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88-Year-Old Male With Lesion On Right Pinna

Can you diagnose this case?

David L. Kaplan, MDSeries Editor

Signs and Symptoms

This 88-year-old man presented for evaluation of a lesion on his right pinna that had grown rapidly over the past several weeks. There was no history of trauma, and the patient absolutely insists that he does not want a biopsy or any surgical procedure.

How would you diagnose this man’s lesion?

Choose one to reveal diagnosis and discussion

Squamous cell carcinoma
Actinic keratosis
Verruca vulgaris
Prurigo nodularis

ANSWER: Keratocanthoma

See the full case at Consultant360

The patient returned 8 weeks later, and the lesion on his ear had regressed spontaneously without any treatment.

Keratoacanthoma is a relatively common low-grade tumor that closely resembles squamous cell carcinoma (SCC). While some authors support classifying keratoacanthoma as a variant of invasive SCC, others believe that keratoacanthoma is a separate entity, based on certain clinical features.1,2

Keratoacanthoma is characterized by rapid growth over a few weeks to months, typically followed by spontaneous resolution over 4 to 6 months in most cases. Because keratoacanthoma may progress to invasive or metastatic carcinoma in rare cases, most authors recommend if not insist on surgical excision to prevent malignant transformation and for medicolegal reasons.

    1. Griffiths RW. Keratoacanthoma observed. Br J Plast Surg. 2004;57(6):485-501.
    2. Ramos LMA, Cardoso SV, Loyola AM, Rocha MA, Durighetto AF Jr. Keratoacanthoma of the inferior lip: review and report of case with spontaneous regression. J Appl Oral Sci. 2009;17(3):262-265.

David L. Kaplan, MD, is a clinical assistant professor of dermatology at the University of Missouri–Kansas City School of Medicine in Kansas City, Missouri, and at the University of Kansas School of Medicine in Kansas City, Kansas. He practices adult and pediatric dermatology in Overland Park, Kansas.