Pathomorphologic study on macrophages in hepatocellular carcinoma

Sixty-eight surgical cases of hepatocellular carcinoma (HCC) were examined by light and electron microscopy for macrophages in the cancerous tissues. Macrophages were demonstrated in the blood spaces of cancerous tissues in 63 (92.6%) of 68 HCCs by light microscopy and in 16 (88.9%) of 18 HCCs by electron microscopy. Macrophages were most frequent in well-differentiated HCCs with a thintrabecular pattern. Well-differentiated HCC seemed to contain more macrophages than poorlydifferentiated one. In most cases, the number of macrophages in the cancerous tissue was fewer than that of Kupffer cells in the surrounding liver tissue. On the other hand, hyperplastic nodules and focal nodular hyperplasias contained macrophages as well, and the number of macrophages in these nodules was greater than or similar to the Kupffer cells in the surrounding liver tissue. The pattern of localization in the blood spaces, morphological features including the presence of abundant lysozyme and D-PAS activity suggested that the macrophages in the cancerous tissue might be the same as the Kupffer cells.