“Malignant” Perivascular Epithelioid Cell Neoplasm: Risk Stratification and Treatment Strategies

Table 1

Proposed classification of PEComas (adapted from Folpe et al. [7]).

High risk features	Risk category
(1) Size >5 cm; (2) Infiltrative growth pattern; (3) High nuclear grade and cellularity; (4) Mitotic Rate >1/50 HPF; (5) Necrosis; (6) Vascular invasion	“Benign”; <2 high risk features and size < 5 cm
	“Uncertain malignant potential”; Size ≥5 cm with no other high risk features OR nuclear pleomorphism/multinucleated giant cells only
	“Malignant”; 2 or more high risk features