An adult male, 268.0 cm, 262.2 kg, code 2 Tursiops truncatus (Field ID GNL010) stranded dead off the coast of Pea Island, NC (35.6 N, 75.5 W). Gross lesions were identified in the musculoskeletal, urogenital, cardiovascular, and digestive systems. In the pylorus, there was a 3.0 X 2.0 cm, raised, white, firm, intramural mass with associated mucosal ulceration. Histologically, the mass was composed of neoplastic spindyloid cells forming irregular bundles and fascicles. Based upon histologic features and immunohistochemical markers for muscle (smooth muscle actin, muscle specific actin), c-kit, and S-100, the mass was consistent with a gastric leiomyoma.