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. Author manuscript; available in PMC: 2016 Aug 15.
Published in final edited form as: J Clin Pathol. 2015 Mar 6;68(6):418–426. doi: 10.1136/jclinpath-2015-202945

TABLE 3.

Folpe criteria for prognosis in PEComa (from Folpe et al53)

Criteria Percentage Fulfilling Criteria With Aggressive Behavior Comment
Benign No worrisome features (<5 cm, non-infiltrative, non-high nuclear grade and cellularity, mitotic rate ≤1/50HPF, no necrosis, no vascular invasion) 0 of 22 (0%)
Uncertain malignant potential Nuclear pleomorphism/multinucleated giant cells only or 0 of 6 (0%) “Symplastic” PEComa probably benign, but few reported cases
Size >5 cm only 2 of 17 (12%) Large tumors should be extensively sampled to exclude areas with other worrisome features
Malignant Two or more worrisome features (>5 cm, infiltrative, high nuclear grade and cellularity, mitotic rate ≥1/50HPF, necrosis, vascular invasion) 12 of 17 (71%)