Comparative analysis of human omental milky spots between the patients with colon cancer and the control group

Morphological description of milky spots (MSs) in the human greater omentum.

Samples of the greater omentum collected during surgical procedures were subjected to further histological analysis. Two groups of patients were studied. Group A consisted of patients with colon cancer and peritonitis (stimulated MSs), group B consisted of patients without colon cancer and without peritonitis (unstimulated MSs). In the research, we focused on the cellular composition and differences between stimulated and unstimulated MSs.

MSs detected in the study were predominantly oval (67 %), round (12 %) or irregular in shape (21 %). The average number of immune cells found in one milky spot (MS) in the group A was 454 (209-694), consisted of T cells in 44.7 % (27-55 %), B cells in 26.8 % (16-34 %), macrophages in 18.3 % (12-27 %) and other immune cells in 10.2 % (6-18 %). The average number of immune cells found in one MS in the group B was 58 (42-100 %), consisted of T cells in 21.1 % (16-22 %), B cells in 18.7 % (13-22 %), macrophages in 46.9 % (33-60 %) and other immune cells in 13.3 % (1-22 %). The average size of MSs in the group A was significantly higher than in the group B: 768 μm (313-1075) to 293 μm (197-421). The results showed that there were significant differences in terms of strong predominance of macrophages in unstimulated milky spots and strong predominance of T cells in stimulated milky spots.

MSs are specific immune active lymphatic structures on the greater omentum. They play a key role in defense mechanism, especially in peritonitis. Their function is not completely clear in cancer, some authors suggest they might play a significant role in omental metastasis. Further analysing of the morphology and cells interactions of MSs is needed (Tab. 2, Fig. 6, Ref. 20).