Clonal heterogeneity in a case of Merkel cell carcinoma demonstrated by flow cytometry

A 66-year-old female patient is presented in whom a rapidly growing tumour developed on the glabella. Light and electron microscopy confirmed Merkel cell carcinoma. Flow cytometry (FCM), performed of a tumour specimen, yielded multiple aneuploid stem lines. The FCM data are discussed with regard to the histological features and the biological behaviour of the tumour.