Iwao Nakayama

FINE STRUCTURAL COMPARISON OF EWINGS SARCOMA WITH NEUROBLASTOMA

Two cases of Ewings sarcoma and two of neuroblastoma, rosette forming and round cell type, were studied electron microscopically and their fine structures were compared. The neoplastic cells of Ewings sarcoma were characterized by aggregated glycogen particles in the cytoplasm. They had pseudopod‐like cytoplasmic processes having tight junctions, which never contained microtubules or mitochondria. Ewings sarcoma cells exhibited several stages of cell maturation and some mature cells possessed a large amount of smooth and rough endoplasmic reticulum, large Golgi complexes and numerous phagosomes containing glycogen particles as well as cytoplasmic organelles. The neoplastic cells of neuroblastoma, rosette forming type, were characterized by synaptic junctions and numerous cytoplasmic processes with production of neurites containing microtubules, neurofibrils, mitochondria and a few catecholamine granules. A few cytoplasmic processes containing mitochondria were observed even in the round cell type.

SARCOMA BOTRYOIDES ARISING FROM THE BILIARY TRACT OF CHILDREN — A CASE REPORT WITH REVIEW OF THE LITERATURE

Sarcoma botryoides (embryonal rhabdomyosarcoma) originating from the common bile duct is reported in a 4‐year‐old girl. Grossly, the tumor is characterized by multiple polypoid and grape‐like projections into the lumen of the common bile duct and shows plate‐like thickening of the common bile duct wall. On multiple cut‐sections these polypoid masses are soft and light yellow white except for multifocal hemorrhage. Histologically the tumor consists of undifferentiated mesenchymal cells with a myxomatous appearance; rhabdomyoblasts with varing degree of maturation are scattered here and there within the matrix. These cells are characterized by a strap and racket shape with abundant eosinophilic cytoplasm and elongated cytoplasm with cross striations. The histogenesis of the tumor may be related possibly to an abnormal differentiation of the primitive mesenchymal cells toward striated muscle cells.

Histological and fine structural studies on pigmented neuroectodermal tumor of infancy.

Pigmented neuroectodermal tumor of infancy originating from the anterior maxilla in a two‐month‐old male has been studied by light and electron microscopy. The tumor is characterized histologically by two types of neoplastic cells embedded in considerable amounts of fibrous stromal tissue. The first type of cell is cuboidal to columnar in shape with an epithelial appearance having abundant cytoplasm; either scanty or a heavy accumulation of melanin pigment is observed in the cytoplasm. These cells are aligned along the cleft‐like space or arranged in small ductal structures. Electron microscopy shows the characteristic features of melanocytic cells having a varying degree of asynchronous maturation of melanosomes. The second type of cells is small and round in shape and has a hyperchromatic nucleus and scanty cytoplasm, resembling neuroblastic cells or lymphocytes. Electron microscopy reveals cytoplasmic processes resembling immature neurits which protrude into the intracellular space; a small number of secretory granules having a central core surrounded by a single limiting membrane are observed in the cytoplasm and cytoplasmic processes.

Gastric Teratoma of Children--A Case Report with Review of the Literature

A case of gastric teratoma in a 3‐month‐old male infant is reported. A large mass showing endogastric growth was located on the lesser curvature of cardiac region and measured 6.5times5x4 cm. Histologically the tumor was composed of the elements derived from three germ layers including squamous, cuboidal and high columnar epithelium with or without cilia, fat tissue, smooth muscle, cartilage and neural tissue. Large parts of these elements appeared to be predominantly mature but some of the neural tissue showed primitive immature structures. Forty‐four reported cases of gastric teratoma were briefly reviewed. ACTA PATH. JAP. 27: 749˜758, 1977.

An ultrastructural study of synthesis and release of beta granules in the human pancreas

The mechanism of synthesis and release of beta granules has been studied by electron microscopy in normal, hyperfunctioning and hypofunctioning human pancreatic tissue. The core of beta granules shows a great variation in structure and electron density supporting the concept that beta granules exhibit different secretory cycles. Granules were tentatively divided into three groups on the basis of differences in electron density of the granule core. Type one granule is considered to be a storage granule, whereas type two granule is thought to participate in the active release of insulin by intracytoplasmic dissolution. Type three granule is thought to be intermediate in structure between the first two types. It is concluded that granular insulin is formed in the Golgi complexes where the progressive development of the granule takes place.

GIANT LYMPH NODE HYPERPLASIA IN EXTRATHORACIC LYMPH NODES‐REPORT OF TWO CASES WITH A REVIEW OF THE LITERATURE

Two cases of giant lymph node hyperplasia occurring in extrathoracic regions are reported, one on the right side of the supra‐and infraclavicular fossa, pectoral muscle and axilla, and the other in the right groin. In both cases enlarged masses were removed several times having arisen from slow growing preexisting smaller masses. The histological features of all masses were identical, although removed at different times during the course of the disease. Both cases were characterized by marked proliferation of lymphoid follicles and capillaries, and infiltration of plasma cells. Fibrous thickening and hyalinization of the capillaries varied somewhat in severity from one case to the other. It is thought that the histogenesis of the lesion is related to chronic inflammation rather than to a hamartoma.

FINE STRUCTURAL STUDIES ON THE FATE OF “CASTRATION” CELLS IN THE RAT ADENOHYPOPHYSIS AFTER BILATERAL OOPHORECTOMY

The fate of castration cells has been studied by electron microscopy after bilateral, oophorectomy. The castration cells were characterized by a large lake‐like dilatation of rough endoplasmic reticulum which occupied almost the entire cytoplasm, and first appeared at 5 weeks after operation. Castration cells showed cellular suppression after 15 weeks of the experiment but no degenerative changes were observed at any experimental period. At the later stage of the experiment numerous secretory granules reaccumulated in the cytoplasm of the gonadotrophs and concomitantly lake‐like dilatation of rough endoplasmic reticulum in some gonadotrophs gradually decreased and finally disappeared from the cytoplasm. Proportion of the castration cells and mean diameter of the largest cisterane of rough endoplasmic reticulum in each cell attained maximum value at 9 weeks after the operation; thereafter both parameters returned toward normal, although they still remained at a higher level than in controls at 18 weeks after the operation.

FINE STRUCTURAL STUDIES OF RAT ADENOHYPOPHYSIS —EFFECTS OF EXOGENOUS GROWTH HORMONE AND HYPOTHALAMIC LESIONS ON SOMATOTROPHS

The response of rat pituitary somatotrophs to transplantation of the MtT‐W10 pituitary tumor and prolonged treatment with large doses of purified bovine growth hormone was examined. The effects of hypo‐thalamic lesions on the somatotrophs were also studied.