Primary leiomyosarcomas arising in the adrenal gland are exceedingly rare, with only 3 cases reported in the literature. We present the clinical, morphologic, and immunohistochemical features of a pleomorphic leiomyosarcoma, a variant of leiomyosarcoma that has not been described in the adrenal gland. A 63-year-old man presented with a 1-year history of enlarging right upper quadrant mass and pulmonary nodule. A diagnosis of metastatic pulmonary carcinoma to the adrenal gland was rendered on a needle biopsy specimen. Preoperative chemotherapy reduced only the pulmonary mass but not the adrenal mass, which continued to enlarge. Documented by computed tomography and confirmed at surgery, the tumor had completely replaced the right adrenal gland, invading into both the posterior aspect of the right liver and the superior pole of the right kidney. Histologic sections showed a diffuse proliferation of pleomorphic, large, and polygonal neoplastic cells with prominent nucleoli. Many bizarre mitotic figures were present. The neoplastic cells were strongly positive for desmin, calponin, and vimentin. Approximately 80% of the neoplastic cells were positive for the proliferation marker Ki-67. They were negative for smooth muscle actin, muscle-specific actin, myoglobin, myogenin, CD117, cytokeratins, carcinoembryonic antigen, epithelial membrane antigen, chromogranin, CD34, CD31, S100 protein, and HMB-45.