Kazunari Okada

An Electron Microscopic Study of Hepatic Angiomyolipoma

Three cases of hepatic angiomyolipoma, each composed of an intimate mixture of numerous abnormal blood vessels and various‐sized fat, spindle and/or epithelioid cells, are presented along with the findings of an electron microscopic study. The spindle cells were confirmed to be smooth muscle by immunohistochemical staining for des‐min and by their ultrastructural characteristics. The mature fat cells, smooth muscle cells, immature short spindle cells apparently intermediate or transitional between the former two cell types, and the epithelioid cells were observed adjacent to the endothelial cells. Ultra‐structurally, the epithelioid cells were characterized by unusual cytoplasmic organelles such as myofilaments having focal densities and dense attachments, numerous large electron‐dense bodies, and a large number of glycogen particles and lipid droplets. Therefore, it is considered that the immature short spindle and epithelioid cells in hepatic angiomyolipoma might be primitive mesenchymal cells having an ability to differentiate toward both smooth muscle and fat cells. Acta Pathol Jpn 39 : 743‐749, 1989.

Giant hepatic angiomyolipoma simulating focal nodular hyperplasia

A case of hepatic angiomyolipoma occurring in a 41-year-old woman, the eighteenth case in literature, is reported herein. The radiographic imagings of the tumor simulated those of focal nodular hyperplasia; namely, the tumor was hyperechoic on ultrasound, hypodense on computed tomography, hypervascular on angiography, and exhibited an uptake of technetium (Tc)-99m phytate. The diagnosis was established after successful removal of the huge tumor from the right hepatic lobe. Histologically, the tumor was angiomyolipoma which was made up of three components, blood vessels, smooth muscle and fatty tissue. Furthermore, extramedullary hematopoiesis, which is usually seen in this tumor was confirmed. The differentiation of hepatic angiomyolipoma from FNH is also discussed.

Fibrolamellar hepatocellular carcinoma coexistent with a hepatocellular carcinoma of common type: report of a case.

A case of small fibrolamellar hepatocellular carcinoma (HCC) coexistent with a HCC of common type is herein reported. A 56-year-old man was diagnosed as having multi-nodular type HCC with liver cirrhosis. The serum alpha-fetoprotein (AFP) level was slightly increased. The patient underwent a partial caudate lobectomy and lateral segmentectomy. Histologically, both resected tumors were small HCCs measuring less than 2 cm in diameter. One was a fibrolamellar type located in the caudate lobe, while the other was the common type in the lateral segment of the liver. Positive immunohistochemical staining for AFP was observed in the tumor cells of the HCC of common type but was not observed in the fibrolamellar HCC. We also reviewed previously reported cases of fibrolamellar HCC in Japan, and discussed the clinicopathologic implications of this disease.

An immuno-electron microscopic study on intra and extracellular localization of alpha-fetoprotein in human hepatocellular carcinoma.

Intra and extracellular localization of alpha‐fetoprotein (AFP) has been studied by an indirect peroxidase labeled antibody method using 12 cases of human hepatocellular carcinoma (HCC). With light microscopic observation, positive immuno‐staining for AFP was observed in 6 out of 12 cases and demonstrated as granular or diffuse deposits in the cytoplasm of neoplastic hepatocytes. In electron microscopic studies, 8 cases showed the positive immuno‐staining for AFP in the neoplastic hepatocytes. Intracellular antigen was well circumscribed within certain cell organelles with the positive immuno‐staining for AFP being observed in perinuclear space, cisternae of rough endoplasmic reticulum (RER), Golgi complexes, and secretory vesicles. In addition, the positive immuno‐staining for AFP was observed in bile canaliculus‐like space in most cases with increased levels of serum AFP and in some cases which showed normal levels of serum AFP. Furthermore, the positive immuno‐staining for AFP was also observed in intercellular, Disses‐like and sinusoid‐like spaces, and micropinocytotic and lysosome‐like vesicles in the endothelial cells in a few cases which showed excessively high value of serum AFP. ACTA PATHOL. JPN. 37:915–928, 1987.