Keratoacanthoma



Keratoacanthoma


David Cassarino, MD, PhD










Clinical photograph shows a tumor with raised borders and a central, crateriform keratin-filled defect, consistent with a keratoacanthoma. (Courtesy S. Yashar, MD.)






Scanning magnification of a keratoacanthoma shows an endophytic-appearing atypical squamous proliferation with prominent, central keratin-filled cavities image.


TERMINOLOGY


Abbreviations



  • Keratoacanthoma (KA)


Synonyms



  • Crateriform ulcer


  • Self-healing squamous cell carcinoma


Definitions



  • Very well-differentiated form of cutaneous squamous cell carcinoma (SCC), which often spontaneously regresses


ETIOLOGY/PATHOGENESIS


Environmental Exposure



  • Similar to other forms of SCC, typically related to chronic solar (UV) damage



    • Vast majority of lesions occur in sun-damaged skin of older adults


    • Regression is thought to be due to immune-mediated destruction of the squamous cells


CLINICAL ISSUES


Epidemiology



  • Incidence



    • Relatively common, may represent up to 25% of cases of cutaneous SCC


  • Age



    • Older adults, mean age is mid 60s


  • Gender



    • More common in males


  • Ethnicity



    • Most common in Caucasians


Site



  • Head and neck most common, followed by arms, legs


Presentation



  • Rapidly growing nodular lesion



    • Often dome-shaped with central keratinous plug


    • May reach large size, up to 10 cm (giant keratoacanthoma)


Treatment



  • Options, risks, complications



    • Surgical excision is mainstay of treatment although observation may be acceptable in many cases


  • Surgical approaches



    • Complete excision is curative but likely not necessary in most cases due to spontaneous regression


    • Patients with giant KAs, subungual KAs, and immunosuppressed patients should have complete excision, as lesions may not regress in these patients


Prognosis



  • Excellent; vast majority of cases spontaneously regress


  • Rare case reports of metastatic KA, but most of these are in giant or subungual KAs or immunosuppressed patients


MACROSCOPIC FEATURES


General Features



  • Typically large, scaly lesions with central keratinous crater


MICROSCOPIC PATHOLOGY


Histologic Features

Jul 8, 2016 | Posted by in PATHOLOGY & LABORATORY MEDICINE | Comments Off on Keratoacanthoma
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