What is the pathophysiology of epithelial ovarian cancer?

Updated: Aug 10, 2020
  • Author: Andrew E Green, MD; Chief Editor: Yukio Sonoda, MD  more...
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Epithelial ovarian cancer is thought to arise from epithelium covering the fimbria of the fallopian tubes, or the ovaries, both of which are derived from the coelomic epithelium in fetal development. This coelomic epithelium is also involved in formation of the müllerian ducts, from which the fallopian tubes, uterus, cervix, and upper vagina develop.

Four main histologic subtypes, which are similar to carcinoma, arise in the epithelial lining of the cervix, uterus, and fallopian tube, as follows:

  • Serous (from fallopian tube)
  • Endometrioid (endometrium)
  • Mucinous (cervix)
  • Clear cell (mesonephros)

Some variation is observed in the patterns of spread and disease distribution within the various histologic subtypes.

Epithelial tumors are found as partially cystic lesions with solid components. The surface may be smooth or covered in papillary projections (see the image below), and the cysts contain fluid ranging from straw-colored to opaque brown or hemorrhagic.

An enlarged ovary with a papillary serous carcinom An enlarged ovary with a papillary serous carcinoma on the surface.

Epithelial ovarian cancer most often spreads initially within the peritoneal cavity (see the image below). Metastatic disease often is found on the peritoneal surfaces, particularly on the undersurface of the diaphragms, the paracolic gutters, the bladder, and the cul-de-sac. Other common sites are as follows:

  • Surface of the liver
  • Mesentery and serosa of the large and small bowel
  • Omentum
  • Uterus
  • Para-aortic and pelvic lymph nodes
Metastases from epithelial ovarian carcinoma invol Metastases from epithelial ovarian carcinoma involving the omentum.

Outside the peritoneal cavity, epithelial ovarian cancer may spread to the pleural cavity, lungs, and groin lymph nodes. The presence of pleural effusion does not necessarily indicate disease in the chest, and malignancy can be diagnosed only cytologically. Mucinous tumors tend to form large dominant masses, while papillary serous tumors have a more diffuse distribution and are more commonly bilateral. Endometrioid and clear-cell variants more commonly exhibit local invasion, retroperitoneal disease, and hepatic metastases.

Increasing evidence suggests that a high proportion of high-grade serous carcinoma originates from distal fallopian tube epithelium or the tuboperitoneal junction rather than the ovarian surface epithelium. Serous intraepithelial or early invasive carcinoma has been found in up to 10% of fallopian tubes from BRCA mutation carriers who had undergone prophylactic bilateral salpingo-oophorectomies. Clinical, molecular, and genetic studies, as well as in vitro and animal models, have also supported a tubal origin for high-grade serous ovarian carcinoma. [9, 10]

Those findings have prompted the suggestion that prevention of ovarian cancer in selected women at high risk could be better accomplished with salpingectomy. A study comparing standard risk-reducing salpingo-oophorectomy with the combination of early risk-reducing salpingectomy and delayed oophorectomy in BRCA carriers is currently recruiting participants. [11]

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