Correct: C

Histology: This is an adrenal neoplasia that measured 12 cm in size and is composed of cords and sheets of epithelial cells with eosinophilic cytoplasm. There is mild nuclear pleomorphisms and mitoses are not frequent. Necrosis or vein invasion are not seen.

Discussion: Adrenocortical neoplasms are sometimes difficult to classify into benign or malignant and the Weiss criteria has been establish to predict malignant behavior.

Original Weiss criteria for malignancy, modified as indicated below, requires 3+ of these factors:
– Nuclear grade III or IV based on Fuhrman criteria
– > 5 mitotic figures/50 HPF (40x objective), counting 10 random fields in area of greatest number of mitotic figures on 5 slides with greatest number of mitoses
– Presence of atypical mitotic figures (abnormal distribution of chromosomes or excessive number of mitotic spindles)
– Clear or vacuolated cells comprising 25% or less of tumor
– 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)
– 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
– Each criterion is scored 0 when absent and 1 when present in the tumor

Modified Weiss criteria:
– Mitotic rate > 5 per 50 high power fields
– Cytoplasm (clear cells comprising 25% or less of the tumor)
– Abnormal mitoses
– Necrosis
– Capsular invasion
– Calculate: 2x mitotic rate criterion + 2x clear cytoplasm criterion + abnormal mitoses + necrosis + capsular invasion (score of 3 or more suggests malignancy)

This criteria does not apply to neoplasms in children and oncocytic (eosinophilic) tumors. Because eosinophilia of more than 70% is a criterium in both original and modified, an oncocytic tumor will score points even when completely benign. In those situations, Ki67 can be helpful and more than 5% correlates with malignant behavior, although by itself, Ki67 is not used to render a diagnosis of malignancy. Below is the diagnostic criteria for oncocytic adrenocortical neoplasms.
Lin–Weiss–Bisceglia (LWB) system for diagnostic categorization of oncocytic adrenocortical neoplasms:
Major criteria:
– Mitotic count >5 per 50 high-power fields
– Atypical mitoses
– Venous invasion
Minor criteria:
– Size >10 cm and/or weight >200 g
– Necrosis
– Sinusoidal invasion
– Capsular invasion
The presence of one major criterion indicates malignancy, one to four minor criteria present indicates uncertain malignant potential, and the absence of all major and minor criteria is indicative of benign biological behavior
References:
– Am J Surg Pathol 2002; 26:1612
– Am J Surg Pathol 1984; 8:163