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Prenatal sonographic features of sacrococcygeal teratoma
International Journal of Gynecology & Obstetrics 67 Ž1999. 95]101
Case report
Prenatal sonographic features of sacrococcygeal teratoma T. Tongsong a,U , C. Wanapirak a , W. Piyamongkola , J. Sudasanab b
a Department of Obstetrics and Gynecology, Chiang Mai Uni¨ ersity, Chiang Mai, Thailand Department of Pediatrics, Faculty of Medicine, Chiang Mai Uni¨ ersity, Chiang Mai, Thailand
Received 16 April 1999; received in revised form 30 July 1999; accepted 4 August 1999
Abstract Objecti¨ e: To describe the potential role of ultrasound in prenatal diagnosis of fetal sacrococcygeal teratoma ŽSCT.. Subjects: A total of four fetuses with prenatal diagnosis of SCT were sonographically evaluated and followed-up. Results: Fetal SCT was diagnosed at 13, 17, 26 and 27 weeks of gestation. Three of them had predominantly solid tumors with scattered cystic areas, whereas the other one had an entirely cystic tumor. One had a rapid growth tumor and finally developed early hydrops. Three had polyhydramnios and delivered prematurely. The diagnosis was posnatally confirmed in all cases. In the case with the large tumor, a cesarean section was done to avoid traumatic delivery. Two cases survived and the tumors were successfully resected, whereas the others died due to heart failure secondary to hydrops in one case and prematurity in the other one. Conclusion: This small series suggests that SCT be readily diagnosed in utero, possibly as early as first trimester. The important clue was an abnormal mass in the sacrococcygeal area. The prenatal diagnosis can contribute to changes in clinical decision. Q 1999 International Federation of Gynecology and Obstetrics. Keywords: Prenatal diagnosis; Sacrococcygeal teratoma; Ultrasound
U
Corresponding author.
0020-7292r99r$20.00 Q 1999 International Federation of Gynecology and Obstetrics. PII: S 0 0 2 0 - 7 2 9 2 Ž 9 9 . 0 0 1 1 8 - 6
T. Tongsong et al. r International Journal of Gynecology & Obstetrics 67 (1999) 95]101
96
1. Introduction
2. Materials and methods
A teratoma is generally defined as a tumor arising from pluripotent cells, composed of a wide variety of tissues haphazardly arranged, usually representing derivatives of their germ layers w1x. Sacrococcygeal teratoma ŽSCT. is usually obvious at birth, presenting as a large midaxial exophytic mass in the sacrococcygeal region. SCT may be nearly entirely external Žtype I., combined internal and external equally Žtype II., mainly internal Žtype III., or entirely internal Žtype IV.. Like all teratomas, it may be cystic or solid. Unlike most human neoplasms, they are classified into benign, malignant and immature, the majority are benign. SCT is a rare tumor, but the most common fetal tumor, with an incidence of 1:20 000]1:40 000 live births w2x. The male-to-female ratio is 1:3. Most cases are sporadic, but familial presacral teratomas have been reported w2x. Since the advent of ultrasonography, diagnosis has more commonly been made prenatally. With modern imaging techniques, complications such as severe dystocia caused by the tumor, fetal hydrops, polyhydramnios, or bleeding of the tumor from tears during parturition can be preventable. Therefore, prenatal diagnosis is of clinical importance for proper management. The prenatal diagnosis of SCT has been reported but only in a limited number w3]10x. The objective of this study is to demonstrate the potential role of ultrasound in diagnosis and management of SCT.
Ultrasound examinations were performed by the authors from June 1989 to December 1998, using a convex transabdominal transducer of 3.5 MHz and a transvaginal transducer of 5 MHz ŽAloka SSD 650, 680EX, and SSD 1700, Tokyo, Japan.. Ultrasound examination was performed with general obstetric indications, not routinely. The important sonographic feature for diagnosis was abnormal mass arising at the sacrococcygeal area. The other associated anomalies were also carefully identified and documented. When sacrococcygeal teratoma was diagnosed, previous obstetric history was carefully reviewed and the proper counseling was given. The patients were followed-up until discharge from the hospital.
3. Results During the study period, four fetuses with sacrococcygeal teratoma were found in 59 879 births, a prevalence of 1:15 000 births Žin the tertiary center.. All of them were prenatally diagnosed with ultrasound, which was performed due to obstetric indications. None had familial history of this disorder. The demographic information and sonographic findings of the fetuses are represented in Tables 1 and 2, respectively. Figs. 1]4 show prenatal sonographic findings and postnatal appearance of cases
Table 1 Summarized demographic data of the patients No.
