Disseminated porokeratosis palmaris and plantaris treated with imiquimod cream to prevent malignancy.

Sir, Disseminated porokeratosis palmaris and plantaris (DPPP), a subtype of porokeratosis Mibelli, is a rare autosomal dominant genodermatosis first described by Guss et al. in 1971 (1). An early review of the literature showed that 7% of 250 patients with porokeratosis subsequently developed skin tumours (2). Squamous cell carcinomas (SCC), Bowen’s disease (BD), and rarely, basal cell carcinomas (BCC) have all been observed on underlying forms of porokeratosis (3). In the past 30 years, only five case reports of metastases derived from SCC on underlying porokeratoses have appeared. BCC have been described only three times in association with porokeratosis (4–6). We report here a 63-year-old man with DPPP, who subsequently developed malignancies. DPPP is present in six members of the patient’s family over four generations, beginning with the patient’s grandmother, and further affecting the patient’s father, brother, daughter and niece (7). The widespread and multifocal nature of BD and SCC in this case, prompted us to examine additional treatment strategies, including topical imiquimod (AldaraH, 3M-Medica, Borken, Germany). To date, standard therapy for porokeratotic diseases comprises symptomatic treatment by application of keratolytics or other topical agents, while skin carcinomas are normally treated by excision. Imiquimod is a topical immune response modifier primarily approved for the management of anogenital warts. Imiquimod was recently approved as a supplementary new drug for the treatment of BCC in parts of Europe and actinic keratosis in the USA. Because porokeratotic lesions have a tendency towards malignancy, we decided to treat our patient with imiquimod.