Possibility of defense against colorectal tumor by foamy cells

To investigate the difference between colorectal adenocarcinomas with white spots (foamy cells) and those without white spots, clinically and histopathologically, we examined 112 cases of colorectal adenocarcinomas in this study. Thirty-two cases were diagnosed as submucosal invasive adenocarcinoma and 80 as advanced adenocarcinoma. They were classified into two groups: with white spots and without white spots. Submucosal tumors and squamous epithelial-origin tumors were excluded. In each case we looked for evidence of lymph node and liver metastases. Immunoreactive staining for macrophages, foamy cells, T cells, and B cells was also performed. We found a significant difference in the incidence of lymph node metastasis between the two groups with advanced carcinoma. White spots (foamy cells) were present at some distance from carcinoma cells. We conclude that foamy cells might have a beneficial role. From a histopathological viewpoint they can be considered a possible physical defense wall, an index of immune response activation. Clinically, it is important not to overlook any lesion.