Reporting of the precise diagnosis of adnexal masses is an important issue in clinical practice, as inaccurate diagnosis might lead to unnecessary examinations and surgeries, and appropriate diagnosis improves the communication between the medical team and leads to better outcome [19, 20].
This study detected the clinical usefulness of ultrasound reporting system GI-RADS in the diagnosis of adnexal masses after evaluating different criteria. The prevalence of malignant lesions was 29.5%. Malignant lesions were more likely to show thick walls, thick septa, papillary projections, solid areas, and central blood flow. Postmenopausal patients had higher incidence of malignant lesions while in premenopausal patients, most lesions were benign. In our study, we had one postmenopausal patient classified as GI-RADS 2, the lesion showed regressive course on follow-up ultrasound examination. Postmenopausal women may present with functional or simple ovarian cysts that could be detected by ultrasound examination, saving surgical intervention and unnecessary imaging studies. The presence of functional or simple ovarian cysts in such age group was due to the residual ovarian activity [21].
Our results came in consistency with the study done by Zhang and colleagues who conducted a retrospective study over 263 adnexal masses and concluded that thick wall, solid papillary projections, solid areas, and central blood flow were associated with malignant lesions. The sensitivity and specificity of GI-RADS were 96.4% and 84.3%, respectively [22].
The 112 lesions were distributed by GI-RADS classification as the following: 36 (32.1%) GI-RADS 2, 32 (28.6%) GI-RADS 3, 13 (11.6%) GI-RADS 4, and 31 (27.7%) GI-RADS 5. The ovarian neoplastic lesions represented 55 lesions (49%) of the total number of the detected lesions in our study. The diagnostic accuracy of GI-RADS classification in the assessment of ovarian neoplastic lesions according to ultrasound findings and guided by the histopathological classification were 97%, 73%, 84%, 94%, and 87% for sensitivity, specificity, PPV, NPV, and accuracy, respectively.
The present study included one false-negative and twelve false-positive lesions. The false-negative lesion was misclassified as GI-RADS 3, as there was no ultrasound findings suggestive of malignancy. The histopathological diagnosis was serous cystadenocarcinoma. This was similar to a study done by Migda et al, who found two malignant lesions out of 119 lesions categorized as GI-RADS 1–3 [23].
The twelve false-positive lesions included 6 benign ovarian neoplastic lesions, one case with ovarian torsion-detorsion, one endometrioma lesion with atypical ultrasound findings, two tubo-ovarian complex, and two pedunculated subserous fibroids. In case of ovarian torsion-detorsion misclassified as GI-RADS 5, the patient presented with vague clinical picture and there was no definite history of acute pain. The ultrasound examination revealed a large highly vascular ovary, but on follow-up ultrasound examination, there was regression in the ovarian size and vascularity.
The endometrioma lesion was misclassified as GI-RADS 4 in our study due to the atypical ultrasound findings: multilocular cystic lesion with suspected solid component. Regarding the two tubo-ovarian lesions, there was no recent history of pain or fever; borderline ovarian tumours were considered as a differential diagnosis. This agrees with the previous studies suggesting that about 50% of female patients presenting with chronic tubo-ovarian abscesses may have normal body temperature and nonspecific clinical symptoms including vaginal discharge, abnormal vaginal bleeding, or mild abdominal pain. These clinical signs and symptoms may mimic borderline or malignant ovarian tumours. In such cases, further assessment by pelvic MRI examination for better characterization of the lesions is recommended [24, 25].
In the current study regarding the diagnosis of neoplastic lesions, we had 22 benign lesions and 33 malignant lesions. The GI-RADS classification rates in GI-RADS 4 were 5 benign neoplastic lesions (false positive) and 3 malignant lesions. In GI-RADS 5, there were 29 malignant lesions and one benign neoplastic lesion (false positive). The specificity was 73%. This agrees to a great extent with the study done by Migda et al. [23], who reported 45 benign and 50 malignant lesions. In the GI-RADS 5 group, there were only malignant lesions while in the GI-RADS 4 group, there were about 45 benign lesions (false-positive lesions) and the specificity of the study was 72%. The false-positive lesion misclassified as GI-RADS 5 in our study due to the solid appearance and the increased vascularity of the lesion was diagnosed as fibrothecoma benign by histopathology.
The present study also agrees with a study done by Amor et al. [12], who reported that no malignant lesion was classified as GI-RADS 2 and one malignant lesion (false negative) was misclassified as GI-RADS 3. Amor et al. [12] found that the prevalence of malignant lesions was 26%. Their lesions were classified by GI-RADS as follows: 92 (21%) GI-RADS 2, 184 (43%) GI-RADS 3, 40 (9%) GI-RADS 4, and 116 (27%) GI-RADS 5, and the sensitivity of the system was 99.1%, specificity 85.9%, PPV 71.1%, and NPV 99.6%.
It is also worth pointing out that GI-RADS reporting system will be of great use as it enhances communication between radiologists and gynaecologists for better diagnosis and proper management of the patients presenting with adnexal lesions based on clinical and ultrasound morphological characteristics of the lesion [12].