Histologic variants of Merkel cell skin cancer

High-power photomicrographs of hematoxylin and eosin-stained sections of a skin biopsy showing three different histologic variants of skin Merkel cell cancer (MCC). Top panel: intermediate variant of MCC with vesicular, basophilic nuclei containing prominent nucleoli and multiple mitoses. Middle panel: small-cell variant, histologically indistinguishable from bronchial small-cell carcinoma. Lower panel: trabecular variant, which is rare and normally only seen as a small component of a mixed type of MCC.