Table 1.

Worrisome features predictive of outcome in patients with PEComas.

Folpe et al. (12)		Schoolmeester et al.(19)		Bennett et al (16)
category	Histologic criteria	Category	Histologic criteria	Category	Histologic criteria
Benign	No worrisome features: less than5 cm in diameter Non-high nuclear grade and cellularity Mitotic rate ≤ 1/50 HPF No necrosis No vascular invasion	Benign/uncertain malignant potential	Less than 4 worrisome features: size ≥ 5 cm high-grade atypia (excluding degenerative atypia) mitoses > 1/50 HPF, necrosis lymphovascular invasion	Uncertain malignant potential	Less than 3 worrisome features: size ≥ 5 cm high-grade atypia (excluding degenerative atypia) mitoses > 1/50 HPF, necrosis lymphovascular invasion
Uncertain malignant potential	One or both of the following features: Nuclear pleomorphism/multinucleated giant cells only or size>5 cm	Malignant	4 or more worrisome features: size ≥ 5 cm, high-grade atypia (excluding degenerative atypia) mitoses > 1/50 HPF, necrosis lymphovascular invasion	Malignant	3 or more worrisome features: size ≥ 5 cm, high-grade atypia (excluding degenerative atypia) mitoses > 1/50 HPF, necrosis lymphovascular invasion
Malignant	Two or more worrisome features: >5 cm in diameter Infiltrative High nuclear grade and cellularity Mitotic rate > 1/50 HPF Necrosis Vascular invasion

Legend: HPF: high power field