Hepatoblastoma in a Dog.

Abstract

ABSTRACT. A hepatoblastoma was found in a 13-year-old female Maltese dog. Histologically, the tumor showed a wide trabecular pattern and was frequently accompanied with vascular lake formation. Tumor cells were positive for cytokeratin and neuron specific enolase, but negative for chromogranin. Electronmicroscopically, tumor cells were accompanied with continuous basement membrane and had poorly developed desmosomes. Sinusoidal endothelia had fenestration and were surrounded by myofibroblast-like cells. To the best of our knowledge, this paper is the first report of morphological studies on canine hepatoblastoma. -KEY WORDS: canine, hepatoblastoma.J. Vet. Med. Sci. 59(12): 1167-1170, 1997 periodic acid-Schiff (PAS) reaction with or without diastase digestion, Orcein stain, and Watanabe's silver impregnation.Mitoses of tumor cells were counted and the data were compared with those of a canine hepatocellular carcinoma with distant metastasis.Immunohistochemical examination was performed using labelled streptavidin-biotin method with a Histofine kit (Nichirei Corp., Tokyo, Japan). Primary antibodies used were as follows: anti-human cytokeratin antibody (Boehringer Mannheim Biochemica, Mannheim, Germany), anti-human neuron specific enolase (NSE) antibody (Dakopatts, Glostrup, Denmark), anti-bovine chromogranin antibody (Incstar Corp., Stillwater, MN, U.S.A.), anti-α-smooth muscle actin (α-SMA) antibody (Sigma Chemical Co., St. Louis, MO, U.S.A.), and anti-human factor VIIIrelated antigen (FVIII-RAg) antibody (Dakopatts, Glostrup, Denmark). Immunoreaction with primary antibodies was performed for 1 hr at 37°C. Thereafter, biotinylated antirabbit or mouse IgG antibody and peroxidase-labelled streptavidin were sequentially applied to the sections for 15 min each at room temperature. The reaction was visualized with 3,3'-diaminobenzidine in 0.1M Tris HCl buffer (pH 7.6) plus hydrogen peroxide. Sections were counterstained with Mayer's hematoxylin.For electron microscopy, small blocks (1 mm 3 ) of the tumor were fixed in 2.5% glutaraldehyde/0.1 M phosphate buffer for 2 hr at 4°C and post-fixed in 1% osmium tetroxide/0.2 M phosphate buffer for 2 hr at 4°C. The blocks were dehydrated in graded ethanol and embedded in Epoxy resin. Ultra-thin sections were cut and double stained with uranyl acetate and lead citrate and examined by a Hitachi H-300 transmission electron microscope at 75 kV.Histologically, the nodules were consisted of compact proliferation of tumor cells in a wide trabecular pattern (Fig. 1). Many vascular lakes were present in the tumor tissues (Fig. 1). Necrosis and degeneration were rare. However, in the central portions of tumor nests, neoplastic cells fell into degeneration (Fig. 2a) and these portions occasionally connected to the vessels in the stroma (Fig. 2b). The tumor cells had a polarity: their nuclei were located at the opposite site of basal side (Fig. 2a). The nuclei of the tumor cells were round with relatively rich chromatin and did not show atypia or pleomorphism. The nucleus/cytoplasm ratio...

Three Equine Cases of Mixed Hepatoblastoma with Teratoid Features

“…1,3,13,15 Hepatoblastomas are categorized as either epithelial or mixed (epithelial/mesenchymal) variants. The recognized epithelial cell types of hepatoblastoma include fetal, embryonal and fetal, macrotrabecular, or anaplastic small cell types.…”

“…3 Immunohistochemistry and other special stains have been utilized to better characterize hepatoblastomas in both humans and animals. 1,3,5,13,15 However, results can be inconsistent. These staining inconsistencies may be caused by variable epithelial, mesenchymal, and teratoid cell populations, variable intracytoplasmic constituents, such as lipid and glycogen, or cellular anaplasia.…”

“…1,3,5,9,13,15 AFP is traditionally the most consistent marker found in hepatoblastomas. 1,3,5,13,15 The staining characteristics reported here were consistent with those previously reported for hepatoblastomas. The primary hepatic tumors (cases #1, #2, and #3) and metastases (case #2) stained variably positive for AFP, CK, vimentin, and demonstrated variable amounts of lipid (cases #2 and #3) and glycogen (cases #1 and #2).…”

Immunohistochemical Characterization of Hepatoblastomas in B6C3F1 Mice Treated with Diethylnitrosamine and Sodium Phenobarbital.

“…It is, however, in line with the previous observations in human for HCCs with sarcomatoid differentiation [16,21] and HBs [17,25,36] which were positive for neuron-specific enolase (NSE) and S-100 protein. Shiga et al [27] reported a HB in a dog to be positive for NSE, but no neuroendocrine granules were observed on electron microscopic examination. S-100 protein is known to be expressed in many neuroectodermal tissues or neoplasms, as well as various other mesenchymal tissues/tumors [2,9,15,35].…”

Hepatic neuroendocrine carcinoma with metastases to the lymph nodes in a sika deer (<i>Cervus nippon yakushimae</i>)

“…This tumor should be distinguished from hepatoblastoma and metastatic neuroendocrine carcinoma of the pancreas, gallbladder and digestive tract. Tumor cells of hepatoblastomas have argyrophilic granules and are positive for cytokeratin, HepPer-1, α-fetoprotein, NSE and synaptophysin but negative for chromogranin A [2,3,16]. In contrast, neuroendocrine tumors are negative for hepatocyte and α-fetoprotein [5].…”