. Author manuscript; available in PMC: 2014 Oct 13.

Published in final edited form as: Toxicol Pathol. 2012 Dec 21;41(2):151–180. doi: 10.1177/0192623312467102

TABLE 2.

Comparison of atypical focus of cellular alteration, focus of cellular alteration, adenoma, and carcinoma.

Focus of cellular alteration, atypical

Eosinophilic or mixed cell (microvesicular) foci

Vary in size, round to oval, sometimes irregular

Hepatic plates merge imperceptibly with surrounding hepatocytes

Occasional compression

Occasional irregular borders

Cytomegaly, karyomegaly, anisocytosis, anisokaryosis

Nuclear invaginations, cytoplasmic inclusions, multiple prominent nucleoli

Focus of cellular alteration (basophilic, eosinophilic, clear, or mixed cell foci)

Vary in size, range from less than one hepatic lobule to up to several lobules in diameter

Round to oval, sometimes irregular

Hepatic plates merge imperceptibly with surrounding hepatocytes

Little or no compression

Eosinophilic foci: enlarged cells with granular pale pink cytoplasm

Clear cell foci: variable amount of cytoplasmic vacuoles (glycogen)^a

Basophilic foci: increased cytoplasmic basophilia, cells often smaller than normal^a

No cellular atypia^a

Adenoma

Well-circumscribed nodules^a

Distinct compression of adjacent parenchyma^a

Hepatic plates at margins impinge at sharp angles to the surrounding normal liver plates^a

Well-differentiated hepatocytes that are variable in size and tinctorial properties (eosinophilic, basophilic, clear, or admixed)

Area greater than one liver lobule

Solid or irregular plates 1–3 cells layers thick

Absence of normal lobular architecture with trapped central veins and portal tracts

May have some cellular atypia, eosinophilic cytoplasmic inclusions, mitotic figures

Carcinoma

Masses vary in size and color (eosinophilic, basophilic, vacuolated, or admixed)

Cellular atypia and mitotic figures are common

May see eosinophilic cytoplasmic inclusions

Nuclei variable in size, usually enlarged and hyperchromatic

Nucleoli distinct, larger, centrally located

Border often irregular (distinct invasion and compression)^a

May have necrosis and hemorrhage^a

Abnormal growth pattern: trabecular, glandular, and/or solid^a

Trabecular pattern 3 or more cell layers thick^a

May see pulmonary metastases^a

Features that are distinctly different from atypical foci.