Ages
Parity
Weeks of diagnosis
Indications for ultrasound exams
Weeks of delivery
Newborns
1
25
0]0]1]0
27
35
2
37
2]0]0]2
17
3
20
0]0]0]0
13
4
28
1]0]0]1
26
Large-for-date uterine size Amniocentesis for karyotype Large-for-date uterine size Premature labor and large-for-date uterine size
Female, 3610 g stillborn Female, 3200 g survived Female, 2450 g survived Female, 1700 g neonatal death
40 36 30
T. Tongsong et al. r International Journal of Gynecology & Obstetrics 67 (1999) 95]101
97
Table 2 Sonographic findings of the fetuses Case no.
Weeks of diagnosis
Type of tumor
Sonographic findings
1
27
II
Solid echogenic mass with small area of cystic component, anterior to sacrum and coccyx, located partly in the pelvis and partly outside, size of 6 = 5 = 4 cm in diameter, polyhydramnios. The mass becoming more complex and lobulated with larger area of small sonolucent area and most part growing beyond the pelvis, the diameter approximately 10 cm, high vascularization slightly cardiomegaly, polyhydramnios. The mass becoming bigger, mainly external ) 15 cm in diameter, early hydrops fetalis with ascites and cardiomegaly but no placentomegaly no subcutaneous edema, polyhydramnios.
17
IV
Cystic mass with diameter of 3 = 2.5 = 2 cm Located at anterior surface of sacrum and coccyx, completely internal, normal amniotic fluid volume.
25,29,33 37
III II
The same appearance but much bigger, Ž12 cm in diameter at 37 weeks., growing caudally outside, and finally predominantly external, normal amniotic fluid volume.
13
II
Solid mass with mixed echo caudal to sacrum and coccyx with diameter of 2.5= 2.5= 2 cm Subjectively increased amniotic fluid. Slow increase in size, excessive skin flap over the mass, polyhydramnios
II
Solid mass with mixed echo caudal to sacrum and coccyx with diameter of 7 cm, polyhydramnios partly internal and partly external.
31
35
2
3
21,29,33
4
26
1]4, respectively. The diagnosis of all cases was confirmed by postnatal pathology. The mean maternal age was 27.5 years Žrange 20]37 years.. Gestational age at first diagnosis was varied from as early as 13 to 27 weeks. Large-for-date uterine size was the main indication for ultrasound examination. On ultrasound, none of them were associated with other anomalies, however, Case 1 developed hydrops fetalis secondary to the presence of a large mass with high vascularization. The growth of tumor mass was varied. In Case 1, the rapid growth from 27 to 35 weeks was demonstrated and hydrops fetalis finally developed, whereas the
growth in Case 3 was markedly slow. Only Case 2 was entirely cystic, whereas the remainder had solid tumor with only a small area of cystic component. Polyhydramnios was documented in three of them. Follow-up ultrasound was serially done with intervals of 1]2 weeks in all cases. Generally, repeated ultrasound revealed the same appearance, but increase in size of the tumor with varied growth rate. Notably, three had preterm delivery and all were associated with polyhydramnios. Case 1 was delivered by cesarean section due to large tumor size. The remainders were vaginally delivered. Postnatal examinations and pathological stud-
98 T. Tongsong et al. r International Journal of Gynecology & Obstetrics 67 (1999) 95]101 Fig. 1. Case 1: ŽA. saggital scan of the fetus at 27 weeks showing echogenic mass of SCT; ŽB. the complex mass of SCT at 35 weeks with ascites; ŽC. the postnatal appearance of the SCT at 35 weeks. Fig. 2. Case 2: ŽA. cross-sectional scan of the fetal pelvis at 17 weeks showing cystic mass of SCT; ŽB. saggital scan at 29 weeks; ŽC. the postnatal appearance of the SCT at 40 weeks.
T. Tongsong et al. r International Journal of Gynecology & Obstetrics 67 (1999) 95]101 Fig. 3. Case 3: ŽA. saggital scan of the fetus at 21 weeks showing solid tumor at the caudal end; ŽB. the sonographic appearance at 29 weeks; ŽC. the postnatal appearance of the SCT at 33 weeks. Fig. 4. Case 4: ŽA and B. saggital scan of the fetal rump at 26 weeks; ŽC. postnatal appearance of the SCT at 30 weeks. 99
100
T. Tongsong et al. r International Journal of Gynecology & Obstetrics 67 (1999) 95]101
ies confirmed the prenatal sonographic findings and all tumors were found to be benign. None of them had other associated congenital malformations. Perinatal death occurred in two cases. Case 1 died shortly after birth from heart failure associated with hydrops fetalis. Case 4 developed respiratory distress syndrome and died before surgical correction of the tumor. The other two cases survived and the tumors were successfully resected in the neonatal period.
