Rodent Liver Lesions - Neoplastic

R. R. Maronpot

maronpot@me.com

Photomicrographs courtesy of the National Toxicology Program (http://ntp.niehs.nih.gov)

Hepatocellular adenoma

• Nodular and compressing

• Oblique impingement on surrounding parenchyma

• Loss of lobular structure

• Difference in cell size and/or tinctorial staining

• Occasional trapped portal triads

Hepatocellular tumor

Hepatocellular Adenoma

Hepatocellular Adenoma

Hepatocellular Adenoma

Hepatocellular carcinoma

• Locally infiltrative

• Cellular pleomorphism

• Loss of normal lobular structure

• Increased mitosis, necrosis, and/or hemorrhage may be present

• Altered tinctorial staining

• Variable growth patterns

– Trabecular, acinar, solid, other

Hepatocellular tumor

Hepatocellular Carcinoma

Hepatocellular Carcinoma

Hepatocellular Carcinoma

Hepatocellular Carcinoma

Hepatocellular Carcinoma

Hepatocellular Carcinoma

Hepatocellular carcinoma

Carcinoma arising in Adenoma

Carcinoma Arising in Adenoma

Hepatoblastoma

• Discrete nodular growth with variable structure, often within hepatocellular adenoma or carcinoma

• Cells often small, strongly basophilic, and may be elongated

• Cells arranged radially, concentrically, as rosettes, trabeculae and/or pseudoglands

• Vascular cavities

• Osteoid differentiation may be present

Hepatoblastoma arising in adenoma

Hepatoblastoma with Osseous Metaplasia

Cholangioma

• Variable size and shape glandular acini

• Expansive and compressive growth

• Cells mostly in a single layer without surrounding stroma

• Cells reasonably well differentiated with slightly basophilic cytoplasm

• Simple and cytic forms

• Occasional trapped hepatocytes

Cholangioma

Cholangioma

Cystic Cholangioma – Benign Bile Duct Tumor

Glandular structures linedby a single layer of cuboidalto columnar epithelium

Cystic Cholangioma

Cholangiocarcinoma

• Locally invasive glandular, solid and/or papillary growth pattern

• Cells are single or multiloayers with large nuclei and basophilic cytoplasm

• May be associated with some fibrosis

• A controversial version with intestinal metaplasia, extensive fibrosis, dilated mucus-and debris-filled glands, and inflammation is currently being debated

Cholangiocarcinoma

Cholangiocarcinoma

Well Differentiated Cholangiocarcinoma

Well-Differentiate Cholangiocarcinoma

Hepatocholangiocellular adenoma

• Combines merged features of hepatocellular cords and single layered biliary ductules

• Hepatocytes may form ductules that resemble biliary cells

Hepatocholangioma

Hepatocholangioma

Hepatocholangioma

Hepatocholangiocellular carcinoma

• Features of hepatocellular carcinoma and/or cholangiocarcinoma

• Cellular stratification and atypia of biliary component

• Increased mitoses may be present

Hepatocholangiocarcinoma

Hepatocholangiocarcinoma

Hepatocholangiocarcinoma

Hepatocholangiocarcinoma

Hepatocholangiocellular carcinoma

Hepatocholangiocellular Carcinoma

Hepatocholangiocellular Carcinoma

Hepatocholangiocellular Carcinoma

Hepatocholangiocellular Carcinoma

Hepatocholangiocellular Carcinoma

Hepatocholangiocellular Carcinoma

Ito cell tumor

• Focal to diffuse single or multicentric sheets and/or clusters of variably sized and shaped cells

• Tumor cells often vacuolated and present along hepatocyte cords

• Unencapsulated growth that replaces normal hepatic parenchyma

• Spindle-shaped cells may be part of growth

Ito Cell Hyperplasia Ito Cell Tumor

Ito Cell Hyperplasia

Ito Cell Tumor

Ito Cell Tumor

Ito Cell Tumor

Ito Cell Tumor

Ito Cell “Tumor”

Ito Cell Tumor in a Rat

Ito Cell Tumor in a Rat

Histiocytic sarcoma

• Single or multicentric nodules composed of uniform population of round to oval cells with foamy cytoplasm

• Growth along sinusoids and vascular structures

• Multinucleated giant cells may be present

• Mitoses may be numerous

Histiocytic Sarcoma

Histiocytic Sarcoma

Histiocytic Sarcoma

Histiocytic Sarcoma

Histiocytic Sarcoma

Histiocytic Sarcoma

Histiocytic Sarcoma

Hemangioma

• Blood-filled spaces lined by a single layer of uniform endothelial cells without atypia

• Occasional solid areas of uniform endothelial cells without atypia may be present

• May be multifocal and associated with angiectasis

• Capillary and cavernous growth patterns are seen

Hemangioma

Hemangioma

Hemangioma

Hemangioma

Hemangiosarcoma

• Pleomorphic multilayered and/or clustered pleomorphic endothelial cells

• Various poorly formed and infiltrative vascular growth patterns

• Undifferentiated areas and mitotic figures often present

Hemangiosarcoma

Hemangiosarcoma

Hemangiosarcoma

Hemangiosarcoma

Hemangiosarcoma

Lymphoma in a Tg Mouse

Lymphoma in a Tg.AC Mouse

Erythroleukemia in a Control Tg.AC Mouse

Erythroleukemia in a Control Tg.ACMouse

Erythroleukemia in a TgAC Mouse

Erythroleukemia in a TgAC Mouse

Mononuclear Cell Leukemia

Mononuclear Cell Leukemia