We describe the imaging features of a tailgut cyst mistaken for an adnexal mass. A pelvic ultrasound in a 28-year-old woman showed a 10-cm hypoechoic left pelvic mass. Having not seen the left ovary, the radiologist concluded that the mass was an endometrioma. CT disclosed a retrorectal cystic lesion with wall calcifications and internal septa. MR confirmed the extra-ovarian location of the tumor, which was hyperintense on T2-weighted images and had an intermediate signal on T1-weighted images. Surgery revealed a retrorectal cystic hamartoma. Radiological diagnosis of a tailgut cyst requires first correct localization of the tumor and then differentiation from other retrorectal masses.

We report the sonographic findings of a rare benign ovarian tumor in a 69-year-old woman. Transvaginal ultrasonography showed a cystic multilocular lesion with a vascularized central solid portion of the left ovary. Surgery revealed an adenomatoid tumor. Adenomatoid tumors are benign lesions of mesothelial origin, usually solid in nature and rarely located in the ovaries. (c) 2005 Wiley Periodicals, Inc. J Clin Ultrasound 33:233-236, 2005.

Purpose: To describe the magnetic resonance (MR) findings in ovarian functional hemorrhagic cysts (FHC). Materials and Methods:A total of 21 patients with 22 FHC, proven by follow-up ultrasound (US) in 11 women and surgery in 10 women, had US and MR examinations within 24 hours. The study was limited to cysts with obvious an echogenic pattern. All patients had T2-weighted fast spin echo (FSE), T1-weighted spin echo (SE), and T1-weighted SE fat-suppressed sequences.Results: Four cysts (18%) were hypointense on T1-weighted-images without and with fat suppression, and hyperintense on T2-weighted-images. Five cysts (23%) were hypointense on T1-weighted images without and with fat suppression but heterogenous on T2-weighted images. Five cysts (23%) were hypointense on T1-weighted images but showed intermediate signal intensity on T1-weighted fat suppression images and heterogenous signal intensity on T2-weighted images. Two cysts (9%) were entirely intermediate on T1-weighted images. Five cysts (23%) displayed high signal intensity occupying less than 30% of the cystic content on T1-weighted images and one cyst (5%) displayed high signal intensity occupying more than 30% of the cystic content. Conclusion:Despite an obvious echogenic pattern on US, 64% of FHC were hypointense on T1-weighted images and 18% were also hyperintense on T2-weighted images. Only 36% demonstrated intermediate or high signal intensity on T1-weighted images.

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Although the extraovarian location of these neoplasms is difficult to determine preoperatively by ultrasound and MR, these imaging modalities are more reliable in predicting the histology of these rare lesions and differentiating them from simple paraovarian cysts.