Table 1.

Various microscopic features used to differentiate leiomyomas from leiomyosarcomas.

Tumor	Cytologic nuclear Atypia	Mitosis	Necrosis	References
Leiomyoma	Absent	Scant	Absent	[6]
Atypical leiomyoma	Nuclear pleomorphism present	Absent	Absent
Well-differentiated leiomyosarcoma	Mild	Present but not numerous	Usually absent	[3]
High grade/poorly differentiated leiomyosarcoma	Nuclear pleomorphism, diffuse atypia	High mitotic count	Common	[7]