Acanthosis Nigricans

Last updated 20.09.12

 

 

Definition

-  Hyperpigmented skin lesions seen in many systemic illnesses

 

Features

-  More common in darker skin races

 

Associated S/S

- Symmetrical, hyperpigmented, velvety plaques of skin occuring almost anywhere

-  Common in intertriginous areas of the axilla, groin, back of neck, umbilicus

-  May involve eyes, mucus membranes, nails

-  Often asociated with Archrocordone (skin tags)

-  +/- Pruritic

-  Macula may progress to papules

 

neck

 

Causes

-  Metabolic/Endocrine

-  DM2

-  Cushings Syndrome

-  Obesity

-  > 50% pts > 200% ideal BMI

-  Acromegaly

-  PCOS

-  Hypo/hyperthyroidsm

-  Hereditary

-  Internal malignancy

-  Predates malignancy in 17%

-  Paraneoplastic syndrome

-  Esp adenocarcinoma stomach cancer (90%)

-  25-50% cases lesions seen in mouth, tongue & lips

 

DDx

-  Addisons disease

-  Pellagra

-  Haemochromatosis

 

Ix

-  BSL, OGTT: DM2

-  Malignancy screen

 

Mx

-  Underlying cause

 

 

 

References