Ultrastructure of giant-cell lesions. A peripheral giant-cell reparative granuloma

Peripheral giant cell granuloma. An immunohistochemical and ultrastructural study

OBJECTIVE

To study the nature of multinucleated and mononuclear cells from peripheral giant cell granuloma (PGCG).

MATERIALS AND METHODS

Formalin-fixed, paraffin-embedded sections of 40 cases of PGCG were immunohistochemically stained for vimentin, alpha I-antichymotrypsin, CD68, S-100 protein, lysozyme, leucocyte common antigen (LCA), factor VIII-related antigen and muscle cell actin. Six cases of PGCG were also studied by transmission electron microscopy.

RESULTS

Vimentin, alpha I-antichymotrypsin and CD68 were expressed in both the mononuclear and multinucleated giant cells. Dendritic mononuclear cells, positive for S-100 protein, were noted in 67.5% of the lesions, whereas lysozyme and leucocyte common antigen were detected in occasional mononuclear cells. Ultrastructural examination showed mononuclear cells with signs of phagocytosis and sometimes interdigitations with similar cells. Others presented non-specific characteristics and the third type exhibited cytoplasmic processes and occasional Birbeck granules. Some multinucleated giant cells showed oval nuclei, abundant mitochondria and granular endoplasmic reticulum whereas others presented with irregular nuclei and a great number of cytoplasmic vacuoles.

CONCLUSIONS

Immunohistochemical and ultrastructural results suggest that PGCGs of the jaws are composed mainly of cells of the mononuclear phagocyte system and that Langerhans cells are present in two thirds of the lesions.

An electron microscopy study of Kupffer cells in livers of mice having Friend erythroleukemia hepatic metastases

Kupffer cells, which are part of the reticuloendothelial system, play an important role in clearing pathogenic substances, including tumor cells, from the liver. The role of Kupffer cells in tumor development is very important as Kupffer cells can be manipulated to a tumoricidal state with biological response modifiers to kill tumor cells and thus to decrease tumor burden and extend survival time. To gain additional information on the role of Kupffer cells and their interaction with tumor cells in hepatic metastases, we studied an established experimental hematogenous metastatic model (Friend erythroleukemia) in mouse livers by light and electron microscopy. Highly activated Kupffer cells were observed in close contact with tumor cells in sinusoids and also in tumor forming foci within the hepatic parenchyma. The Kupffer cells were activated by the presence of the hematogenous tumor cells and were able to lyse and phagocytose them. However, some tumor cells evaded the Kupffer cells as metastases still occurred. Kupffer cells and other macrophages were found to leave the sinusoids and migrate to sites of potential tumor development where they interacted with tumor cells and intimately wrapped their processes around fat storing cells. It is possible that these macrophages which cross biological barriers could be used to deliver drug-loaded microparticles (liposomes and microcapsules) to tumors.

Hyperplastic lesions of the gingiva and alveolar mucosa. A study of 175 cases

175 'epulides' were studied clinically and histologically. The lesions were histologically reclassified into three groups: granulomatous, fibromatous and giant cell lesions. The granulomatous group was four times and the giant cell group 1.5 times more frequent in females. It is suggested that the expression epulis should be abandoned as a microscopic designation for lesions in the oral mucosa, as it is only a non-specific topographico-clinical concept comprising histogenetically and histomorphologically differing lesions and therefore does not represent a uniform group. The suggested new terms for the three types of hyperplastic lesions are oral mucosal granulomatous hyperplasias (including such diagnostic terms as granulomatous gingivitis, gingivitis of pregnancy, granuloma gravidarium, pyogenic granuloma, epulis angiomatosa and epulis telangiectaticum), oral mucosal fibrous hyperplasias (including such diagnostic terms as fibrous epulis, epulis fissuratum, fibroepithelial lesions, denture injury tumor and peripheral odontogenic fibroma) and oral mucosal giant cell hyperplasia (including such diagnostic terms as peripheral giant cell granuloma and giant cell epulis).

Massive peripheral giant-cell reparative granuloma of the jaw: a pregnancy dependent tumor

The case of a pregnant patient with giant-cell granuloma is presented. Differential diagnosis and treatment are discussed and the literature is reviewed.

Electron microscopic study of peripheral giant-cell reparative granuloma

Six giant-cell tumors have been examined by electron microscopic methods in order to determine their histogenesis and to expand knowledge of cell structures. The examination of giant cells revealed an abundance of cell organelles, especially mitochondria. Apart from typical stromal cells, such as fibroblasts, macrophages, and mast cells, clusters of stromal "light" cells were often found with an intimate relation between their cell membranes. The role and function of these cells is not well known. Between fibroblasts of regular appearance with a small number of cytoplasmic organelles, others were found with an incrased number of mitochondria. These cells often formed aggregates. This suggests that giant cells develop through the association of stroma fibroblast cells.