Paraovarian cysts (POCs) are remnants of Wolffian duct in the mesosalpinx that do not arise from the ovary. They account for ~10-20% of adnexal masses 3-4.
They typically occur in women at the ages of 20-40 years old.
Most are asymptomatic, although patients with large lesions can present with pelvic pain.
They usually occur around the broad ligament and arise from paramesonephric, mesothelial, or mesonephric remnants. They are usually simple cysts (although some authors include paraovarian cystadenomas under the umbrella of paraovarian cysts).
A paraovarian cyst is easier to recognise if the ipsilateral ovary is demonstrated to be separate from it.
- typically thin-walled and smoothly marginated
- most often appear as unilocular 'simple' cysts (in ~66%) and rarely as multilocular (~4%)
- a soft tissue nodule in the cyst may indicate the development of a neoplasm (rare) 9
Often seen located close to the ipsilateral round ligament and are often of homogenous signal intensity.
In uncomplicated cases, signal characteristics usually follow that of fluid 12.
- can be hyperintense if complicated by haemorrhage
Other features include
- may show a beak sign 11
Treatment and prognosis
Paraovarian cysts occasionally can be complicated by rupture, torsion, or hemorrhage. Large or symptomatic cysts often undergo surgical resection. Smaller asymptomatic ones are treated conservatively.
For simple paraovarian cysts with no suspicious features on ultrasound, follow-up recommendations are the same as for ovarian cysts. According to a consensus statement by the Society of Radiologists in Ultrasound 13, follow-up is recommended for cysts that are:
- 5 to 7 cm in a woman of reproductive age
- 1 to 7 cm in a postmenopausal woman
Irrespective of age, cysts larger than 7 cm warrant further evaluation (with MRI) or surgical review.
History and etymology
Paraovarian cysts are also sometimes referred to as paratubal cysts or hydatid cysts of Morgagni 14,
For an adnexal cystic lesion consider:
- 1. Gopal K, Lim Y, Dobson M et-al. A case of torted parafimbrial cyst on MRI: case report and review of the literature. Br J Radiol. 2006;79 (948): e208-10. doi:10.1259/bjr/23068987 - Pubmed citation
- 2. Adusumilli S, Hussain HK, Caoili EM et-al. MRI of sonographically indeterminate adnexal masses. AJR Am J Roentgenol. 2006;187 (3): 732-40. doi:10.2214/AJR.05.0905 - Pubmed citation
- 3. Kier R. Nonovarian gynecologic cysts: MR imaging findings. AJR Am J Roentgenol. 1992;158 (6): 1265-9. AJR Am J Roentgenol (citation) - Pubmed citation
- 4. Athey PA, Cooper NB. Sonographic features of parovarian cysts. AJR Am J Roentgenol. 1985;144 (1): 83-6. AJR Am J Roentgenol (abstract) - Pubmed citation
- 5. Barloon TJ, Brown BP, Abu-yousef MM et-al. Paraovarian and paratubal cysts: preoperative diagnosis using transabdominal and transvaginal sonography. J Clin Ultrasound. 24 (3): 117-22. doi:10.1002/(SICI)1097-0096(199603)24:3<117::AID-JCU2>3.0.CO;2-K - Pubmed citation
- 6. Alpern MB, Sandler MA, Madrazo BL. Sonographic features of parovarian cysts and their complications. AJR Am J Roentgenol. 1984;143 (1): 157-60. AJR Am J Roentgenol (abstract) - Pubmed citation
- 7. Moyle PL, Kataoka MY, Nakai A et-al. Nonovarian cystic lesions of the pelvis. Radiographics. 30 (4): 921-38. doi:10.1148/rg.304095706 - Pubmed citation
- 8. Brown DL, Dudiak KM, Laing FC. Adnexal masses: US characterization and reporting. Radiology. 2010;254 (2): 342-54. doi:10.1148/radiol.09090552 - Pubmed citation
- 9. Kim JS, Woo SK, Suh SJ et-al. Sonographic diagnosis of paraovarian cysts: value of detecting a separate ipsilateral ovary. AJR Am J Roentgenol. 1995;164 (6): 1441-4. AJR Am J Roentgenol (abstract) - Pubmed citation
- 10. Korbin CD, Brown DL, Welch WR. Paraovarian cystadenomas and cystadenofibromas: sonographic characteristics in 14 cases. Radiology. 1998;208 (2): 459-62. Radiology (abstract) - Pubmed citation
- 11. Kishimoto K, Ito K, Awaya H et-al. Paraovarian cyst: MR imaging features. Abdom Imaging. 27 (6): 685-9. doi:10.1007/s00261-002-0014-6 - Pubmed citation
- 12. Imaoka I, Wada A, Kaji Y et-al. Developing an MR imaging strategy for diagnosis of ovarian masses. Radiographics. 26 (5): 1431-48. doi:10.1148/rg.265045206 - Pubmed citation
- 13. Levine D, Brown DL, Andreotti RF et-al. Management of asymptomatic ovarian and other adnexal cysts imaged at US: Society of Radiologists in Ultrasound Consensus Conference Statement. Radiology. 2010;256 (3): 943-54. doi:10.1148/radiol.10100213 - Pubmed citation
- 14. Rezvani M, Shaaban AM. Fallopian tube disease in the nonpregnant patient. Radiographics. 31 (2): 527-48. doi:10.1148/rg.312105090 - Pubmed citation
Ultrasound - gynaecology
- ultrasound (introduction)
- acute pelvic pain
- chronic pelvic pain
- Mullerian duct anomalies
- ovarian follicle
- ovarian torsion
- pelvic inflammatory disease
- ovarian cysts and masses
- ovarian cyst
- corpus luteum
- haemorrhagic ovarian cyst
- ruptured ovarian cyst
- ovarian epithelial tumours
- granulosa cell tumours of the ovary
- paraovarian cyst
- polycystic ovaries
- ovarian hyperstimulation syndrome
- post-hysterectomy ovary
- fallopian tube