5. Epidemiology
• Incidence is estimated at 1 in 1,000.
• Peak incidence occurs in those aged over
60 years. Is rare in young adults.
• It is uncommon in darker-skinned
patients.
• Males are twice as often affected as
females.
6. • Sunlight and chemical carcinogens have been implicated.
• Trauma, genetic factors and immunocompromised status
have also been associated
• Industrial workers exposed to pitch and tar
• Long-term suppression of the immune system, such as organ
transplant recipients
• Long-term presence of scars, such as from a gasoline burn
• Chronic ulcers
• Presence of particular strains of the wart virus (human
papillomavirus)
• Previous skin cancer
Risk factors
7. Typically rapid growth over a few weeks to months,
followed by a slow spontaneous resolution over 4-6
months (but may take up to 1 year).
• Most occur on sun-exposed areas, e.g the face,
neck, and dorsum of hands and forearms.
• They are usually solitary and begin as firm, round,
skin-coloured or reddish papule
• rapidly progress to dome-shaped nodules with a
smooth shiny surface.
CLINICAL FEATURES
8. • A central crater of ulceration may develop, or a
keratin plug that may project like a horn.
• It leaves a residual scar if not excised.
• Occasionally presents as multiple tumors
9.
10. The most common locations for keratoacanthoma
include:
• Center of the face
• Backs of hands
• Forearms
• Ears
• Scalp
• Lower legs, especially in women
SIGNS AND SYMPTOMS
11. Histopathology
• Cells appear mature and dyskeratosis
• Central plug of keratin
• Surface epithelium at the lateral edge of
tumor appears normal
• Sharply demarcated ,cup shaped buttress of
normal epidermis
• Epithelium exhibiting pseudo-carcinomatous
growth pattern
12. • At the lip of the central crater an acute
angle is formed between the overlying
epithelium and the periphery of the lesion
• The central crater is filled with keratin and
the base of the crater
• Connective tissue exhibits moderate to
marked infiltrate of chronic inflammatory
cells
16. Investigations
Shave biopsy of keratoacanthoma is indistinguishable from
invasive squamous cell carcinoma (SCC).
Therefore, excisional or deep incisional biopsy is
required.
17. • Complete excision is the treatment of
choice for all skin neoplasms thought
to be keratoacanthoma
• Treatments that have produced some
success include
systemic -retinoids (eg isotretinoin),
intraLesional methotrexate, 5-
fluorouracil, bleomycin and
steroids, and topical imiquimod and 5-
fluorouracil
MANAGEMENT
18. • Freezing with liquid nitrogen (cryosurgery), in
which very cold liquid nitrogen is sprayed on
the keratoacanthoma, freezing it and
destroying it in the process.
• In most the lesions are treated before they
reach their maximum size of 2 to 2.5cm
19. • Keratoacanthomas are radiosensitive and
respond well to low doses of radiation.
• Radiation therapy may be useful in selected
patients with large tumors when resection
will result in cosmetic deformity
• for tumor's that have recurred following
attempted excision.
Radiotherapy..
