Imiquimod belongs to the class of 1H-imidazo-[4,5-c]
quinolones-drugs originally developed as
nucleoside analogues with the aim of finding new potential
antiviral agents (Harrison et al., 1988). Indeed,
Imiquimod was first released as treatment for
genital warts before its actions against
skin cancer were studied.
Imiquimod is a relatively small sized molecule (Mr = 240.3) and is hydrophobic, allowing it to penetrate the skin epidermal barrier and therefore making it suitable for topical formulations (Gerster et al., 2005).
Imiquimod has shown itself effective against
skin cancers and precancerous lesions, especially
basal cell cancers and
actinic keratosis (Salasche et al., 2002, Beutner et al., 1999). There have been reports of
Imiquimod being used as topical treatment against cutaneous
metastases of
melanoma and some authors have reported its use as first-line
therapy against
melanoma in situ (Smyth et al., 2011, Gagnon, 2011). We report a case of an invasive
malignant melanoma arising de novo at the specific site of application of
Imiquimod (
Aldara cream 5%) for a biopsy-proven superficial BCC. Therefore while
Imiquimod has added to our topical armamentarium against
skin cancer, care must be exercised in prescribing this treatment and it is especially important to follow up patients regularly.