4. Discussion Our results suggest that the routine ultrasound in early pregnancy allows early diagnosis of a SCT with a high degree of certainty. The majority of these teratoma are solid or mixed cystic and solid external caudal masses. A conclusion drawn from our results and the literature is that only a small percentage are entirely cystic } like Case 2 in this study. Large solid tumors may lead to hydrops fetalis and intrauterine death. Most tumors are benign and resectable and a good outcome can be anticipated, however, perinatal morbidity and mortality are obviously increased due to hydrops fetalis and premature delivery secondary to polyhydramnios. Therefore, prenatal diagnosis with appropriate obstetric and pediatric care is of critical value. A careful sonographic examination allows a good prenatal prognosis as to the severity of the malformation. Prenatal detection and size determination of the external component can play an important role in planning obstetric management because fetuses with large tumors should be delivered by cesarean section to avoid dystocia and catastrophic hemorrhage during delivery w5,10x. Small teratomas, as well as most cystic tumors, allow vaginal delivery after having been punctured previously. Ultrasound allowed visualization of an intra-abdominal component in most cases, and assessment of findings that were of prognostic importance. However, there was no correlation between the sonographic appearance and the presence of immature or malignant components w8x. Furthermore, two-dimensional Doppler echo-
cardiography can be used to diagnose congestive heart failure in early hydrops secondary to a large SCT w9x leading to allow timely therapeutic interventions, though our Case 1 resulted in stillbirth. In addition, currently, open surgery has been prenatally performed on fetuses with SCT associated with hydrops w11x. Based on the series presented here and a review of the literature, SCT can be accurately diagnosed which is related to significant fetal wastage as well as neonatal morbidity and mortality. Prenatal diagnosis is possible as early as the first trimester, e.g. Case 3 in this series and transvaginal ultrasound is probably helpful in this situation. Follow-up ultrasound examination is required, as these masses can grow rapidly and cause congestive heart failure from the vascularity and shunting within the tumor. Each tumor appeared as a large mass arising from the fetal rump. The teratomas exhibited three sonographic patterns: mixtures of cystic and solid components in equal proportions; predominantly solid with a few scattered anechoic areas; and unilocular cystic masses. Although the prenatal diagnosis could be made with confidence in our cases, the major sonographic differential diagnoses should include anterior or posterior meningomyeloceles, conjoined twins especially in large tumor, hemangioma, neuroectodermal cysts w12x. Ultrasound can usually distinguish SCT from neural tube defects. For type IV Žentirely internal ., the differential diagnosis for this unique presentation of SCT is different from that considered for predominantly external complex tumors. Type 1 Žentirely external. cystic sacrococcygeal teratoma, usually associated with a good outcome following neonatal resection, must be differentiated at the time of prenatal diagnosis from sonographically similar to meningomyeloceles, which carry a grave prognosis. Color Doppler imaging may assist correct midtrimester prenatal diagnosis of a large type 1 cystic sacrococcygeal teratoma closely simulating a meningomyelocele w13x. In addition, elevated maternal serum alpha-fetoprotein may be helpful in diagnosis, however alpha-fetoprotein can be normal or elevated in this condition w5x. Unfortunately, alpha-fetoprotein measurement was not studied in any case of our series.
T. Tongsong et al. r International Journal of Gynecology & Obstetrics 67 (1999) 95]101
Serial ultrasound examinations should be performed during pregnancy to assess amniotic fluid volume, tumor growth, fetal well being, and early evidence of hydrops. Evidence of heart failure, placentomegaly, or hydrops fetalis should be sought because these may progress rapidly like in Case 1. Fetal and placental hydrops are common findings with large SCT. Hydrops may be due to either a combination of high cardiac output failure secondary to the increased vascular bed in the tumor or hypoproteinemia secondary to increased protein loss through abnormal tumor capillaries. Fatal outcome when SCT was associated with hydrops almost always occurred. Case 1 was an example in spite of early diagnosis with only evidence of slightly cardiomegaly and ascites without placentomegaly. Like previous reports, most fetuses with SCT do not reach 36 weeks of gestation because premature delivery is a common complication, with uterine distension from tumor bulk or polyhydramnios being the most likely causes. Warning signs and symptoms of preterm labor should be stressed at prenatal visits and limitation of activity and frequent cervical checks may be indicated. During labor, severe dystocia may occur in infants with large tumors if delivered vaginally, with an extremely high fetal morbidity and mortality rate. The large tumor like Case 1 warranted cesarean section to avoid traumatic delivery. In conclusion, we emphasize that with careful assessment of fetal rump and spine completely in screening for anomaly, SCT can readily be diagnosed even in first trimester and the prenatal diagnosis contributes to changes in management. The successful management of SCT could be achieved with accurate prenatal diagnosis, and early surgical intervention. The role of sonography in the management of these cases should be stressed.
