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Ovarian mature cystic teratoma - doughnut sign

Case contributed by Hazem M Almasarei
Diagnosis almost certain

Presentation

Lower abdominal pain

Patient Data

Age: 40 years
Gender: Female

There is a well-defined and heterogeneous echo pattern cyst/mass located in the left adnexal region and mostly arising from the left ovary, it measuring 6 x 8 x 7 cm, it characterized by hypoechogenicity, containing well-circumscribed echogenic component measuring 5 x 5 cm and internal echogenic debris. There is no definite vascularity on color Doppler. Features are likely complex left ovarian cyst.

The whole left ovary is hugely enlarged, measures approximately 8.6 x 7.6 x 10.4 cm. There is a large heterogeneous soft tissue mass lesion, as the following: The major component is fat intensity (which appears bright in T1, T2 and suppressed in STIR and T1 FAT SAT). There is a target-like (doughnut sign) lesion measuring 5.7 x 6.8 x 5.7 cm, it shows hypointense on T1 (containing dots of hyper signal intensity), intermediate signal on T2 and hyperintense STIR sequences. It shows restriction diffusion on DWI, which may suggest Rokitansky nodules. There is no significant enhancement after IV contrast administration. Features are representing ovarian dermoid cyst/ mature cystic teratoma.

Annotated image

Doughnut / Donut sign

Case Discussion

Mature cystic teratoma is also known as a dermoid cyst, its the most common benign ovarian tumor in women with the age of 40. It composed of at least 2 of 3 embryonic germ cell layers, so these lesions are different in imaging modality according to its component especially on MRI that gives different intensities. It contains fat, skin component, hair follicles, fluid and calcification. It sometimes contains projecting nodules within the lesion known as Rokitansky nodule and it might take different shapes and sizes, like this case, it takes the shape of a doughnut.

Acknowledgment:

Dr Koulshan Mohammad Jameel Specialist Obstetrics & Gynecology, MBCHB, DGO, MRCOG, Fellowship in Cosmetic Gynecology.

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