A case of uterine adenomyoma with bizarre smooth muscle cells mimicking leiomyosarcoma

We report a case of adenomyoma of the uterus that was cytologically difficult to distinguish from leiomyosarcoma. Examination of a uterine cervical smear revealed numerous spindle cells that were present in cell clusters or as isolated cells. These cells contained nuclei that were oval‐shaped/elongated with nucleoli and delicate wispy cytoplasm. Large and bizarre nuclei were also identified. Based on these cytological findings leiomyosarcoma was considered: however, this diagnosis remained uncertain because of the absence of mitosis and/or necrotic substance. Histologically, we recognized leiomyomatous smooth muscle cells growing in a solid pattern and intermingled with endometrial‐type glands. Moreover, bizarre smooth muscle cells were observed in the surface layer of the tumor. These observations suggest that for a diagnosis of uterine leiomyosarcoma the presence of mitosis and/or necrosis is important in addition to nuclear atypia. Diagn. Cytopathol. 2005;32:288–291. © 2005 Wiley‐Liss, Inc.