Malignant perivascular epithelioid cell tumor (PEComa) of the femur: a case report and literature review

BACKGROUND We describe a case of malignant perivascular epithelial cell tumor (PEComa) arising primarily in the distal left femur of a 47-year-old male. CASE PRESENTATION The patient presented with pain accompanied by progressive swelling of his left thigh. Computed tomography (CT) scan and magnetic resonance imaging (MRI) revealed an osteolytic lesion. Curettage of the lesion was reported as a clear cell tumor with recommendation for exclusion of a metastatic clear cell carcinoma. However, thorough examinations did not find any primary site elsewhere, apart from the presence of bilateral pulmonary metastases. Evaluation of the submitted H & E slides identified a malignant PEComa which was further confirmed by subsequent immunohistochemical study. CONCLUSIONS The occurrence of PEComa as a primary bone lesion is extremely rare. We present here a malignant PEComa of the distal left femur, and summarize the clinicopathological characteristics of this rare entity with literature review. VIRTUAL SLIDES The virtual slide (s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/5729035221600545 .