Endometriosis is characterized by the presence of endometrial tissue outside the uterus. When endometrial implants penetrate more than 5 mm into the peritoneum, the condition is referred to as deep pelvic endometriosis. Although laparoscopy is the gold standard test to establish a diagnosis of deep endometriosis, transvaginal ultrasound represents an alternative that can contribute to detection of the disease, because it is an accessible, low-cost, noninvasive examination that allows preoperative planning in cases requiring surgical treatment. However, in clinical practice, transvaginal ultrasound is still not widely used as the first-line examination in suspected cases of endometriosis. This essay describes the findings of deep endometriosis on transvaginal ultrasound, in order to disseminate knowledge of the utility of the technique for the diagnosis of this disease.

AIMS: To describe clinical and socio-demographic features, as well as transvaginal ultrasound results, of women with endometriosis symptoms.METHODS: A prospective cross-sectional study included patients who had at least one of the following symptoms: dyspareunia, dysmenorrhea, chronic pelvic pain, infertility, and urinary or bowel cyclic symptoms. The sample comprised women treated in a private gynecology clinic located in a small city in southern Brazil, from March to November 2016. All the participants, after signed an informed consent, were subjected to clinical anamnesis, transvaginal ultrasound with bowel preparation, and examination for the CA-125 antigen serum level. Association between two qualitative variables was assessed through Pearson's Chi-Square or Fisher's exact tests. Mean values of quantitative variables were compared through the two-tailed Student's t-test for independent samples. Significance level was set as p<0.05.RESULTS: A total of 85 women, aged 18-49 years, participated in the study. Most were married (75.3%), with children (51.8%), showed no family history of endometriosis (89.4%), had no knowledge about endometriosis (77.6%) and completed high school (43.5%). Ultrasound findings suggested endometriosis in 25 (29.4%) women. Dysmenorrhea was the most prevalent symptom (88.2%), followed by dyspareunia (61.2%). In comparison to those without ultrasound signs, the patients whose ultrasound findings suggested endometriosis had an older age (37.16±6.83 years vs. 30.37±6.80 years, p<0.001) and a longer duration of symptoms (9.06±6.49 years vs. 5.27±4.79 years, p=0.004). In addition, they presented higher mean serum CA-125 antigen levels (50.07±54.05 U/mL vs. 17.71±14.09 U/mL, p=0.011). Endometriosis-compatible lesions were mainly found in the ovaries (60%) and in the rectosigmoid region (52%). The disease was confirmed in the nine cases that were subjected to videolaparoscopy.CONCLUSIONS: Transvaginal ultrasound confirmed endometriosis in about one third of symptomatic patients, who were older, had symptoms for a longer time, and had higher serum CA-125 antigen levels in comparison to those without endometriosis diagnosis based on transvaginal ultrasound. Ovaries and rectosigmoid region were the sites with the highest frequency of ultrasound signs of endometriosis.