Cutaneous horn (cornu cutaneum)

Synonyms
Hauthorn, Keratinhorn, Cornu cutaneum, cutaneous horn, keratin horn
Specialty
Dermatology · Skin tumours
Images
Clinical 2 · Histology 1
In the app
1 flashcards
Last updated
10/2026 · Dr. Pascal Bafteh
Contents
  1. Images (3)
  2. Definition
  3. Classification
  4. Occurrence & epidemiology
  5. Clinical features
  6. Histology
  7. Diagnosis
  8. Differential diagnoses
  9. Keep learning in the app
  10. References (selection)
  11. Cross-references

Images (3)

Cutaneous horn (cornu cutaneum) – clinical photo: a large, several-centimetre cutaneous horn on the ear of an elderly man
a large, several-centimetre cutaneous horn on the ear of an elderly man (Foto: unbekannt (Commons-Nutzer), Wikimedia Commons, CC BY-SA 3.0)unbekannt (Commons-Nutzer), „Cornu cutaneum", CC BY-SA 3.0, via Wikimedia Commons · CC BY-SA 3.0 · Source
Cutaneous horn (cornu cutaneum) – clinical photo: conical yellow-brown to blackish keratin horn with a layered side on the upper helical rim of the ear
conical yellow-brown to blackish keratin horn with a layered side on the upper helical rim of the earKlaus D. Peter, Wiehl, Germany, CC BY 3.0 DE, via Wikimedia Commons · CC BY 3.0 DE · Source
Cutaneous horn (cornu cutaneum) – histology (H&E, overview): massive compact hyper- and parakeratosis forming a tall keratin column above an acanthotic, basaloid epithelial proliferation with a band-like lymphocytic …Histology
histology (H&E, overview): massive compact hyper- and parakeratosis forming a tall keratin column above an acanthotic, basaloid epithelial proliferation with a band-like lymphocytic …Ed Uthman from Houston, TX, USA, „Squamous Carcinoma in Situ with Cutaneous Horn (3884108001)“, CC BY 2.0, via Wikimedia Commons · CC BY 2.0 · Source
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Definition

A cutaneous horn (cornu cutaneum) is a clinical description, not a diagnosis in its own right: a hard, conical projection of compact keratin resembling an animal's horn. What matters is the lesion at the base – it may be benign, premalignant or malignant.

Classification

By the lesion at the base:

  • benign: seborrhoeic keratosis, viral wart, epidermal naevus, molluscum contagiosum, ostraceous psoriasis, hypertrophic lichen planus
  • premalignant or malignant: actinic keratosis, Bowen's disease, keratoacanthoma, squamous cell carcinoma, rarely melanoma

Occurrence & epidemiology

Cutaneous horns occur mainly in older people (peak between 60 and 70 years) and more often in fair skin (phototypes I–II). Men and women are affected about equally often, but the base is more often malignant in men. In two histological series, the proportion of premalignant or malignant base lesions was 38.9% (643 horns) and 58.56% (222 horns).

Clinical features

  • Straight or curved, hard, yellow-brown horn; the side is often terrace-like or oyster shell-like with horizontal ridges, and the base flat, raised or crater-like.
  • Typically more than twice as tall as the width of its base; size from a few millimetres to several centimetres.
  • Usually solitary, mainly on sun-exposed skin (head, ears, backs of the hands, forearms); usually asymptomatic.
  • Clues to squamous cell carcinoma (none is conclusive): pain, large size, induration or redness of the base, a wide base or low height-to-base ratio, lack of terrace formation.

Histology

Compact hyperkeratosis, often with acanthosis. Orderly, horizontally parallel layers of keratin favour a benign lesion; erratic growth suggests a rapidly growing malignant lesion. The base shows the features of the underlying lesion.

Diagnosis

The horn itself is recognised clinically. Because benign and malignant base lesions cannot be reliably distinguished clinically, histological examination of the base of the horn is decisive.

Differential diagnoses

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References (selection)

  1. DermNet: Cutaneous horn
  2. PubMed: A histopathological study of 643 cutaneous horns (PMID 2039721)
  3. PubMed: Cutaneous horn: a retrospective histopathological study of 222 cases (PMID 20520930)

Cross-references

Mentioned in

More skin tumours

Note: This page is intended for medical education and does not replace diagnosis or treatment decisions in individual cases.