Table 2.

Original and modified Weiss criteria for evaluating malignancy in adrenal cortical neoplasms

Original Weiss criteria	Modified Weiss criteria
Nuclear grade III or IV based on Fuhrman criteria	Mitotic rate >5 per 50 high-power fields
>5 mitotic figures/50 HPF (40× objective), counting 10 random fields in area of greatest number of mitotic figures on 5 slides with greatest number of mitoses	Cytoplasm (clear cells comprising 25 % or less of the tumor)
Presence of atypical mitotic figures (abnormal distribution of chromosomes or excessive number of mitotic spindles)	Abnormal mitoses
Clear or vacuolated cells comprising 25 % or less of tumor	Necrosis
Diffuse architecture (more than 1/3 of tumor forms patternless sheets of cells; trabecular, cord, columnar, alveolar or nesting pattern is not considered to be diffuse)	Capsular invasion
Microscopic necrosis
Venous invasion (veins must have smooth muscle in wall; tumor cell clusters or sheets forming polypoid projections into vessel lumen or polypoid tumor thrombi covered by endothelial layer)
Sinusoidal invasion (sinusoid is endothelial lined vessel in adrenal gland with little supportive tissue; consider only sinusoids within tumor)
Capsular invasion (nests or cords of tumor extending into or through capsule with a stromal reaction); either incomplete or complete
Calculate: score of 3 or more suggests malignancy	Calculate: 2× mitotic rate criterion + 2× clear cytoplasm criterion + abnormal mitoses + necrosis + capsular invasion (score of 3 or more suggests malignancy)
Each criterion is scored 0 when absent and 1 when present in the tumor	Each criterion is scored 0 when absent and 1 when present in the tumor