OVARIAN TERATOMASUma Chidiebere John

CONTENTSIntroductionTypesManifestationsCauseDiagnosisRetroconversionComplicationsTreatment

WHAT IS A TERATOMA?Terato - Greek : monster, oma : swelling)Teratomas - embryonic neoplasm from totipotent stem cells.

Component derived from all 3 germ layers.Tissues foreign to the location found.

WHAT CAUSES TERATOMAS?

TYPESMature,

1.cystic2.solidmalignant transformation in < 2%

ImmatureMonodermal, highly specialized

MATURE CYSTIC TERATOMAS

(DERMOID CYSTS)Most common germ cell neoplasmWell-differentiated derivations from at least two of the three germ cell layers

Younger age group (mean patient age, 30 years)

Asymptomatic Grow slowlyBilateral in about 10% of cases

GROSS APPEARANCEUnilocular in 88% of casesFilled with sebaceous material, Squamous epithelium lines the wall of the cyst, Hyalinized ovarian stroma covers the external surface

Hair follicles, skin glands, muscle, and other tissues lie within the wall.

Gross appearance of a mature dermoid cyst

COMMON TISSUES IN A DERMOID CYSTMesodermal tissue (fat, bone, cartilage, muscle) – 90%

Endodermal tissue (gastrointestinal and bronchial epithelium, thyroid tissue) – 80%

Adipose tissue 67-75%Teeth – 31%

MANIFESTATIONS FOR DIAGNOSISRokitansky noduleEchogenic area usually demonstrating sound attenuation owing to sebaceous material and hair within the cyst cavity

Multiple thin, echogenic bands caused by hair in the cyst cavity

ROKITANSKY NODULEA raised protuberance projecting into the cyst cavity. Most of the hair typically arises from this protuberance. When bone or teeth are present, they tend to be located within this nodule

MATURE, SOLIDHas no identifiable immature components Are benign, corresponding to grade 0 immature teratomas.

Radiologically indistinguishable from immature teratomas and occur in a similar age group (20 years).

Fat may be visible at MR imaging or CT

Mature solid teratoma

IMMATURE TERATOMASDemonstrate clinically malignant behaviorMuch less common (1% of ovarian teratomas)Affect a younger age group (mean patient age, 20 years)

Histologically distinguished by the presence of immature or embryonic tissues

Usually perforated

Photograph of an immature teratoma

At initial manifestation, immature teratomas are typically larger (14–25 cm) than mature cystic teratomas (average, 7 cm)

May be solid or have a prominent solid component with cystic elements.

Usually filled with serous or mucinous fluid or may be filled with fatty sebaceous material.

RELATIONSHIP BETWEEN MATURE AND IMMATUREIpsilateral typical mature cystic teratomas are present in 26% of cases of immature teratoma, and an immature teratoma will be seen in the contralateral ovary in 10%

GROSS APPEARANCETumors are heterogeneous, partially solid lesionsScattered calcificationsSmall foci of fatAt CT and MR imaging, irregular solid component containing coarse calcifications and small foci of fat is seen.

Hemorrhage is often present.

Gross appearance of immature teratoma

RETROCONVERSIONThis is a situation where immature teratomas undergo tissue maturation and take on an appearance more typical of mature cystic teratomas.

CT features of maturation includei. increased density of mass lesions, ii. the onset of internal calcification, with fatty

areas and cystic change.

MONODERMAL TERATOMAS Composed predominantly or solely of one tissue type.

There are three main types of ovarian monodermal tumors: i. struma ovarii, ii. ovarian carcinoid tumors, and iii. tumors with neural differentiation.

STRUMA OVARIIComposed predominantly or solely of mature thyroid tissue

Such thyroid tissue can occur as a minor component of mature cystic teratomas.

Accounts for approximately 3% of all mature teratomas.

In rare cases, thyrotoxicosis has been seen as a complication of struma ovarii

GROSS APPEARANCEConsists of amber-colored thyroid tissue, hemorrhage, necrosis, and fibrosis.

Malignancy is uncommonThe US features:

a heterogeneous, predominantly solid masswith multiple cystic and solid areas

MR imaging findings: The cystic spaces demonstrate both high and low signal intensity on T1- and T2-weighted images

No fat is evident in these lesions.

CARCINOID TUMORS Uncommon. May be insular (islet tumors), trabecular, or mucinous.

Frequently associated with a mature cystic teratoma or mucinous tumor

At gross pathologic examination, ovarian carcinoid tumors are solid

Usually occur in postmenopausal women. Most of these tumors have a relatively benign clinical course, with metastases being uncommon.

Secretory granules are seen within the tumor cells,

Immunocytochemical analysis demonstrates serotonin and hormonal peptides.

Carcinoid syndrome is uncommon.

NEURAL TUMORS Monodermal teratomas with neuroectodermal differentiation can form benign, or primitive neuroectodermal tumors

May be associated with glia formation.

SYMPTOMS OF TERATOMAAbdominal pain; depending on the sizeDyspareuniaCompression

LAB WORKUPSerum alpha-fetoprotein (AFP) Beta-human chorionic gonadotropin (HCG)Cancer antigen 125 (CA125), CA19-9, and Carcinoembryonic antigen (CEA)

DIAGNOSISUS

Rokitansky noduleEchogenic area

CTFat attenuation, with/without calcification in the wall

MRISebaceous component has a very high signal for T1Fat attenuation, T2

Ultrasound image of a mature dermoid cyst

Axial unenhanced CT scan shows intratumoral fat (small arrows) and calcifications (large arrow)

COMPLICATIONSOvarian torsion: ~3-16% of ovarian teratomas,Rupture: ~1-4%; peritonitisMalignant transformation: ~1-2%, usually into squamous cell carcinoma (adults) or rarely into endodermal sinus tumors (pediatrics)

Superimposed infection: 1%

Axial contrast-enhanced CT scans show several free-floating areas of fat attenuation from a perforated dermoid cyst

Photograph of squamous cell carcinoma malignanttransformation within a mature cystic teratoma

STAGINGStage 1 - means the cancer is only in the ovary (or both ovaries)

Stage 2 - means the cancer has spread into the fallopian tube, womb, or elsewhere in the area circled by your hip bones (your pelvis)

Stage 3 - means the cancer has spread to the lymph nodes or to the tissues lining the abdomen (called the peritoneum)

Stage 4 - means the cancer has spread to another body organ some distance away, for example the lungs

3D-reconstructed CT showing a calcification

DDXBlood clotHemorrhagic cystEchogenic bowelPerforated appendix with appendicolithPedunculated lipoleiomyoma of the uterusOvarian serous or mucinous cystadenoma/cystadenocarcinoma 

TREATMENTGoals

Removal, where possibleRelief of symptoms

Depends on diagnosisSurgical excision.Chemotherapy

Follow-up

RECURRENCERisk of recurrence related to degree of maturity.<10% in completely resected mature Teratoma.33% immature Teratoma.

Completeness of resection.

REFERENCES Williams GYNECOLOGY Radiographics (RSNA) Medscape Cancer Research UK Patient Info University of Ottawa Radiopaedia