Skin nonmelanocytic tumor
Benign (nonmelanotic) epidermal tumors or tumor-like lesions
Large cell acanthoma
Author: Hillary Rose Elwood, M.D.
Last author update: 1 July 2015
Last staff update: 15 April 2021
Copyright: 2002-2023, PathologyOutlines.com, Inc.
PubMed Search: Large cell acanthoma [title] skin
Table of Contents
Definition / general | Case reports | Gross description | Microscopic (histologic) description | Microscopic (histologic) images | Differential diagnosisCite this page: Elwood H. Large cell acanthoma. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/skintumornonmelanocyticlargecellacanthoma.html. 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
- 62 year old man with multiple disseminated large cell acanthomas of the skin associated with HPV6 (J Am Acad Dermatol 2005;53:335)
- Conjunctival lesion with histological features similar to large cell acanthoma (J Cutan Pathol 2010;37:1103)
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
Images hosted on other servers:
Features
Large keratinocytes, hyperkeratosis
Differential diagnosis
- Bowen's disease / squamous cell carcinoma in situ: full thickness keratinocytic atypia with mitoses throughout, often parakeratosis
- Pigmented actinic keratosis: keratinocytic atypia limited to basal layer and lower spinous layer, solar elastosis, occasional parakeratosis
- Solar lentigo: no enlarged keratinocytes
