+++
ACANTHOSIS NIGRICANS (AN) ICD-10: L83
++
Velvety thickening and hyperpigmentation of the skin, seen chiefly on the neck, axilla, groins, and other body folds. Usually symmetric.
May be hyperkeratotic and associated with skin tags.
A cutaneous marker related to heredity, obesity, endocrine disorders (particularly diabetes), medication, and malignancy.
Benign and malignant types.
++
Drug-Induced Acanthosis Nigricans (AN). Can be associated with nicotinic acid, glucocorticoid therapy, oral contraceptives, insulin, protease inhibitors, testosterone, aripiprazole, and growth hormone therapy.
Malignant AN. Rarely can be paraneoplastic, usually gastrointestinal adenocarcinoma but also genitourinary. Oral lesions can occur in 25% to 50% of these patients.
Syndromic AN. Associated with a syndrome, such as hyperinsulinemia, Cushing syndrome, polycystic ovarian syndrome, Crouzon syndrome.
++
AGE OF ONSET More commonly in adulthood.
+++
ETIOLOGY AND PATHOGENESIS
++
Most likely are caused by increased activation of growth factor receptor proteins.
+++
CLINICAL MANIFESTATION
++
Insidious onset, except malignant type, which is rapid. The first visible change is darkening of pigmentation.
++
SKIN LESIONS Darkening of pigmentation (Fig. 5-1). As skin thickens, it appears velvety; skin lines accentuated; surface becomes rugose, mamillated. Often has many skin tags in body folds and neck. Malignant type: Hyperkeratosis and hyperpigmentation more pronounced (Fig. 5-2A). Involvement of oral mucosa and vermilion border of lips (Fig. 5-2B). Hyperkeratosis of the palms/soles, with accentuation of papillary markings, “Tripe hands” (Fig. 5-2C).
++++++
DISTRIBUTION Most commonly, axillae (Fig. 5-1); neck (back, sides), groins (Fig. 5-2A), anogenital, antecubital fossae, knuckles, inframammary, and umbilicus. In malignant type, also periocular, perioral, mammillary, and palms (tripe palms) (Fig. 5-2C).
++
MUCOUS MEMBRANES Oral mucosa: Velvety texture with delicate furrows. Type 5: Mucous membranes and mucocutaneous junctions commonly involved; warty papillomatous perioral thickenings (Fig. 5-2B).
++
Screen for diabetes. Malignancy workup in older patients with ...