Ovarian torsionThis patient presented with acute right lower quadrant pain. The actual diagnosis was ovarian torsion.患者表现为突发右下腹剧痛，正确诊断为卵巢扭转。
Findings and Diagnosis
FindingsCT with IV contrast demonstrates a large, heterogeneous mass within the pelvis, which appears to arise from the right adnexa. When compared with noncontrast CT images from an outside hospital 24 hours prior, there was no significant contrast enhancement. There is stranding of the surrounding fat with free fluid, increased from the prior study. There was a normal appearance of the appendix.CT平扫及增强扫描示：盆腔内巨大不均质肿块，来源于右侧附件。与外院24小时前的CT平扫片相比，增强后病灶无明显强化，且病灶周围脂肪间隙内渗出性改变有所增加。阑尾未见明显异常。Differential Diagnosis
Ovarian torsion 卵巢扭转
Soft-tissue sarcoma 软组织肉瘤
Appendicitis 阑尾炎
Teratoma/yolk sac tumor 畸胎瘤/卵黄囊瘤
DiagnosisOvarian torsion卵巢扭转
Key Points
Ovarian torsion is the rotation of the ovarian vascular pedicle, which causes vascular obstruction.卵巢扭转是指卵巢的血管窦扭转，引起血管梗阻。
Imaging may show peripheral cysts as ovary gets congested and follicles fill with fluid.由于卵巢充血水肿、液体进入滤泡，影像上表现为卵巢周围多发囊性区。
Free peritoneal fluid or blood also may be seen.有时可见腹膜后积液或积血。
There is a lack of enhancement of ovarian stroma with thickening of the fallopian tube.增强扫描卵巢基质无明显强化，输卵管增粗。
In adults, there is usually an underlying structural abnormality. However, in the pediatric population, the ovary is usually normal.成人卵巢扭转一般有卵巢的结构异常基础，而儿童患者，卵巢常常是正常的。
Mean age is 10-11, with 50% of cases being in premenarchal girls.平均发病年龄10-11岁，约50%的患者发生于月经初潮前。
Presents as acute or intermittent abdominal pain, often with nausea and vomiting.临床表现为急性或间歇性腹痛，多伴有恶性、呕吐。
Key differential from imaging and/or clinical standpoints is appendicitis, ureteral stone, benign or malignant ovarian neoplasm, and ectopic pregnancy.影像学主要鉴别诊断包括阑尾炎、输尿管结石、良性或恶性卵巢肿瘤、移位妊娠。