101
References w1x Gonzalez-Crussi F, Sotelo-Avila C. Congenital tumors. In: Wigglesworth JS, Singer DB, editors. Textbook of fetal and perinatal pathology. 2nd ed. Malden: Blackwell Science, 1998:412]415. w2x Tapper D, Lack EE. Teratomas in infancy and childhood. Ann Surg 1983;198:398. w3x Burgess I, Hines B, Stevenson P. Cystic type IV sacrococcygeal teratoma detected at 18-week prenatal ultrasound. Ultrasound Obstet Gynecol 1998;11:305. w4x Winderl LM, Silverman RK. Prenatal identification of a completely cystic internal sacrococcygeal teratoma Žtype IV.. Ultrasound Obstet Gynecol 1997;9:425]428. w5x Holzgreve W, Miny P, Anderson R, Golbus MS. Experience with 8 cases of prenatally diagnosed sacrococcygeal teratomas. Fetal Ther 1987;2:88]94. w6x Shipp TD, Shamberger RC, Benacerraf BR. Prenatal diagnosis of a grade IV sacrococcygeal teratoma. J Ultrasound Med 1996;15:175]177. w7x Morrow RJ, Whittle MJ, McNay MB, Cameron AD, Raine PA, Gibson AA. Prenatal diagnosis of an intraabdominal sacrococcygeal teratoma. Prenat Diagn 1990;10:753]756. w8x Sheth S, Nussbaum AR, Sanders RC, Hamper UM, Davidson AJ. Prenatal diagnosis of sacrococcygeal teratoma: sonographic-pathologic correlation. Radiology 1988;169:131]136. w9x Alter DN, Reed KL, Marx GR, Anderson CF, Shenker L. Prenatal diagnosis of congestive heart failure in a fetus with a sacrococcygeal teratoma. Obstet Gynecol 1988;71:978]981. w10x Sepulveda WH. Prenatal sonographic diagnosis of congenital sacrococcygeal teratoma and management. J Perinat Med 1989;17:93]97. w11x Adzick NS, Crombleholme T, Morgan M, Quinn T. A rapidly growing fetal teratoma. Lancet 1997;349:538. w12x Bloechle M, Bollmann R, Wit J, Buttenberg S, Kursawe R, Guski H. Neuroectodermal cyst may be a rare differential diagnosis of fetal sacrococcygeal teratoma: first case report of a prenatally observed neuroectodermal cyst. Ultrasound Obstet Gynecol 1996;7:64]67. w13x Sherer DM, Fromberg RA, Rindfusz DW, Harris BH, Sanz LE. Color Doppler aided prenatal diagnosis of a type 1 cystic sacrococcygeal teratoma simulating a meningomyelocele. Am J Perinatol 1997;34:13]15.
Case report
Prenatal sonographic features of sacrococcygeal teratoma T. Tongsong a,U , C. Wanapirak a , W. Piyamongkola , J. Sudasanab b
a Department of Obstetrics and Gynecology, Chiang Mai Uni¨ ersity, Chiang Mai, Thailand Department of Pediatrics, Faculty of Medicine, Chiang Mai Uni¨ ersity, Chiang Mai, Thailand
Received 16 April 1999; received in revised form 30 July 1999; accepted 4 August 1999
Abstract Objecti¨ e: To describe the potential role of ultrasound in prenatal diagnosis of fetal sacrococcygeal teratoma ŽSCT.. Subjects: A total of four fetuses with prenatal diagnosis of SCT were sonographically evaluated and followed-up. Results: Fetal SCT was diagnosed at 13, 17, 26 and 27 weeks of gestation. Three of them had predominantly solid tumors with scattered cystic areas, whereas the other one had an entirely cystic tumor. One had a rapid growth tumor and finally developed early hydrops. Three had polyhydramnios and delivered prematurely. The diagnosis was posnatally confirmed in all cases. In the case with the large tumor, a cesarean section was done to avoid traumatic delivery. Two cases survived and the tumors were successfully resected, whereas the others died due to heart failure secondary to hydrops in one case and prematurity in the other one. Conclusion: This small series suggests that SCT be readily diagnosed in utero, possibly as early as first trimester. The important clue was an abnormal mass in the sacrococcygeal area. The prenatal diagnosis can contribute to changes in clinical decision. Q 1999 International Federation of Gynecology and Obstetrics. Keywords: Prenatal diagnosis; Sacrococcygeal teratoma; Ultrasound
U
Corresponding author.
