Para-ovarian cyst (POC), also sometimes known as a para tubal cyst or a hydatid cyst of Morgagni 14, is a type of adnexal cyst that does not arise from the ovary. They account for ~10-20% of adnexal masses 3-4.
They typically occur in women ~ the 3rd to 4th decades.
Most are asymptomatic, although patients with large lesions can present with pelvic pain.
They usually occur around the broad ligament and arise from para-mesonephric, mesothelial, or mesonephric remnants. They are usually simple cysts (although some authors include para ovarian cystadenomas under the umbrella of para ovarian cysts and can complicate their definition).
A para ovarian cyst is easier to recognise if the ipsilateral ovary is demonstrated to be separate from it.
They are typically thin-walled and smoothly marginated. They most often appear as unilocular 'simple' cysts (in ~66%) and rarely as multilocular (~4%). Depending on the definition used the cysts can show a variable number of papillary projections growing from the cyst wall (unilocular-solid cysts) in ~30% of cases ref.
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.
- T1: low signal (can be high signal if complicated by haemorrhage)
- T2: high signal
Other features include
- may show a beak sign 11
Treatment and prognosis
Large or symptomatic cyst often undergo surgical resection smaller asymptomatic ones are treated conservatively.
For simple para-ovarian 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, or
- 1 to 7 cm in a post-menopausal woman
Irrespective of age, cysts larger than 7 cm warrant further evaluation (with MRI) or surgical review.
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)24:33.0.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
Synonyms & Alternative Spellings
|Synonyms or Alternative Spelling||Include in Listings?|
|Para tubal cyst||✓|
|Para ovarian cysts||✗|
|Para fimbrial cysts||✗|
|Para tubal cysts||✗|
|Para ovarian cyst (POC)||✗|
|Hydatid cyst of Morgagni||✓|
|Hydatid cysts of Morgagni||✗|
|Para fimbrial cyst||✓|
|Hydatid of Morgagni||✗|
|Hydatids of Morgagni||✗|
|Para ovarian cyst||✗|