Diagnosis of adnexal torsion in the third trimester of pregnancy: a case report

The diagnosis of adnexal torsion is difficult to establish on the basis of symptoms, physical findings, or radiologic techniques. If possible, in pregnancy the diagnostic workup should avoid any risk of drug administration, and the indication for a surgical intervention needs to be severe. Between 10% and 20% of ovarian torsions are associated with pregnancy, but adnexal torsion in the third trimester is rare. We present the case of a 22-year-old female presenting with a sudden onset of severe right lower quadrant abdominal pain associated with nausea and vomiting. The presumptive diagnosis was appendicitis. Transvaginal sonography showed some free fluid in the pouch of Douglas, but could not define the accurate diagnosis. In transabdominal ultrasound, a predominantly hyperechogenic mass containing small cysts was found in the right lower abdomen. No blood flow within the mass was detected with color and power Doppler sonography. With ultrasound, the anatomic relation of the mass could not be precisely identified. Magnetic resonance imaging clearly delineated the mass, which was due to enlargement of the right ovary, with predominately hyperintense signal containing small areas with hypointense lesions in T2-weighted images, a potential sign of hemorrhagic infarction. The mesovarium was hyperintense in T2-weighted images and also enlarged. The left ovary seemed to be normal. Due to the displacement of the ovaries in the second and third trimesters, the diagnostic workup is very largely restricted when using transvaginal ultrasound. Especially in pregnancy, it is mandatory to obtain a reliable diagnosis to reduce any risk to the fetus. Our case report indicates that the combination of magnetic resonance imaging and Doppler sonography fulfills these requirements and allows for accurate and fast diagnosis of adnexal torsion.