Perivascular mast cells in advanced gastric adenocarcinomas: an electron microscopic study.

Mast cells are frequently found in close proximity to blood vessels and have been implicated in tumour angiogenesis. The aim of the present ultrastructural study was to characterize, in detail, the mutual association between mast cells and microvasculature in 9 cases of advanced gastric carcinoma. Perivascular mast cells were ultrastructurally identified as T mast cells and exhibited piecemeal degranulation, indicative of a slow release of granule-stored contents.

Eosinophil-tumor cell interaction in advanced gastric carcinoma: an electron microscopic approach.

Background: Tumor-associated tissue eosinophils have been observed in human tumors and experimental tumor models, but their function is poorly understood.

Materials And Methods: One case of intestinal-type adenocarcinoma of the stomach, mainly infiltrated by eosinophils, is studied by light and electron microscopy, focusing on the relationships between eosinophils and tumor cells and on the nature of tumor cell death.

Results: Using light microscopy, eosinophils, single or in clusters, were present both in the stroma and within neoplastic glands.

Morphological evidence of neutrophil-tumor cell phagocytosis (cannibalism) in human gastric adenocarcinomas.

The phenomenon of neutrophil-tumor cell emperipolesis or phagocytosis has been documented by light microscopy in various human carcinomas, but little is known about the cellular pathological processes and the morphological changes involved. In an attempt to clarify the nature of this phenomenon, the authors' ultrastructural studies on the relationships among neutrophils and tumor cells in human gastric carcinomas are reviewed and analyzed. At the electron microscopy level, apoptotic neutrophils were found within vacuoles of adenocarcinoma cells in 2 cases.

Prognostic value of intratumoral neutrophils in advanced gastric carcinoma in a high-risk area in northern Italy.

Several lines of evidence indicate that neutrophils act nonspecifically against tumor cells. The correlation between tumor-infiltrating neutrophils (TINs) and clinicopathological features remains unclear and deserves to be investigated. To analyze the prognostic influence of TINs in gastric carcinoma, the authors selected 273 patients with advanced gastric carcinoma who underwent gastrectomy at Cremona Hospital (Lombardia, Italy) between 1990 and 1995 and followed them for a period of 5 years.

Ultrastructural observations on the microvasculature in advanced gastric carcinomas.

The ultrastructural features associated with vascular permeability in 9 cases of advanced gastric carcinomas were studied, and compared with that of control non-neoplastic mucosa. Tumour microvasculature showed features in common with those of control mucosa, including complete basal lamina, well-developed interendothelial junctions, fenestrations and caveolae. Some tumour blood vessels showed endothelial cell swelling accompained by luminal narrowing and perivascular fibrosis.