Beyond the ordinary: A rare glimpse of PEComa TFE3 rearranged in soft tissue

Abstract

The term “Perivascular epithelioid cells” was described as early as 1992. WHO has defined PEComas as mesenchymal tumors composed of histologically and immunohistochemically distinctive perivascular epithelioid cells. These tumors have a varied morphology including sheets and nested pattern comprising of epithelioid to spindle tumor cells with increased vasculature often in a sinusoidal pattern. PEComas show immunoreactivity for melanocytic and smooth muscle markers, however small number cases show lack of muscle marker expression along with strong TFE3 nuclear positivity. Here we describe a PEComa of soft tissue of leg, TFE3 rearranged.