Why the fallopian tube is most probably not the origin of serous carcinoma of the ovary. Part 3

Physiopathology. One of the most important questions we need to answer is why the majority of papillary serous carcinomas of the ovary are discovered when they are stage III involving the peritoneum and omentum. The malignant cells could reach the metastatic foci via lymphatic vessels, blood vessels, or directly by seeding the peritoneum from the ovarian surface, or, if the fallopian tube is the primary site, from the lumen of the fallopian tube. The absence of positive lymph nodes in the majority of the cases rules out the possibility of dissemination via lymphatics. Similarly, tumor cells circulating in blood should originate metastases in the lungs. But this is not the most frequent situation. The most accepted explanation for the spread of ovarian cancer in the peritoneal cavity has been trans coelomic. However, because of gravity stage II should be more frequent than stage III. Tumor cells should be equivalent to bacilli in cases of pelvic inflammatory disease. The most accepted explanation for this discrepancy, which can be found in most textbooks, is the theory of the circulation of tumor cells based on a study of Feldman in 1972. In this study, two gynecologic oncologists, and two radiotherapists, interpreted a group of cells on a microscopic slide, as tumor cells that obstructed lymphatic vessels in the diaphragm of rats. The authors concluded that the obstruction of the lymphatics was the explanation for the ascites and therefore the circulation of ascitic fluid made possible the colonization of tumor cells in different areas of the peritoneal cavity. It is difficult to understand how this theory has been accepted by gynecologic oncologists and pathologists. The following are some questionable issues about this theory:

1-The theory is based on a wrong interpretation of a microscopic slide. The cells in the lumen of the vessels most probably are lymphocytes. Below I am including an image of lymphocytes in a lymphatic vessel close to a lymph node.

2-70% of ovarian cancer patients do not have ascites, but the tumor involves the omentum and/or the diaphragm.

3-Why does this theory apply only to serous carcinoma of the ovary? It does not apply to other tumors with ascites.

4-We cannot compare the small abdominal cavity of a rat, where the cells would move horizontally, with the abdominal cavity of a woman, where the cells would need to move vertically. The woman would need to be upside down for the cells to reach the diaphragm.See diagram below.

5-Even the authors, mention in the study that: "the conclusion that lymphatic obstruction alone causes ovarian carcinomatosis ascites is attractive but unproved".

I believe that multicentricity would explain the presence of tumors in the ovary, fallopian tube and peritoneum.