Misc. Disorders

Question 1

Localized asymptomatic skin disorder manifesting with hyperpigmented, velvety plaques typically located in flexural and intertriginous regions
MC in AA

Answer 1

Acanthosis Nigricans

Question 2

cause of Acanthosis Nigricans

Answer 2

unknown
Stimulation of insulin-like growth factor receptors and tyrosine kinase receptors on keratinocytes and fibroblasts

Question 3

8 types of AN

Answer 3

1. obesity
2. malignancy
3. drug induced
4. syndromic
5. acral
6. unilateral
7. benign
8. mixed

Question 4

obesity type of AN is MC linked to what other conditions?

Answer 4

diabetes, insulin resistance, high body mass index (BMI), metabolic syndrome, and PCOS

Question 5

if AN is seen in nonobese patient, be suspicious of?

Answer 5

malignancy

Question 6

malignant AN is MC seen with what cancer?

Answer 6

gastric carcinoma

Question 7

MCC of drug induced AN

Answer 7

niacin

Question 8

different tpyes of syndromic AN

Answer 8

Type A and Type B

• A = Hyperandrogenism, insulin resistant, acanthosis, acromegaly
• B = Autoimmune and Diabetes

Question 9

Symmetric, dark brown hyperpigmented plaques with a velvety, verrucous, or papillomatous appearance
It is typically seen in the neck folds (“dirty neck” appearance) and axillae
The inguinal and inframammary folds, antecubital and popliteal fossae, and elbows and periumbilical region may also be involved

Answer 9

AN

Question 10

More rarer sites for AN?
more suspicious of?

Answer 10

• velvety plaques on the knuckles, palms (“tripe palms”), soles, eyelids, periorally, near mucosal surfaces, or generalized
• more closely related to malignancy
• Oral mucosa and lip lesions have thickening and papillation and usually lack hyperpigmentation