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| {{CMG}}{{AE}} {{MD}} | | {{CMG}}{{AE}} {{MD}} |
| Ultrasound dysgerminomas May be seen as a septated ovarian mass with varying echotexture. Colour Doppler interrogation may show prominent flow signal within the fibrovascular septa 2. | | Ultrasound dysgerminomas |
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| CT
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| Calcification may be present in a speckled pattern. Characteristic imaging findings include multilobulated solid masses with prominent fibrovascular septa. Post contrast imaging can often show enhancement of the septae.
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| MRI | | MRI |
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| Mature (cystic) ovarian teratomaMay show calcific and tooth components with the pelvis. | | Mature (cystic) ovarian teratomaMay show calcific and tooth components with the pelvis. |
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| Pelvic ultrasound
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| Ultrasound is the preferred imaging modality. Typically an ovarian dermoid is seen as a cystic adnexal mass with some mural components. Most lesions are unilocular.
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| The spectrum of sonographic features includes:
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| diffusely or partially echogenic mass with posterior sound attenuation owing to sebaceous material and hair within the cyst cavity echogenic interface at the edge of mass that obscures deep structures: the tip of the iceberg sign
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| mural hyperechoic Rokitansky nodule: dermoid plug echogenic, shadowing calcific or dental (tooth) components presence of fluid-fluid levels 5 multiple thin, echogenic bands caused by hair in the cyst cavity: the dot-dash pattern colour Doppler: no internal vascularity internal vascularity requires further workup to exclude a malignant lesion
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| CT
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| CT has high sensitivity in the diagnosis of cystic teratomas 6 though it is not routinely recommended for this purpose owing to its ionising radiation.
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| Typically CT images demonstrate fat (areas with very low Hounsfield values), fat-fluid level, calcification (sometimes dentiform), Rokitansky protuberance, and tufts of hair. The presence of most of the above tissues is diagnostic of ovarian cystic teratomas in 98% of cases 5. Whenever the size exceeds 10 cm or soft tissue plugs and cauliflower appearance with irregular borders are seen, malignant transformation should be suspected 5.
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| When ruptured, the characteristic hypoattenuating fatty fluid can be found as antidependent pockets, typically below the right hemidiaphragm, a pathognomonic finding 2. The escaped cyst content also leads to a chemical peritonitis and the mesentery may be stranded and the peritoneum thickened, which may mimicperitoneal carcinomatosis 2.
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| Pelvic MRI | | Pelvic MRI |
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| Immature ovarian teratoma | | Immature ovarian teratoma |
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| The imaging appearance is typically of a large, heterogeneous mass with a prominent solid component. However, the spectrum of appearances ranges from a predominatly cystic to a predominantly solid mass. Immature teratomas tend to be larger than mature cystic teratomas at initial presentation.
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| Extension through the tumour capsule may be present.
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| Immature teratoma may metastasise to peritoneum, liver or lung. Metastasis to brain has also been reported 7.
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| Pelvic ultrasound
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| Ultrasound appearance can be as a heterogeneous adnexal mass although is non-specific. Calcifications may be present.
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| CT and MRI | | CT and MRI |
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| Ovarian yolk sac tumour | | Ovarian yolk sac tumour |
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| General
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| The tumour typically manifests as a large, complex pelvic mass that extends into the abdomen and contains both solid and cystic components. The cystic areas are composed of epithelial lined cysts produced by the tumour or of co-existing mature teratomas. Bilaterality is rare.
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| Pelvic ultrasound
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| Tends to have both echogenic and hypoechoic components 4.
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| Pelvic MRI | | Pelvic MRI |
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]Associate Editor(s)-in-Chief: Monalisa Dmello, M.B,B.S., M.D. [2]
Ultrasound dysgerminomas
MRI
Tumours are often seen divided into lobules by septa.
Reported signal characteristics include:
T2: the septae are often hypointense or isointense 3 T1 C+ (Gd): the septae often show marked enhancement 3
Conventional radiography
Mature (cystic) ovarian teratomaMay show calcific and tooth components with the pelvis.
Pelvic MRI
MR evaluation usually tends to be reserved for difficult cases, but is exquisitely sensitive to fat components. Both fat suppression techniques and chemical shift artefact can be used to confirm the presence of fat.
Enhancement is also able to identify solid invasive components, and as such can be used to accurately locally stage malignant variants.
Immature ovarian teratoma
CT and MRI
The presence of a prominent solid component containing calcifications and small foci of fat is suggestive. Cystic components may contain serous, mucinous, or fatty sebaceous material. Haemorrhage may be present.
Ovarian yolk sac tumour
Pelvic MRI
They can be associated with prominent signal voids on MRI 2. Areas of haemorrhage can also be seen.
Ovarian choriocarcinoma On imaging, choriocarcinomas appear as vascular solid tumours with cystic, haemorrhagic, and necrotic areas.
References
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