis, Wilms tumor, darkening and thickening of the skin, obesity, leukonychia, hyperkeratosis, obesity-associated AN, syndromic AN, polycystic ovaries, hirsutism, clitoral hypertrophy, diabetes mellitus, ovarian hyperandrogenism, systemic lupus erythematosus, scleroderma, Sjögren syndrome, Hashimoto thyroiditis, acral AN, acral acanthotic anomaly, nevoid AN, genodermatosis, gastric adenocarcinoma, gastric neoplasm
AN can be both a benign condition (merely a visual evidence of another underlying medical problem) or a malignant condition.
Benign AN can be seen at birth, in children, and adults. It is seen equally in men and women but is more common in persons with darker skin (African Americans and Hispanic persons have a higher rate of AN than do Caucasian persons) and the degree of affectation may parallel the severity of insulin resistance.
Malignant AN is most often seen in elderly persons and patient survival rate varies, with an average of approximately 2 years after diagnosis.
Medical conditions associated with benign AN
The most common cause of benign AN is insulin resistance, usually from type 2 diabetes mellitus, or polycystic ovarian syndrome (PCOS). AN can also be seen with Hashimoto's Thyroiditis, Addison's disease, and hemochromatosis (iron overload, or "bronze" diabetes). Sometimes, AN is a hereditary condtion.
There is also a form of AN that is malignant (cancerous). Malignant AN is clinically indistinguishable from the benign forms; however, one must be more suspicious if the lesions arise rapidly, are more extensive, are symptomatic, or are in atypical locations.
Currently, 8 types of AN have been identified:
Acral AN (acral acanthotic anomaly) occurs in patients who are in otherwise good health. Acral AN is most common in dark-skinned individuals, especially those of African American descent. The hyperkeratotic velvety lesions are most prominent over the dorsal aspects of the hands and feet.
Drug-induced AN, although uncommon, may be induced by several medications, including nicotinic acid, insulin, pituitary extract, systemic corticosteroids, and diethylstilbestrol. And, rarely, triazinate, oral contraceptives, fusidic acid, and methyltestosterone also have been associated with AN. The lesions of drug-induced AN may regress following the discontinuation of the offending medication.
Familial AN is a rare genodermatosis that seems to be genetically transmitted. The lesions typically begin during early childhood but may manifest at any age and the condition often progresses until puberty, at which time it stabilizes or regresses.
Malignant AN is associated with internal malignancy, is the most worrisome of the variants of AN because the underlying neoplasm is often an aggressive cancer. (See below for more detail.)
Mixed-type AN refers to those situations in which a patient with one of the above types of AN develops new lesions of a different etiology. An example of this would be an overweight patient with obesity-associated AN who subsequently develops malignant AN.
Obesity-associated AN, once labeled pseudo-AN, is the most common type of AN. Lesions may appear at any age but are more common in adulthood. The dermatosis is weight dependent, and lesions may completely regress with weight reduction. Insulin resistance is often present in these patients; however, it is not universal.
Syndromic AN is the name given to AN that is associated with a syndrome. In addition to the widely recognized association of AN with insulin resistance, AN has been associated with numerous syndromes. The type A syndrome and type B syndrome are special examples.
Unilateral AN, sometimes referred to as nevoid AN, is believed to be inherited as an autosomal dominant trait. Lesions are unilateral in distribution and may become evident during infancy, childhood, or adulthood. Lesions tend to enlarge gradually before stabilizing or regressing.
This type of AN is associated with internal malignancy, is the most worrisome of the variants of AN because the underlying neoplasm is often an aggressive cancer. AN has been reported with many kinds of cancer, but, by far, the most common underlying malignancy is an adenocarcinoma (cancer) of gastrointestinal origin, usually a gastric adenocarcinoma. In an early study of 191 patients with malignant AN, 92% had an underlying abdominal cancer, of which 69% were gastric. Another study reported 94 cases of malignant AN, of which 61% were secondary to a gastric neoplasm.
In 25-50% of cases of malignant AN, the mouth is involved. The tongue and the lips most commonly are affected with elongation of the filiform papillae on the dorsal and lateral surfaces of the tongue and multiple papillary lesions appearing on the commissures of the lips. Oral lesions of AN seldom are pigmented.
Tests that may help determine the cause of AN
Your doctor may perform some of the following tests to determine the cause of AN:
Other problems to be considered
Complications vary depending on the cause of AN. Appearance of AN during childhood usually is associated with a benign condition, and there is usually little cause for medical concern. Adult onset AN is more worrisome, and both diabetes or an underlying malignancy should be ruled out. However, most cases of adult onset AN are benign and often are associated with insulin resistance or type 2 diabetes.
Prognosis for Persons with Malignant AN
The prognosis for patients with malignant AN is often poor. The associated malignancy frequently is advanced, and the average survival of these patients is approximately 2 years.
Page Updated 03/23/2006