Peritoneal metastases appear in a great proportion of patients affected by gastric carcinoma. Involved mechanisms are poorly understood though experimentally it has been demonstrated that neoplastic cells exfoliated from primary tumor can only implant and proliferate in areas of damaged peritoneum. Objectives: to study ultra-structure of peritoneal surface by electronic microscopy in control subjects and in patients with early or locally advanced gastric cancer looking for spontaneous changes in peritoneal surface not related with surgical injury.

18 out of 32 cases were eligible for analysis. Four patients operated on for benign diseases served as control and 14 patients with operable local gastric adenocarcinoma (4 mucosa/submucosa/muscular y 10 serosa lesions) were studied. At the beginning of surgery, a 2 x 2 cm. sample from macroscopically normal visceral peritoneum at mesenterium root was carefully obtained, washed with saline and fixed in glutaraldehyde solution. Besides a sample of peritoneal washing fluid was studied to exclude patients with free cancer cells. Peritoneal tissue was fixed during 24 hours and then all samples were evaluated by electronic microscope.

Inclusion Criteria:

• patients with operable local gastric adenocarcinoma

Exclusion Criteria:

• previous abdominal surgery
• previous open or blunt abdominal trauma
• history of inflammatory bowel disease or Typhoid Fever, Gallstone disease, chemotherapy or radiotherapy, or any other abdominal condition that could alter peritoneal integrity.
• All other gastric malignancies such as lymphomas, GIST, carcinoids

patients with operable local gastric adenocarcinoma consulting to Hospital Clinico, University of Chile during study period.