Seborrheic keratosis

Background

• In itself benign, no treatment necessary

Clinical Features

Multiple seborrheic keratoses on the dorsum of a patient with Leser–Trélat sign.

• Light tan to black rash
• Round, oval
• Flat to elevated, verrucous
• Velvety, waxy, "stuck-on" appearance

Leser-Trelat Sign

Seborrheic keratosis

• Requires follow up for malignancy workup
• New onset diffuse lesions
• Tends towards trunk by may involve:
  • Neck
  • Axilla
  • Groin
• Associated with other paraneoplastic derm signs:
  • Malignant acanthosis nigricans (more classically associated with internal malignancy)
  • Florid cutaneous papillomatosis
  • Eruptive capillary angiomas

Differential Diagnosis

Dark raised skin lesions

• Acanthosis nigricans
• Kaposi's sarcoma
• Melanoma
• Nevus
• Seborrheic keratosis

See Also

• General approach to rashes