The value of genotypic analysis in the assessment of cutaneous plasmacytomas

We report a 79-year-old woman with primary cutaneous plasmacytoma in whom polymerase chain reaction (PCR) was used to demonstrate the monoclonality of the tumour. Four years after presentation, further skin lesions occurred and PCR again showed evidence of monoclonality despite the histology being non-specific. The reported frequency of multiple primary cutaneous plasmacytoma is increasing, and the mortality rate of patients with multiple lesions is three times that of those with a solitary lesion. PCR may be a useful technique for assessing such patients at presentation.