INTRODUCTION: -

Cystic hygroma represent the most common cause for a neck mass detected prenatally. Cystic hygroma are anomalies of the lymphatic system characterized by single or multiple cysts within the soft tissue, usually involving the neck. The incidence varies with gestational age. Reports range from 1.7:10,000 pregnancies to 0.83% of pregnancies at risk for having a structural anomaly. Radenbacher first described cystic hygroma in 1828. The term means a moist tumor. Cystic hygroma belongs to a group of diseases now recognized as lymphatic malformations. The discovery of cystic hygroma has a variable effect and prognosis depending on whether it is found in the antenatal period of the post natal period. This article is focused on the discussion of fetal cystic hygromas, that is, cystic hygromas discovered antenatally.
 
MATERIALS AND METHODS:-

Nine cases of cystic hygroma were diagnosed from January 2006 to November 2007 in Divakar’s Speciality Hospital Bangalore, using ultrasound examination. Routine ultrasond examination was performed on all women with a gestational age of 10 and 14 weeks. Of the 1819 patients who underwent the examination, nine were found to have a fetus with cystic hygroma.
Following the ultrasonic diagnosis of cystic hygroma, the findings were discussed with the couple, and they were counselled regarding the need for karyotyping and for termination of pregnancy

CASES OF CYSTIC HYGROMA:-

CASE I

Fetal Supra-Renal Mass—Diagnosis and Implications

Mrs. X, 29yrs old, third Gravida with an uneventful antenatal period was referred for a mid pregnancy ultrasound. Biometry, structural survey,liqour and placental position were reported normal.

Repeat ultrasound at 38 ½ weeks for assessment of fetal weight & amniotic fluid index detected .
a well defined Ovoid, solid and cystic space occupying lesion measuring 68mm x 48mm x 52 mm in the fetal left renal region. Fetal kidneys, bladder and liquor were normal & there were no other anomalies.

Additional Information:
Neuroblastoma: (2)

Synonyms: Ganglioneuroblastoma, neuroblastoma in situ. BDE: Cancer, neuroblastoma.

Definition: Malignant neoplasm of poorly differentiated nerve cells of embryonic type.

Prevalance: 0.3-1:10,000. M1: F1(6)

Neuroblastoma is the most common malignant tumor in infancy and early childhood, originating anywhere along the sympathetic nervous system, and in the adrenal gland. More than half of neuroblastomas are in the abdomen, and two- thirds of these originate in an adrenal gland. Fifteen percent of neuroblastomas are thoracic, arising posteriorly along the sympathetic chain. Other sites include the cervical region, Sympathetic chain in the abdomen, nasopharynx and brain.

More than half of patients are less than two years of age at diagnosis. Seventy – five percent of tumors are discovered prior to four years of age. The prognosis ranges from over 90% survival if discovered in patients under one year of age, to less than 10% survival when discovered in older children. Accurately early diagnosis is crucial, as the best prognosis is in the youngest patients.

Pathogenesis: Defect in neuroblast maturation with embryonal sympathetic ganglion cells undergo malignant transformation. Associated with n-mycogene and tumor cell ploidy: if n-mycogene is positive and cells are diploid, then the prognosis is worse.
Diagnosis: Ultrasound establishes the diagnosis. Doppler flow studies are useful in assessing the origin of the feeding vessel. MRI could be complimentary in a few cases. Raised biochemical markers in the fetal blood such as the catecholamines and neuron specific enolase is demonstrated . References for neuron specific enolase are available in cord blood (median concentration-8.0micrograms/l). Elevated amniotic fluid catecholamines can be present. Occasionally the mother may exhibit signs due to the increased catecholamine. (2)

Metastatic sites: Frequent: Bone lymph nodes, bone marrow,liver, skin;
occasional: extradural extension into spinal canal, rare: lung.

Associated anomalies: Hydrops, neurofibromatosis, Hirschprung”s disease, some chromosomal abnormalities. May be part of the fetal hydantoin and fetal alcohol syndromes. (6)

Differential diagnosis: Adrenal site: renal duplex anomaly or tumor, adrenal cyst or hemorrhage is less likely.

Extra-adrenal site: Solid mass of lung,

Teratoma:

Germ cell tumor – drives from isolation of one or more blastomeres, fertilization of a polar body or parthogenetic development of egg. Primordial germ cells originate in the yolk sac endoderm and migrate around the hindgut to the genital ridge on the posterior abdominal wall. Aberrant migration accounts for the occurrence of germ cell tumors in midline sites.(7)

The most extreme form is Fetus in fetu –wherein a vertebrate fetus is included within the abdomen of its partner. Masses containing bones, cartilage, teeth, central nervous system tissue, fat and muscle may be found in the abdomen of newborns and children termed `Teratomas'. They are defined as fetus in fetu if there is a recognized trunk and limbs, seemingly an abortive twinning. Although rare they should be removed because of potential effect on normal renal function and slight malignant potential.(8)

Teratoma have tissues from each of 3 layers of Embryonic disc with the ectodermal components, such as the brain tissue ,mesodermal derivatives such as the fat , cartilage, bone and muscle. Teratomas may be classified as mature or immature on the basis of the presence of immature neuroectodermal elements within the tumor.

