Acanthosis Nigricans: A Skin Marker Of Cancer

What is Acanthosis Nigricans?

Acanthosis nigricans is the cry of the skin for attention! It is a skin disorder characterized by thickening, pigmentation and a fine or rough velvety appearance, particularly over body folds like neck, axilla and groin. The importance of acanthosis.It can be caused by a variety of causes, from obesity to cancer.

People with acanthosis nigricans are known for their resistance to insulin in diabetes.

According to the causes, acanthosis nigricans is divided into two major types:

A. BENIGN ACANTHOSIS NIGRICANS

1. Hereditary benign acanthosis nigricans: This runs in families, but does not usually show any evidence of endocrinological disturbances or internal malignancy.

2. Endocrinal acanthosis nigricans: It is associated with many endocrine problems like acromegaly, addison's disease, Cushing's diseases, insulin resistant diabetes mellitus, hypothyroidism, ovarian hyperthecosis, hepatic cirrhosis,Wilson's disease etc

3. Pseudo acanthosis nigricans: This is a reversible type and usually starts in puberty. It commonly affects dark skinned people and is associated with obesity

4. Drug induced acanthosis nigricans: Nicotinic acid is notorius in causing acanthosis nigricans. Other drugs like stilbostreol, corticosteroids, oral contraceptive pills etc can also cause acanthosis nigricans like lesions.

B. MALIGNANT ACANTHOSIS NIGRICANS(Associated with cancerous growths within).

Internal malignancies (cancers), especially the adenocarcinomas affecting the stomach, lungs etc can cause acanthosis nigricans. Sometimes lymphoma may be the culprit.

Hence it is essential to find out the cause of acanthosis nigricans. Here are a few pointers that may help in differentiating benign from malignant variety of acanthosis nigricans:
How to Differentiate Between the Innocent Benign and the Dangerous Malignant Varieties?

Features	Benign	Malignant
Onset	Birth, childhood or puberty	Adulthood, old age
Distribution
Extent of involvement	Less	Widespread
Distal extremities	Spared	Affected
Mucous membrane involved	Rare	Common-up to 50%
Hair, nail, palms & soles	Rare	Common
Pigmentation	Less, limited to thickened areas	More, extend beyond thickened areas
Skin Thickening	Mild to moderate	Marked
Skin Irritation	Less or nil	More

When to Consult Dermatologist

Consult Dermatologist when the characteristics of acanthosis nigricans are as in the malignant column above.

Salient Points indicating presence of associated internal cancer are:

• Late onset

• Rapid progression

• Severe affection

• Extensive distribution

• Mucous membrane involvement

• More symptoms like irritation and sudden appearance of skin tags

Tips On Dealing With Acanthosis Nigricans

Do's:

1. Differentiate between benign and malignant with the help of a dermatologist

2. Reduction of weight

3. Strict diabetic control

4. Regular aerobic exercises

5. Full investigations including tumor markers, hormonal assay, ultra sound scan, MRI etc

6. Regular medical check up, semi annual

7. Report any sudden changes in morphology

Don'ts

1. Scrub too much, as frequent rubbing will only increase skin thickening and pigmentation

2. Use strong abrasives: tend to irritate the skin more.

Treatment Guidelines of Acanthosis Nigricans

1. Correction of underlying cause

• Removal of tumor

• Correction of endocrine disorder

• Reduction of weight

• Removal of causative drug

2. Dietary supplementation with fish oil containing omega 3 fatty acids have been reported to be

beneficial

3. Cyproheptadine has been found useful in some cases

4. Management of Skin Lesions:

• Topical Retin A

• Salicylic acid application alone or in combination with steroids, alternating with emollient applications to minimize irritation.

• In severe unresponsive cases, systemic retinoids may be given a trial.

An Interesting Case

Curth HO (Archives of Dermatology, Vol 102, 1970) reports a remarkable case of acanthosis nigricans persisting for years even after excising a leiomyoma of stomach,squamous cell carcinoma of bladder and nephrectomy of one kidney for transitional cell carcinoma in a 84 year old man. Then one lesion of adenocarcinoma was found in his colon and removed. Surprise! His long standing acanthosis nigricans disappeared within a few days without any treatment! Moral: To achieve cure you must excise the responsible hormone secreting tumor, not just any tumor!

Disclaimer

Information provided in this article is strictly for educational purposes and is not meant to substitute for the advice provided by your own dermatologist or other medical professionals. You should not use the information contained herein for diagnosing or treating a health problem or disease, or prescribing any medication. Many skin diseases have similar morphology and may resemble one another, though their treatment protocol varies. Hence, self diagnosis and treatment are not advised. In case of doubt always be on the safer side and consult your dermatologist or physician.

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