Diagnosis

Seborrheic keratosis

A common benign epidermal tumor made up of immature keratinocytes.

Etiology

Cause [4mn]

Pathophysiology [4mn]

  1. Mutation --> A benign clonal proliferation of a immature epidermal keratinocyte

  2. Paraneoplastic syndrome: The sign of Lesser-Trélat is the association of multiple eruptive seborrheic keratoses with internal malignancy (usually gastrointestinal adenocarcinoma)

Risk factors [4mn]

Epidemiology

Prevalence per 100.000 [zwq][zs1][yza][efw]

Epidemiology chart for Prevalence

Symptoms & findings

Symptoms

None listed.

Clinical findings

None listed.

Anamneses

None listed.

Localized findings

Rash
Radiates
CaputCollumThoraxAbdomenGenitalArmBackLower body
Distribution
AsymmetricLocalizedMultiplePhotodistributedSingle
Lesion type
HyperpigmentationMaculePapulePlaque
Lesion configuration
Discoid/nummular
Lesion surface
Verrucous
Color
BrownRed
Associated symptom
BleedingDischargeItchSwelling

Approach

Treatment

  1. Benign tumor --> Treatment is not mandatory

  2. Often removed due to itchy, cosmetic reasons [4mn]

    • Ammonium lactate and alpha hydroxy acids [4ib]

    • Chemical peel (trichloracetic acid)

    • Tazarotene cream 0.1% applied twice daily

    • Eskata: hydrogen peroxide 40% solution

    • Crytherapy (for thinner lesions) [4mn][efw]

    • Curettage

    • Electrocautery

    • Ablative laser surgery

    • Shave biopsy

Differential diagnoses

Acanthosis nigricans, Acrochordon, Acrokeratosis verruciformis of Hopf, Actinic keratosis, Arsenical keratosis, Basal cell carcinoma, Bowenoid papulosis, Condyloma acuminatum, Confluent and Reticulated Papillomatosis, Cutaneous horn, Dermatosis papulosa nigra, Epidermal nevus, Epidermodysplasia verruciformis, Fibroepithelial polyp, Lentigo, Malignant melanoma, Melanocytic nevi, Nevus sebaceus, Pemphigus erythematosus, Premalignant fibroepithelial tumor, Prurigo nodularis, Psoriasis, Squamous cell carcinoma, Stucco keratosis, Verruca vulgaris

References

[1] Greco MJ, Bhutta BS. Seborrheic Keratosis. Updated 2024 May 6: https://www.ncbi.nlm.nih.gov/books/NBK545285/

[2] Yeatman JM, Kilkenny M, Marks R. The prevalence of seborrhoeic keratoses in an Australian population: does exposure to sunlight play a part in their frequency? Br J Dermatol. 1997 Sep;137(3):411-4.

[3] Huang J, Zhang L, Shi L, Wu M, Lv T, Zhang Y, Lai Y, Tu Q, Wang X, Wang H. An epidemiological study on skin tumors of the elderly in a community in Shanghai, China. Sci Rep. 2023 Mar 17;13(1):4441.

[4] Gill D, Dorevitch A, Marks R. The prevalence of seborrheic keratoses in people aged 15 to 30 years: is the term senile keratosis redundant? Arch Dermatol. 2000 Jun;136(6):759-62.

[5] Kwon OS, Hwang EJ, Bae JH, Park HE, Lee JC, Youn JI, Chung JH. Seborrheic keratosis in the Korean males: causative role of sunlight. Photodermatol Photoimmunol Photomed. 2003 Apr;19(2):73-80.

[6] http://emedicine.medscape.com/article/1059477; [Medscape]

[7] Jackson JM, Alexis A, Berman B, Berson DS, Taylor S, Weiss JS. Current Understanding of Seborrheic Keratosis: Prevalence, Etiology, Clinical Presentation, Diagnosis, and Management. J Drugs Dermatol. 2015 Oct;14(10):1119-25.

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