Compound lesion of a basal cell carcinoma and a malignant melanoma: Is there a common genetic origin?

A compound or collision tumor is a rare occurrence in dermatological findings [1]. The coincidence of malignant melanoma (MM) and basal cell carcinoma (BCC) within the same lesion have only been described in few cases in the literature [2–5]. However, until now the pathogenesis of collision tumors existing of MM and BCC remains unclear [2]. To our knowledge it has not been yet established whether there is a concordant genetic background or independent origin as a possible cause for the development of such a compound tumor. We, therefore, present the extremely rare case of a collision tumor of MM and BCC and the results of a genome-wide analysis by single nucleotide polymorphism array (SNP-Array) for detection of identical genomic aberrations.