What is the role of imaging studies in the workup of cystic teratoma?

Updated: Nov 22, 2019
  • Author: Chad A Hamilton, MD; Chief Editor: Yukio Sonoda, MD  more...
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Answer

The workup for cystic teratomas is largely radiographic, and their appearance is similar despite varying locations.

If the teratoma is recognized in utero, the fetus should undergo serial ultrasound surveillance for development of fetal hydrops. Amniotic fluid volume and placental thickness should be evaluated as early markers for hydrops. Tumor growth rate and vascular flow through solid portions may help assess fetal risks. In the case of sacrococcygeal teratomas, an ultrasound examination may demonstrate extension of the tumor into the pelvis or abdomen and possible displacement of the bladder and rectum, with compression of the ureters resulting in hydroureter or hydronephrosis. [43, 23]

Fetal magnetic resonance imaging (MRI) likely provides the most accurate assessment of anatomical extent and impact, with excellent resolution regardless fetal orientation, maternal obesity, oligohydramnios, or shadowing from the bony pelvis, which may limit ultrasound visualization. [24] Computed tomography (CT) scanning of the abdomen and pelvis before surgical exploration can further delineate sacrococcygeal tumor from normal anatomic features. [9]

Ultrasonography with adjunctive CT scanning is useful in imaging suspected ovarian teratomas and may detect liver and retroperitoneal lymph node involvement in malignant cases. Ultrasonic findings ascribed to teratomas include the following [44]  :

  • Shadowing echo densities
  • Regionally bright echoes
  • Hyperechoic lines and dots
  • Fluid-fluid levels

In a study by Mais et al, transvaginal ultrasonography had a sensitivity and specificity of 84.6% and 98.2%, respectively, for differentiating cystic teratoma from other ovarian masses. [45] In another trial, Patel et al demonstrated a 98% positive predictive value and 85% sensitivity using ultrasound to diagnose and identify cystic teratomas. [40]

CT scan usually reveals the complex appearance of ovarian teratomas, with dividing septa, internal debris, fat attenuation (93%), and distinct calcification (56%). [44]

MRI can sufficiently differentiate lipid density from other fluid and blood and may be another useful adjunct for diagnosis of ovarian teratomas, with an accuracy of 99%. [46]

When a testicular mass is detected on prenatal ultrasound or postnatally as a palpable nodule or as volumetric increase in the scrotum, ultrasound may be the most useful adjunct test. Testicular teratomas have a varied ultrasound appearance, which may include solid and cystic elements, septations, calcifications, and rare vascularity. Despite this, evaluation before surgical treatment may aid in decisions regarding testis-sparing enucleation or excision. [47]

In the case of a suspected mediastinal teratoma, anterior-posterior and lateral chest radiographs provide important information as to size and location of the mass. [48]

CT scan and/or MRI may further clarify the diagnosis and also are invaluable in delineating the boundaries of mediastinal masses, potential vascular involvement, and respectability. [48, 49]

Echocardiography can be used to delineate physiologic effects of mediastinal masses, such as tamponade or pulmonary stenosis, and may be used to guide needle biopsy. [41]


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