The most common is Sacrococcygeal teratoma – 1: 35-40,000 is 4 times as frequent in female than in male fetus. When the tumors are resected before the patient is aged 2 months, 7-10% are malignant. After that age, the risk of malignancy increases greatly to more than 50%.
The physiologic consequence of fetal SCT depends on the blood flow to the tumor, the metabolic demands of the tumor and the severity of anemia. Large Sacro coccygeal teratomas may parasitize blood supply from the middle sacral artery or the internal and external iliac systems. This causes vascular steal from the umbilical-artery blood flow to the placenta resulting in fetal anemia and high-output cardiac failure. The effect of the teratoma on the fetal circulation can be documented by Doppler flow study and echocardiography.
Non immune hydrops fetalis is secondary to high output failure in fetuses with teratomas. (9,10)

Recently, targeted ablation of the feeding tumor vessels to interrupt blood flow to fetal SCT has been successfully accomplished by in utero radiofrequency ablation. In this regard, 3D ultrasound is very useful in the investigation of fetal Sacro coccygeal teratoma for which detailed assessments of the structural defects of the fetus and the vasculature of the tumor are required. (10)

According to the present state of the art, diagnosis of a sacrococcygeal teratoma only leads to specific monitoring of the pregnancy , because an early delivery or delivery by cesarean section will be necessary in some cases to improve the prognosis of child and mother.For other types of tumors investigations and actions should be delayed until after birth.

Surgical resection is the treatment of choice for teratomas.In case of sacrococcygeal teratoma, the entire coccyx needs to be removed along with the tumour.

Childrens Oncology Group staging for extragonadal germ cell tumors(7)

• Stage I - Complete resection at any site, en bloc coccygectomy for sacrococcygeal site, normal tumor margins, tumor marker levels normal or elevated
• Stage II - Microscopic residual disease, lymph nodes normal, tumor marker levels normal or elevated
• Stage III - Gross residual disease or biopsy only, retroperitoneal nodes normal or involved with metastatic disease, tumor marker levels normal or elevated
• Stage IV - Distant metastases, including those to the liver

The experience with immature teratomas strongly supports using complete resection only, followed by close observation of serum tumor markers and diagnostic imaging.
Those patients unable to undergo complete resection should be offered chemotherapy:

• 4 cycles.
• Cisplatin 20 mg/m2 x 5 days combined with etoposide 100 mg/m2 and bleomycin 15 IU/m2.
• Another 2 cycles of the same chemotherapy for persistent high tumor marker and/or residual tumor by diagnostic imaging.(7)
  

Follow up of these patients should be as follows:

Low-risk Group:

• Even with normalization of AFP, patients with stage I disease must be observed cautiously, because 20% to 40% of false-negative measurements have been identified and retroperitoneal nodal disease has occurred before elevation of AFP.
• Follow-up recommendations:
  
  • Monthly follow-up of markers for two years is mandatory.
  • Patients with no or unknown markers at diagnosis, P.E. and abdominal ultrasound should be done every 2 months for 2 years.

High-risk group(7)

• A large proportion of these patients are likely to have initial biopsy followed by a definitive surgical excision after maximal chemotherapy effect.
• 4 courses of standard PEB.
• Definite surgical procedure after receiving induction chemotherapy – complete vs. partial resection.
• Pathological evaluation of the resected mass – fibrotic or necrotic tumor (pathologic CR) vs. viable malignant tumor.
• Tumor markers (post chemotherapy and surgery) – normal vs. elevated.

• Giulian BB, chang CCN, Yoss BS; Prenatal ultrasonographic diagnosis of fetal adrenal neuroblastoma. JCU 14:225-227,1986.
• Angela Regina Capelanes, Gloria Valero, Philippe Jeanty.Neuroblastoma.
  Neuroblastoma@Capelanes/www.thefetus.net
• Humberto L Lugo-Vicente.Pediatric surgery hand book. University of Puerto Rico school of Medicine.
• Sbragia L, Paek BW, Feldstein VA, Farell JA, Harrison MR, Albanese CT, Farmer DL. Outcome of prenatally diagnosed solid fetal tumors. J.Pediatr Surg 2001;89360:1244-7.
• Frederic Gauthier, Olivier de Drenzy and Jacques Valayer. Prenatal ultrasonographic detection of abdominal and pelvic tumors: impact on management. Pediatric surgery international volume11, Number 1, Jan 1996page8-3.
• Judy A. Estroff:MD, Robert C. Shamberger,MD,Lisa Diller,MD,Beryl R.Benacerraf 1991-12-07-17. Neuroblastoma @Estroff www.thefetus.net
• Estanton Adkins III, Rebeccah Brown, Mary L Windle et al.Teratomas and other Germ cell tumors, June 20,2003,emedicine from webMD.
• SV Phatak , PK Kolwadkar, MS phatak, Fetus in Fetii: a case report. Ind J Radiol imag 2003 13:1:93-94.
• Soo-Hyun lee, Jeong Yeon cho, Mi Jinsong et al, Prenatal ultrasound findingsof fetal neoplasms.Korean Journal of Radiology,2002 March;3(1):64-73.
• C.P.chen, J.C.Shih, Prenatal visualization of the vasculature of fetal sacrococcygeal teratoma by three dimensional color power angiography. Ultrasound in obstetrics and Gynaecology. Vol 20,page636,December 2002.