Case Description
A 21-year old male presented in our Department due to an asymptomatic nodule in the proximal fifth digit of the right hand, that had first appeared 3 months prior to the referral. The lesion rapidly progressed in size during the first 4 weeks and afterwards remained stable. The clinical examination revealed a firm skin-coloured nodule, of approximately 1.8 x 1.8 cm in size, with a central non-removable keratinous plug (Figure 1A). The clinical diagnosis of keratoacanthoma was made, and a biopsy was recommended for diagnosis confirmation. The patient strongly refused the diagnostic biopsy and insisted on a non surgical treatment. We therefore suggested a regimen of topical imiquimod 5% cream under occlusion, for 5 consecutive days per week, over a period of 4 weeks. 2 weeks after treatment initiation, a prominent local inflammatory reaction could be documented, resulting in crust formation and erosion (Figure 1B). 4 weeks after the completion of treatment, the lesion was markedly flattened, until complete resolution was achieved (Figure 1C).
Keratoacanthomas (KA) are epithelial tumours that present as rapidly evolving nodules with a central hyperkeratotic plug, and occasionally show signs of spontaneous regression [1]. The treatment of choice for KAs is surgical excision, as it provides the advantage of complete tumour removal in a short period of time [1-2]. However, conservative therapeutic strategies are also to be considered, especially when it comes to the management of KAs in visible areas with a probability of cosmetic disfiguration, or when it comes to treating patients with multiple KAs [2].
Keywords: Keratoacanthomas, imiquimod cream, epithelial tumour