Endometriosis, a disease in which the endometrial structure settles where it should not be, is also known as the chocolate cyst. The endometrium can be described as the structure that lines the inside of the uterus, acts as a bed for the egg being fertilised each month and is shed through menstrual bleeding when pregnancy does not occur. Under normal conditions this structure is found only inside the uterus, but depending on various factors it can settle in areas outside the uterus and give rise to endometriosis, which can cause different health problems.
Patients with endometriosis, which shows itself with different symptoms, should never neglect their regular check-ups throughout life, and a follow-up and treatment plan should be set for each patient individually.
How Is Endometriosis Diagnosed?
Endometriosis is considered one of the diseases that are difficult to diagnose. To reach a diagnosis, the doctor first takes a detailed history and listens to the patient’s complaints. A gynaecological examination and an ultrasound scan are performed. Pain, tenderness and restricted mobility of the uterus and ovaries found during the pelvic examination are findings that can suggest endometriosis.
Blood tests are among the auxiliary methods in the diagnosis of endometriosis, and the most frequently requested are CA-125 and HE-4. These tests are not requested routinely. Since they do not allow a direct diagnosis of the disease, the doctor can request them only as additional tests. The CA-125 value is typically high.
Both the national guideline (the Endometriosis and Adenomyosis Association) and the European society of reproductive medicine (ESHRE) do not recommend measuring CA-125, because the value will be high anyway, a high value will distress the patient further and it will not change the treatment. HE-4, on the other hand, can help distinguish whether a cystic mass in the ovary is benign or malignant. HE-4 can sometimes also be raised in the borderline lesions.
Although magnetic resonance imaging (MRI) can be useful when pelvic tissue is involved, it is important that the images are interpreted by an experienced radiologist. While chocolate cysts in the ovary are easily recognised on MRI, deep endometriosis lesions can typically be missed.
The definitive diagnosis of endometriosis is made by laparoscopy, which also allows the stage to be assessed. Today, however, operating on patients with endometriosis for diagnosis alone is frequently avoided.
How Does Endometriosis Look on Ultrasound?
On ultrasound, endometriosis resembles many other cysts and can most often be confused with the ovarian cysts called haemorrhagic cysts that are about to rupture. In some cases large endometriosis cysts can resemble the appearance of ovarian cancer and are easily recognised, especially on ultrasound. Large chocolate cysts can also be imaged clearly on ultrasound.
Thanks to ultrasound imaging, besides the chocolate cysts it is also possible to image the severe adhesions that form between the uterus, the ovary and the bowel, and the endometriotic nodules located in the bowel, the rectum and the bladder. Unlike the cysts in the ovary, deep endometriosis nodules appear as hard, stocky lesions that are severely painful when moved. The same appearance is seen in caesarean scar endometriosis that develops in the anterior abdominal wall after a caesarean section.
Does the Ultrasound Device Matter in the Diagnosis of Endometriosis?
While vaginal ultrasound is more effective in diagnosing endometriosis of the ovaries, the uterus and the surrounding area, abdominal ultrasound is preferred for diagnosing endometriosis located in the organs of the upper abdomen (such as caesarean scar endometriosis in the anterior abdominal wall).
With vaginal ultrasound the uterus, the ovaries and the neighbouring organs can be imaged clearly. Vaginal ultrasound can clearly detect both the chocolate cysts in the ovary and deep endometriosis lesions in neighbouring organs such as the bowel (rectum) and the bladder.
A device that gives a good image, has good resolution and allows volume and flow assessment with additional programs makes the evaluation easier during diagnosis. However, how advanced the device is comes second in importance. The most important point is that the person performing the ultrasound assessment must be trained and experienced in this subject; otherwise the diagnosis can be missed even with the best ultrasound devices.