PGR and neoplasm: Immunohistochemical staining showed that the tumor cells were diffusely positive for hematopoietic progenitor cell antigen (CD34), B-cell lymphoma (Bcl-2), cluster of differentiation 99, but negative forepithelial membrane antigen (EMA), progesterone receptor (PR), and glial fibrillary acidic protein (GFAP), moderate staining for smooth muscle actin (SMA) with the proliferation labeling index of Ki67 antibody <2% (Fig. 5).