Specialized intercellular junctions in human intracranial germinomas

Pineal germinomas and testicular seminoma: a comparative ultrastructural study with special references to early carcinomatous transformation

We have investigated the ultrastructural characteristics of 16 cases of pineal germinomas and compared them with those of 18 cases of testicular seminomas. Glandular differentiation of tumor cells was found in both though it was more consistently noted in pineal germinomas than in testicular seminomas. This feature was interpreted to represent early carcinomatous transformation of germinoma cells. It not only explains the difficulties occasionally encountered in distinguishing germinoma and its anaplastic variant from embryonal carcinoma, but also has implications for our understanding of germ cell neoplasia, particularly the place of germinoma/seminoma in the nosology of such tumors.

Exocytosis of neurosecretory granules in small cell undifferentiated carcinoma

The tumor cells in the pleural effusions of a case of small cell undifferentiated carcinoma have been studied by light microscopy and by thin section and freeze-fracture electron microscopy. Evidence of exocytosis of neurosecretory granules from the tumor cells is presented. The tumor cells form clumps, with the cells joined by focal tight junctions and small desmosomes. These findings are discussed with reference to the neuroendocrine origin of these tumors and the role of the junctional complexes in the formation of tumor cell aggregates.

Ultrastructural study of intracranial yolk sac tumor: with special reference to the oncologic phylogeny of germ cell tumors

Ultrastructural studies of yolk sac tumors (YST) have generally demonstrated the resemblance of this neoplasm to the primitive human yolk sac. However, these studies have failed to explain the common occurrence of mixed germ cell tumors with yolk sac elements. This report describes the ultrastructural features of a suprasellar YST. This tumor resembled those previously described. Also demonstrated, however, was the presence of primitive germ cells admixed within the neoplasm. A new schema is proposed based on these observations for the interrelationship of germ cell tumors, which may explain the common occurrence of mixed germ cell tumors.

Germinomas of the brain. Light and electron microscopic study. A report of seven cases

The authors report seven cases of intracerebral germinomas studied on autopsy and/or biopsy material. Electron microscopy was done in five cases. Tumors were located on the middle line of the brain (pineal area, suprasellar region, third ventricle). Light microscopic features were stereotyped with PAS + round tumor cells and inflammatory mononuclear cells. By electron microscopy, fenestrated nucleoli, glycogen storage and annulate lamellae were always found, as well as a striking macrophagic activity of histiocytes. This immune reaction is supposed to contribute to the relatively favorable prognosis of these original brain tumors.

Pathological survey of intracranial germinoma and pinealoma in Japan

Pathologic survey was performed on 43 cases of intracranial germinoma and 12 cases of pinealoma. The present study suggests that, in Japan, the incidence of teratoma groups including germinoma is remarkably higher than that in U.S. and Europe, whereas the rate of true pinealoma is lower. Using ultrastructural, enzyme-histochemical, and fluorescence-histochemical methods for a few surgical specimens, a strong similarity between intracranial germinoma (so-called "pinealoma" with a two-cell pattern) and seminoma and dysgerminoma was confirmed. The true pinealoma could be classified as pineoblastoma and pineocytoma, according to the degree of pineocyte differentiation of the tumor cells, and as "neuroblastoma-like" and "pineal-like" on the basis of the histologic architecture.

Macrophagic activity in intracerebral germinoma: ultrastructural study of a case

This report presents the ultrastructural study of a germinoma of the third ventricle occurring in a 13 year old boy. The electron microscopic data showed similarities linking this tumor to gonadal and mediastinal germinomas and emphasized the exceptional glycogenic storage in tumor and stroma cells. Another morphological analogy was the intense macrophagic activity that led to tumor cell phagocytosis. The authors discuss the meaning of such an immune response, which is usually not observed in cerebral tumors.

Anaplastic seminoma of the testis: ultrastructural analysis of three cases

Three anaplastic seminomas of the testis were examined by transmission electron microscopy, and the ultrastructural features are described for comparison with those reported in other seminomas and related neoplasms. It is concluded that anaplastic seminomas are similar ultrastructurally to classic testicular seminomas, extragondal seminomas, and ovarian dysgerminomas, all of which are less differentiated than spermatocytic seminomas.

Ultrastructural study of the pineal germinoma in vivo and in vitro

The fine structure of a pineal germinoma was studied in tissue blocks and in tissue culture. The original tumor contained large primary tumor cells, lymphocytes, macrophages, plasma cells, and astrocytes. The large primary tumor cells were characterized by large nuclei, relatively scanty organelles, abundant glycogen, and junctional complexes. The neoplasm grew well in vitro and, with the exception of plasma cells, contained the same cell types found in vivo. The ultrastructural characteristics of the cells in vivo and in vitro were similar. In culture there were few large primary tumor cells. Macrophages, often involved in active phagocytosis, were prominent in the original tumor and were the most common cell type found in vitro. A tumor-associated immune response is postulated in this neoplasm.

Some new observations in an intracranial germinoma

A case of an intracranial germinoma from the suprasellar region of a 9-year-old girl was examined in the electron microscope. The tumor consists, for the most part, of both large polygonal and small lymphocyte-like elements. Annulate lamellae are common in the epithelial cells. The small blood vessels are fenestrated, and the endothelial cells contain tubular bodies, membrane-bounded vacuoles containing dense fluid and occasional tubules, arrays of tubules within the nuclear envelope and rough endoplasmic reticulum, and a markedly irregular luminal surface. Dense, lamellated structures are present in the widened, collagen-containing perivascular spaces.