Special staining for smooth muscle cells, such as actin, desmin, or myosin, and for vascular endothelium, such as factor VIII or CD31 can aid in differentiating angioleiomyoma from haemangioma, angiofibroma, fibroma, angiomyolipoma, and angiomyosarcoma [9]. The gene discussed is PECAM1; the disease is angioleiomyoma.