Case of keratoacanthoma centrifugum marginatum treated with acitretin

Abstract

Keratoacanthoma centrifugum marginatum (KCM) is a rare variant of keratoacanthoma (KA), characterised by a progressively expanding tumour with a lack of spontaneous remission and significant scarring. KCM has been reported previously in less than 50 cases worldwide. We present the case of a large solitary KCM on the right shin of a 71-year-old woman. This was treated successfully with oral acitretin for 16 months with sustained remission at 24 months. Our case provides further supporting evidence for acitretin as a useful treatment for KCM to induce remission, prevent extensive surgery and minimise destructive scarring.

Keywords: dermatology; skin cancer.

Figure 1

(A) Histological examination of first incisional biopsy of lesion on right lower leg at low magnification showing a squamoproliferative lesion. (B) On medium magnification of the first biopsy, there is bland hyperplastic squamous epithelium. (C) Low magnification of second incisional biopsy showed invagination of an atrophic epidermis with abundant keratin tissue. (D) Higher magnification of second biopsy showing features of a regressing keratoacanthoma with complete lack of atypia. H&E, original magnification (A) ×100, (B) ×200, (C) ×100, (D) ×200.

Figure 2

(A) Findings on right shin at 4-month follow-up, showing new verrucous keratotic plaques at periphery of atrophic scar from index lesion. (B) Findings after 6 months of treatment with acitretin. (C) Cribriform scar after 9 months of treatment with acitretin.