Slowly growing, ulcerating nodule on the posterior ankle 

A 34-year-old Haitian man presented with a 1-year history of a gradually en- larging, ulcerating nodule on the right posterior ankle that bled after trauma. The patient denied any history of prior trauma at the site of the lesion and foreign travel.There were no HIV risk factors or personal or family history of skin cancer.The patient was otherwise healthy with no additional complaints. Physical examination revealed a 1.4 cm firm, hyperpigmented nodule with a yellow crateriform center on the right posterior ankle (Figure 1).A punch biopsy was performed (Figures 2, 3). Histopathologic examination revealed a superficial and mid-dermal, multi- nodular proliferation of bland epithelioid cells with occasional foci of ductal differentiation embedded in a fibrotic stroma. Focal epidermal connection and mucinous metaplasia were noted. Immunohistochemical stains revealed diffuse positive staining of the lesional cells with cytokeratins (high and low) and variable positivity with epithelial membrane antigen (EMA), as well as negative S100P. Fungal, viral, and mycobacterial tissue cultures were negative and RPR was non-reactive. Bacterial tissue culture was positive for Prevotella oris and Staphylococcus aureus.