Fetal tumors

Question 1

What is a sacrococcygeal teratoma?

Answer 1

A neoplasm composed of tissues from either all three germ layers or multiple foreign tissues lacking an organ specificity arising in the sacrococcygeal region. Though to arise from a totipotent somatic cell originating in Hensen’s node (enlarged group of cells located in the anterior portion of the primitive streak in a developing gastrula)

Question 2

Type I SCT

Answer 2

Completely external, no presacral component

Question 3

Type II SCT

Answer 3

External component and internal pelvic component

Question 4

Type III SCT

Answer 4

External component and internal pelvic component extending into abdomen

Question 5

Type IV SCT

Answer 5

Completely internal and no external component

Question 6

Incidence & epidemiology of SCT

Answer 6

One of the most common tumors in newbornsStill rare - 1 in 30,000 livebirths

Question 7

SCT - more common in males or females?

Answer 7

Females 4x as likely to be affected as males

Question 8

Malignant transformation of SCT - more common in males or females?

Answer 8

Males

Question 9

Characteristics of SCT

Answer 9

Most are solid or mixed solid & cystic. Purely cystic has also been described. Calcifications can be seen microscopically, but usu not visible by prenatal USMost are extremely vascular

Question 10

Other US findings associated with SCT

Answer 10

Polyhydramnios - renal hyperfiltration due to high-output stateHepatomegalyPlacentomegalyNonimmune hydropsHigh-output failure may be due to tumor hemorrhage, severe anemia, or AV shunting within the tumor

Question 11

Anomalies associated with SCT

Answer 11

Incidence of coexisting anomalies is 11-38%CNSGIGUMusculoskeletal

Question 12

Is karyotype recommended for SCT?

Answer 12

Not unless there are multiple anomalies, AMA, or fetal surgery contemplated

Question 13

Use of MRI for SCT?

Answer 13

May be useful in defining the pelvic component of SCT and impact on other pelvic structures, exclude MMC, can aid in operative planning

Question 14

DDx of SCT

Answer 14

Lumbosacral MMCNeuroblastomaGliomaHemangiomaNeurofibromaCordomaLeiomyomaLipomaMelanoma50 other tumors in the sacrococcygeal region

Question 15

Mortality rate for fetal vs neonatally dx’d SCT

Answer 15

50% fetal, 5% neonatal

Question 16

Incidence of malignant elements in fetal SCT

Answer 16

Ranges from 7-30%, more common in males and in solid tumors

Question 17

Antenatal history of SCT

Answer 17

27 cases - 5 TOP, 15 IUFD or NND (hydrops or poly in 7/7 IUFDs)15 cases - 6 survivorsHydrops in SCT is usually, but not always, fatal

Question 18

Blood supply to SCTs

Answer 18

Classically thought to be middle sacral arteryMay “parasitize” blood supply from internal and external iliacs, resulting in vascular steal from UA placental blood flow, may lead to AEDF or REDF

Question 19

Primary cause of death in fetal vs neonatal SCT

Answer 19

Fetal - tumor hemorrhage at deliveryNeonatal - prematurity, malignant invasion

Question 20

Management of pregnancy in SCT

Answer 20

Weekly US for AFI, tumor growth, fetal well-being, hydropsSerial Doppler echo for signs of high-output state (incr diameter of IVC (> 1cm), incr descending aortic flow velocity (>120 cm/s), incr CO (>500 mL/kg/min)Delivery once FLM after 36wSVD if small tumor

Question 21

Complications of vaginal delivery in SCT

Answer 21

Fetal death after rupture, avulsion, or asphyxiaCD recommended to avoid trauma-induced hemorrhage or dystocia, especially in large (>5-10 cm) tumors. A large tumor may warrant a classical uterine incision, esp in a preterm infant

Question 22

When should fetal intervention be considered for SCT?

Answer 22

In utero resection for large SCT, early signs of hydrops or placentomegaly

Question 23

Treatment of the newborn with SCT

Answer 23

Neonatologist to provide resp supportCareful handling to prevent exsanguinating hemorrhageExcellent venous access, UA and UV cathetersPressors to support hyperdynamic stateTransfusion may be necessaryUrgent resection if hyperdynamic stateSerum AFPs as a marker for recurrence post resection

Question 24

Long-term outcome in SCT

Answer 24

Limited dataIf benign, usually no serious bowel or bladder dysfunction after surgery, most neonates do well following resectionNeurogenic bladder not uncommon if large pelvic componentSubtle gait abnormalities

Question 25

Recurrence risk in SCT

Answer 25

Some cases appear famillial, with AD inheritanceFamilial SCTs are more often Type IV and can be missed, also assoc with anorectal malformations (anal stenosis)Rare cases of chrom abnl including distal 10q trisomy syndrome, mosaic trisomy of 1q, and de novo translocation btw 2 and 7

Question 26

What is Currarino’s triad?

Answer 26

Familial cases of SCT can present as part of this triad - presacral tumor, anorectal malformations, and sacral anomaly