[Ovarian Sertoli-Leydig tumor: A tricky tumor]

The value of contrast-enhanced ultrasonography in differential diagnosis of benign and malignant ovarian sex cord stromal tumors

BACKGROUND

Sex cord-stromal tumors (SCSTs) are uncommon neoplasms that are typically difficult to diagnose before surgery due to limited experience in their medical imaging. Contrast-enhanced ultrasonography (CEUS) can evaluate the microvessel density of tumors, and the microvessel density of malignant tumors is significantly greater than that of benign tumors, so this provides a method for CEUS to differentiate benign and malignant tumors.

METHODS

The CEUS diagnoses of 31 patients with pathologically confirmed SCSTs were retrospectively analyzed and compared to conventional ultrasound-based diagnoses. Based on the pathological results, the patients were divided into benign and non-benign groups. Using pathology as the gold standard, four-table data were used to evaluate the authenticity of conventional ultrasonography and CEUS.

RESULTS

Among these 31 SCST patients, only the size of the lesion and the stripy hypoenhancement on CEUS differed significantly between the benign group and the non-benign group (P<0.05). In the benign group (n=25), 22 patients showed sparse stripes of hypoenhancement, 1 showed no enhancement, and 2 showed hyperenhancement. In 5 cases of malignant SCSTs, 4 showed hyperenhancement (with non-enhanced areas inside the tumor), and 1 showed sparse strips of hypoenhancement; in 1 case of borderline SCST, the tumor showed uniform hyperenhancement. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy rate of the conventional ultrasound diagnoses for the 31 SCST patients were 52.0%, 16.7%, 72.2%, 7.7%, and 45.2%, respectively. In relation to CEUS, sparse strips of hypoenhancement or no enhancement were valuable diagnostic criteria for diagnosing benign SCSTs. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy rate of CEUS were 92.0%, 83.3%, 95.8%, 71.4%, and 90.3%, respectively. The accuracy of CEUS was higher than that of conventional US, and the difference was statistically significant (χ2=14.467, P=0.000).

CONCLUSIONS

Sparse strips of hypoenhancement or no enhancement on CEUS are the characteristic manifestations of benign SCSTs, and hyperenhancement (with a non-enhanced area observable inside the mass) may be suggestive of malignant tumors. CEUS significantly improved the differentiation of benign and malignant SCSTs.