Preliminary Diagnosis: Teratoma
I. What imaging technique is first-line for this diagnosis
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Transabdominal or transvaginal ultrasound of the abdomen and pelvis.
II. Describe the advantages and disadvantages of this technique for diagnosis of teratoma.
Advantages
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Well-validated and well-investigated sonographic features that are diagnostic for teratomas.
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High sensitivity and very high positive predictive value (100%) when adnexal mass has 2 or more sonographic features known to be associated with teratomas.
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Cheap and easily accessible.
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Does not require use of ionizing radiation, and safe in pregnancy and children.
Disadvantages
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Operator- and viewer-dependent.
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Certain radiographic features may have overlap with other ovarian conditions, such as endometrioma.
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Teratomas often have sonographic features that suggest a solid component, which may be mistaken for a solid ovarian mass and suggest malignancy.
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Unable to fully assess for loco-regional or metastatic disease if malignant.
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Limited view in obese patients or in patients with unusual abdominal anatomy.
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Unclear whether transvaginal or transabdominal US is better to assess.
III. What are the contraindications for the first-line imaging technique?
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There are no major contraindications to ultrasound of the abdomen/pelvis.
IV. What alternative imaging techniques are available?
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CT of the abdomen and pelvis with IV contrast
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MRI of the abdomen and pelvis with IV contrast
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FDG-PET.
V. Describe the advantages and disadvantages of the alternative techniques for diagnosis of teratoma.
CT of the abdomen and pelvis with IV contrast
Advantages
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Excellent sensitivity for detection of fat and calcifications, which are present in most teratomas.
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May be more beneficial in assessing other less common teratoma sub-types such as immature cystic and monodermal teratomas.
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May provide better anatomy and characterization of teratoma and, if malignant, assess for loco-regional and/or metastatic spread.
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Not operator-dependent.
Disadvantages
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More expensive than ultrasound.
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Limited ability to identify teratomas if fat not present.
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Involves exposing the patient to ionizing radiation.
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Involves the use of iodinated contrast.
MRI of the abdomen and pelvis with IV contrast
Advantages
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Highly sensitive for identifying fat and calcifications, which are present in most teratomas.
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Use of different MRI techniques increases the ability to distinguish fat (teratoma) from hemorrhagic cysts (endometrioma).
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Better visualization of the anatomy of the teratoma and surrounding tissue. If malignant, better able to assess for local and metastatic spread.
Disadvantages
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Requires the use of IV contrast.
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Expensive
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Limited accessibility in certain medical centers.
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Not well-tolerated in obese patients, claustrophobic patients, or those with inability to hold breath.
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Time-consuming
FDG-PET
Advantages
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There are no advantages to the use of PET versus the imaging modalities described above.
Disadvantages
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Expensive and not easily accessible.
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Not well-studied or well-validated.
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Limited in its ability to distinguish malignant processes from inflammatory conditions.
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No reports on the behavior of teratomas with FDG-PET scanning.
VI. What are the contraindications for the alternative imaging techniques?
CT of the abdomen and pelvis with IV contrast
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Contraindicated in pregnant patients
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Contraindicated in patients with iodine allergies
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Contraindicated in patients with renal insufficiency
MRI of the abdomen and pelvis with IV contrast
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Contraindicated in patients with pacemakers, and patients with other implantable, MRI-incompatible devices
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Contraindicated in patients with chronic renal failure.
FDG-PET
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There are no major contraindications to this imaging modality.
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