SCT

Question 1

What is the embryologic origin of EG teratoma

Answer 1

totipotent (primordial) endodermic germs cells of the yolk sac miss their target during migration.

2 other theories

• residual totipotent germ cells along primitive streak (explaining predisposition for midline tumors)
• incomplete twinning (part of spectrum from fetus in fetu to normal twin) controversial

Question 2

How is a teratoma defined histologically.

Answer 2

evidence of histological element of all 3 germ cell layers (ecto/endo/meso).

recent classification recognizes that immature teratomas can demonstrate monodermal subtypes.

Question 3

What are the different germ cell tumors

Answer 3

Teratoma
germinomas (formely known as dysgerminomas)
embryonal carcinoma
yolk sac tumors
choriocarcinomas
gonadoblastomas
mixed germ cell tumors

Gonadal and extragonadal GCT have different tissu origin, explaining different behavior.

Question 4

Describe histologic differences between mature, immature, and malignant teratoma

Answer 4

Mature:
mature tissue

Immature: identification of immature neuroepithelial elements

Malignant: most common malignant component in teratoma is a yolk sac tumor (endodermal sinus tumor)

Although immature elements are not indicative of malignancy, their presence portends an increase risk or recurrence and poorer outcome.

Question 5

Is malignant teratoma frequent at birth?

Answer 5

No. rate increases with age and incomplete resection.

Also, if tumor not identified at birth (eg Altman IV)

Question 6

What tumor markers should be ordered for EG GCT?

Answer 6

AFT: secreted by yolk sac tumors
and some embryonal carcinomas

Bhcg: choriocarcinoma and rarely carcinoem

Question 7

Is a high AFP level at birth indicative of malignancy?

Answer 7

No. AFP is synthesized by the yolk sac and is expected to be high in the new born.

1/2 life is 6 days. levels are expected to normalized by 1 year of age.

Q 3 months AFP should be followed. abscence of normalization or re-elevation after normalization may sign of residual disease or recurrence.

Question 8

Describe the Curarrino triad.

Answer 8

1) sacral anomaly (most often simitar defect)
2) retrorectal mass (often teratoma)
3) Anorectal malformation (often anal stenosis)

Associated with MNX 1 gene defect

In F, association with gynecologic malformation. perform screening pelvic US.

7% association with Hip dislocation in patient with SCT

Question 9

What is the F: M ratio of SCT

Answer 9

3:1

Familial predisposition exists for SCT in general.

Question 10

What are the most common sites for teratoma

Answer 10

1) SCT (45!!)
2) gonadal (30%)
3) mediastinal (6%)

Question 11

what is the incidence of SCT?

Answer 11

1: 40 000 live birth
3F: 1M

Question 12

How is a hamartoma characterized histologically?

Answer 12

mature cells of tissue normally found at that site, but which are growing in a disorganized manner (ex hemangioma)

Question 13

Differential diagnosis for SCT at birth

Answer 13

1: meningocele / myelomeningocele (feel fontanelle)

other are more readily diagnosed: rectal duplication, hamartoma, tail remnant, lymphangiomas, lipomas.

Question 14

Risk of malignancy for an SCT?

Answer 14

at birth: 10%

at 1 year: 40-75%

Question 15

Clinical presentation of SCT complications at birth?

Answer 15

• Hemorrhage
• high-output cardiac failure
• hyperkalemia due to tumor necrosis
• disseminated intravascular coagulopathy
• complication of prematurity

Question 16

On prenatal US suggestive of an SCT, what are the important feature necessary to guide management?

Answer 16

Information to indicate
- ddx (splinal involvement)
impending complications
-admissibility to fetal therapy
-dictate surveillance frequency
-mode of delivery

1) Size (>5m or larger than bi-parietal lenght = c-section)
2) cystic vs solid vs mixed (cystic can be aspirated before vaginal delivery)
3) communication with CNS
4) placentomegaly / hydrops (impending signs of fetal demise, due to high cardica output)
5) polyhydramios (with subsequent placental irritability, may be punctioned)
6) TFR - tumor volume to fetal weight ratio, < 0.12 associated to good prognosis
7) tumor growth < 150 cc / week is associated with a good prognosis

Question 17

Maternal complication of SCT

Answer 17

mirror syndrome

-fetal hydrops associated with maternal preeclampsia

Question 18

What are potential fetal intervention for SCT?

Answer 18

Solid / mixed tumors

• surgical tumor debulking
• US guided RFA/ Alcool injection

Cystic

• punction
• shunt

Timing highly debated. better to deliver prematurely (27 weeks?) or offer in utero intervention?

APSA: <28 weeks, fetal intervention
28-36:EXIT if fetal hemorrhage, high output cardiac failure, impending labor

Question 19

Surgical principle of SCT resection:

Answer 19

• Cross match with blood available
• Prep from nipple to toes
• Most tumors can be approached via prone position
• if concern for bleeding, options include: IR embolization -medial sacral artery, laparoscopic ligation of a., or aortic vascular control
• Multiple possible incisions: sagital, M, inverted V (chevron)
• remove coccyx
• May put gaze/hegar in rectum to ease identification of plane
• fix levator ani to sacrum
• Flip to supine if necessary

Question 20

What is the f/u for SCT patient

Answer 20

q 3 months AFP + PE with DRE x 3 years, than space our

Question 21

What is the chemotherapy regimen for malignant SCT?

Answer 21

Yolk sac tumor demonstrate an excellent response to platinum based regimen.

Patient with an R0 resection of malignant SCT are not given adjuvant chemo upfront (if localized disease) as salvage is excellent with recurrent tumor.

Overall survival > 90%

Question 22

Surgical approach of SCT?

Answer 22

altman type 1-2: prone

3: supine + prone
4: supine

Question 23

Approach for metastatic SCT?

Answer 23

often in older children with type 4.

bx, neoadj, surgery.