Endosalpingiosis: Definition

Endosalpingiosis is a condition in which tissue that normally lines the inside of the fallopian tube is found somewhere else in the body. It is most often found in the pelvis, including on the surface of the ovaries, on the peritoneum (the lining of the abdominal cavity), and in nearby lymph nodes.

Endosalpingiosis is a benign (noncancerous) condition. It is also common, and it is usually discovered by chance when tissue is removed for another reason. Most people with endosalpingiosis have no symptoms from it and never know it is there. This article explains what endosalpingiosis is, why it develops, what it looks like under the microscope, and why it is important that it not be mistaken for something more serious.

What causes endosalpingiosis?

The exact cause of endosalpingiosis is not fully understood, and more than one explanation may be correct. The leading ideas are:

Displacement of fallopian tube tissue — Small fragments of the tubal lining may be shed and settle elsewhere in the pelvis, possibly during ovulation, when the surface of the ovary breaks open to release an egg.
Previous surgery — Operations involving the fallopian tubes, such as tubal ligation or removal of the tubes, may move small amounts of tissue to nearby sites.
Metaplasia — Cells lining the abdominal cavity may change into cells that look like the lining of the fallopian tube. The tissues of the female reproductive tract and the lining of the abdomen develop from the same origin early in life, which may explain why this change can happen.

Endosalpingiosis is not caused by anything a person did, and it is not an infection.

Does endosalpingiosis cause symptoms?

Most of the time, endosalpingiosis causes no symptoms at all and is found incidentally, meaning it was discovered by chance during surgery or when tissue removed for another reason was examined. Some people have reported pelvic pain, at times worse around menstruation, although it can be difficult to know whether endosalpingiosis is the cause of the pain or simply present alongside it.

Is endosalpingiosis cancer?

No. Endosalpingiosis is not cancer, and the cells involved are normal, healthy tubal-type cells that are simply in an unexpected location. It is not routinely regarded as a precancerous condition, and finding it does not mean that cancer is present or that cancer will develop.

The most important point about endosalpingiosis is that it can be mistaken for cancer. Because it forms glands in places where glands are not normally found, endosalpingiosis can resemble cancer that has spread. This is especially true when it appears inside a lymph node removed during surgery for another cancer, where it can look like metastasis. Recognizing endosalpingiosis correctly matters a great deal, because mistaking it for cancer spread could lead to a higher cancer stage being reported and to treatment a person does not need. Pathologists are aware of this pitfall and use the appearance of the cells, along with special stains when needed, to tell the two apart.

Some research has looked at whether endosalpingiosis is found more often alongside certain ovarian tumors, and this relationship is still being studied. On its own, however, endosalpingiosis is a benign finding, and any follow-up depends on the reason the surgery was done rather than on the endosalpingiosis itself.

What does endosalpingiosis look like under the microscope?

Under the microscope, endosalpingiosis appears as small glands or fluid-filled cysts lined by a single layer of epithelial cells that look just like the cells lining the fallopian tube. A characteristic feature is the presence of cilia, tiny hair-like projections on the surface of the cells that, in the fallopian tube, help move an egg along. The glands may contain clear or pale pink fluid. Importantly, the cells look normal and do not show the abnormal features (atypia) seen in cancer.

Endosalpingiosis can look similar to endometriosis, another condition in which tissue is found outside its normal location. The two are told apart by what surrounds the glands: in endometriosis, the glands resemble the lining of the uterus and are surrounded by a distinctive supporting tissue, often with evidence of old bleeding. In endosalpingiosis, the glands are lined by ciliated tubal-type cells and this supporting tissue and old blood are absent. When the distinction is difficult, or when cancer needs to be ruled out, a pathologist may order immunohistochemistry, a test using special stains that detect specific proteins. Markers such as PAX8 help confirm that the tissue comes from the female reproductive tract rather than from another type of cancer.

Does endosalpingiosis need treatment?

Endosalpingiosis usually requires no treatment. Because it is benign and most often causes no symptoms, it is typically just noted in the pathology report. When endosalpingiosis is thought to be contributing to pelvic pain, treatment is directed at the symptoms and is managed by a gynecologist. No additional cancer screening or surveillance is needed for endosalpingiosis by itself.

Questions to ask your doctor

Where in my body was the endosalpingiosis found?
Was it found in a lymph node, and if so, was cancer ruled out?
Is the endosalpingiosis related to the reason I had surgery?
Could endosalpingiosis be causing my pelvic pain?
Were any special stains needed to confirm the diagnosis?
Does this finding require any treatment or follow-up?
Does it change my risk of developing cancer in the future?