Cystic Teratoma Workup

Updated: Nov 22, 2019
  • Author: Chad A Hamilton, MD; Chief Editor: from Memorial Sloan-Kettering - Yukio Sonoda, MD  more...
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Workup

Laboratory Studies

Elevated serum alpha-fetoprotein (AFP) and beta human chorionic gonadotropin (HCG) levels may be indicative of malignancy, as these values are within reference ranges in most patients with benign teratomas. [39]  

Tumor markers, such as squamous cell carcinoma (SCC) antigen, are useful for identifying the presence of SCC arising from mature cystic teratoma (MCT), but no set cut-off level has been established. Choi et al reported elevated SCC antigen levels ranging from 1.5 ng/mL in International Federation of Gynecology and Obstetrics (FIGO) stage Ia tumors to 11.3 ng/mL in stage IIIc in four patients with confirmed SCC arising from MCT. [42]  

 

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Imaging Studies

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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Procedures

Fine-needle aspiration or core biopsy can be used to differentiate benign from malignant mediastinal masses in 90% of cases. [41]

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Histologic Findings

In cystic teratomas, the outside of the tumor wall is usually lined with native tissue. The cavity of the cyst is often lined with keratinized squamous epithelium and usually contains abundant sebaceous and sweat glands. Hair and other dermal appendages are usually present. Occasionally, the cyst wall is lined with bronchial or gastrointestinal epithelium. Foreign body giant cell reactions may be seen in various parts of the tumor and may, in the case of intraperitoneal teratomas, lead to formation of extensive adhesions if the tumor contents are spilled.

Ectodermal tissue encountered may include brain, glia, neural tissue, retina, choroids, and ganglia. Mesodermal tissue is represented by bone, cartilage, smooth muscle, and fibrous tissue. [48, 50] One report describes a 7-cm ovarian teratoma containing a mandiblelike structure with 8 well-formed teeth. [51]

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Staging

Sacrococcygeal teratomas are the only teratomas with a widely accepted staging or classification system. In a study of 405 patients treated by members of the Surgical Section of the American Academy of Pediatrics, Altman and associates report the following system: [25]

  • Type I tumors are predominantly external, attached to the coccyx, and may have a small presacral component (45.8%). No metastases were associated with this group.

  • Type II tumors have both an external mass and significant presacral pelvic extension (34%) and have a 6% metastasis rate.

  • Type III tumors are visible externally, but the predominant mass is pelvic and intra-abdominal (8.6%). A 20% rate of metastasis was found in this group.

  • Type IV lesions are not visible externally but are entirely presacral (9.6%) and have an 8% metastasis rate.

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