A Case of Superficial Leiomyosarcoma, and a Review of Japanese Cases

We report a case of leiomyosarcoma in a 55-year-old Japanese female. She developed an erythematous nodule, 1.5 cm in diameter, on her right thigh. The totally excised specimen contained tumor cells with variously sized, chromatin-rich nuclei. Gitter staining revealed the so-called encased picture, immunohistopathological staining was positive for smooth muscle actin, and electron microscopy revealed filaments with focal densities. A diagnosis of leiomyosarcoma was made based on these findings, which suggested a muscle cell origin. Normal arrector pili muscles were continuous from the tumor, further suggesting the tumor's origin. The presence of Epstein-Barr virus-encoded RNA (EBER) was examined by in situ hybridization with negative results.