Skin nonmelanocytic tumor

Benign (nonmelanotic) epidermal tumors or tumor-like lesions

Large cell acanthoma

Last author update: 1 July 2015
Last staff update: 15 April 2021

Copyright: 2002-2023,, Inc.

PubMed Search: Large cell acanthoma [title] skin

Hillary Rose Elwood, M.D.
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Cite this page: Elwood H. Large cell acanthoma. website. Accessed June 9th, 2023.
Definition / general
  • Benign intraepidermal lesion composed of large keratinocytes
  • Debate as to whether this represents a distinct entity or a reaction pattern within a solar lentigo (Int J Dermatol 2003;42:36)
  • Recent study suggests large cell acanthoma is a solar lentigo with cellular hypertrophy (J Cutan Pathol 2014;41:733)
Case reports
Gross description
  • Light-tan to dark brown, well circumscribed macule or patch
  • Few millimeters to centimeters in diameter
  • Typically on sun exposed skin
  • Clinically resembles a seborrheic or actinic keratosis
Microscopic (histologic) description
  • Atrophic or acanthotic epidermis containing larger than usual keratinocytes (~2x normal epidermal keratinocytes)
  • Usually well demarcated from adjacent epidermis
  • Basal layer may appear hyperpigmented; sometimes conspicuous rete ridges
  • Orthokeratosis; may have hypergranulosis
  • Minimal nuclear pleomorphism
  • Basal mitoses only
Microscopic (histologic) images

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Features Features


Large keratinocytes, hyperkeratosis

Large keratinocytes, hyperkeratosis

Differential diagnosis
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