Large cell acanthoma (LCA) also called Degos acanthoma is a benign tumor of the sebaceous gland that can often be confused with seborrhoeic keratosis or melanoma. Large cell acanthoma may be a variant of seborrhoeic keratosis.
They typically occur in middle aged or older adults especially those with light skin complexion.

Cause and Risk factors

The exact cause for LCA is unknown but risk factors associated with LCA development include:

  • UV light exposure, Tanning beds, Fair complexion.
  • Human papilloma virus infection (especially HPV 6) have also been implicated.

Symptoms and Clinical Presentation

Large cell acanthoma are usually present on sun exposed areas like the face, trunk and extremities. These skin lesions can resemble melanoma, seborrhoeic keratosis (SK) and are often biopsied to confirm the histology.

They appear as single to multiple slightly elevated skin lesions often < 1 cm but can be up to 2 cm in diameter. LCA can be dome in shape or nodular.

The color or LCA varies from pinkish brown but typically blood red and shiny appearance. The wafer-like crusty, scale may be found around the edges of the lesion with a moist nikolsky’s sign appearance when the scales are removed.


  • Clinical examination, dermatoscopy and biopsy. Diagnosis rarely made before biopsy.
  • Dermatoscopy – may show blood vessels lined up in string

Treatment of Dermatofibroma

These lesions are often left alone. Most treatment are for cosmetic reasons via surgical excision.