Keratoacanthoma

Question 1

Clinical features

Answer 1

smooth dome shape with keratin filled center, rapid growth and spontaneous resolution (leading to difficult to obtain clinical data d/t spontaneous resolution)

Question 2

KA evolution

Answer 2

1: small, molluscum like papule that rapidly enlarges over weeks. 2: prominent mature nodule remains static for 6 weeks. 3: slow regression over several months leaving atrophy and scarring.

Question 3

best screening test for suspected KA

Answer 3

Excisional bx or saucerization

Question 4

DDx with KA

Answer 4

SCC, nodular BCC, merkel cell, PN, Molluscum. clue is the rapid development and keratin plug

Question 5

Treatment

Answer 5

surgical excision, for larger may need mohs. can do ED&C right after bx but will lead to a scar.

Question 6

pharm tx

Answer 6

5fu or IL MTX. adequate in large lesions with challenging locations. Topical 5FU for weeks for those who are compliant. Oral retinoids for numerous KAs or KA syndrome… cannot get pregnant on it.