0020-7292r99r$20.00 Q 1999 International Federation of Gynecology and Obstetrics. PII: S 0 0 2 0 - 7 2 9 2 Ž 9 9 . 0 0 1 1 8 - 6
T. Tongsong et al. r International Journal of Gynecology & Obstetrics 67 (1999) 95]101
96
1. Introduction
2. Materials and methods
A teratoma is generally defined as a tumor arising from pluripotent cells, composed of a wide variety of tissues haphazardly arranged, usually representing derivatives of their germ layers w1x. Sacrococcygeal teratoma ŽSCT. is usually obvious at birth, presenting as a large midaxial exophytic mass in the sacrococcygeal region. SCT may be nearly entirely external Žtype I., combined internal and external equally Žtype II., mainly internal Žtype III., or entirely internal Žtype IV.. Like all teratomas, it may be cystic or solid. Unlike most human neoplasms, they are classified into benign, malignant and immature, the majority are benign. SCT is a rare tumor, but the most common fetal tumor, with an incidence of 1:20 000]1:40 000 live births w2x. The male-to-female ratio is 1:3. Most cases are sporadic, but familial presacral teratomas have been reported w2x. Since the advent of ultrasonography, diagnosis has more commonly been made prenatally. With modern imaging techniques, complications such as severe dystocia caused by the tumor, fetal hydrops, polyhydramnios, or bleeding of the tumor from tears during parturition can be preventable. Therefore, prenatal diagnosis is of clinical importance for proper management. The prenatal diagnosis of SCT has been reported but only in a limited number w3]10x. The objective of this study is to demonstrate the potential role of ultrasound in diagnosis and management of SCT.
Ultrasound examinations were performed by the authors from June 1989 to December 1998, using a convex transabdominal transducer of 3.5 MHz and a transvaginal transducer of 5 MHz ŽAloka SSD 650, 680EX, and SSD 1700, Tokyo, Japan.. Ultrasound examination was performed with general obstetric indications, not routinely. The important sonographic feature for diagnosis was abnormal mass arising at the sacrococcygeal area. The other associated anomalies were also carefully identified and documented. When sacrococcygeal teratoma was diagnosed, previous obstetric history was carefully reviewed and the proper counseling was given. The patients were followed-up until discharge from the hospital.
3. Results During the study period, four fetuses with sacrococcygeal teratoma were found in 59 879 births, a prevalence of 1:15 000 births Žin the tertiary center.. All of them were prenatally diagnosed with ultrasound, which was performed due to obstetric indications. None had familial history of this disorder. The demographic information and sonographic findings of the fetuses are represented in Tables 1 and 2, respectively. Figs. 1]4 show prenatal sonographic findings and postnatal appearance of cases
Table 1 Summarized demographic data of the patients No.
Ages
Parity
Weeks of diagnosis
Indications for ultrasound exams
Weeks of delivery
Newborns
1
25
0]0]1]0
27
35
2
37
2]0]0]2
17
3
20
0]0]0]0
13
4
28
1]0]0]1
26
Large-for-date uterine size Amniocentesis for karyotype Large-for-date uterine size Premature labor and large-for-date uterine size
Female, 3610 g stillborn Female, 3200 g survived Female, 2450 g survived Female, 1700 g neonatal death
40 36 30
T. Tongsong et al. r International Journal of Gynecology & Obstetrics 67 (1999) 95]101
97
Table 2 Sonographic findings of the fetuses Case no.
Weeks of diagnosis
Type of tumor
Sonographic findings
1
27
II
Solid echogenic mass with small area of cystic component, anterior to sacrum and coccyx, located partly in the pelvis and partly outside, size of 6 = 5 = 4 cm in diameter, polyhydramnios. The mass becoming more complex and lobulated with larger area of small sonolucent area and most part growing beyond the pelvis, the diameter approximately 10 cm, high vascularization slightly cardiomegaly, polyhydramnios. The mass becoming bigger, mainly external ) 15 cm in diameter, early hydrops fetalis with ascites and cardiomegaly but no placentomegaly no subcutaneous edema, polyhydramnios.
17
IV
Cystic mass with diameter of 3 = 2.5 = 2 cm Located at anterior surface of sacrum and coccyx, completely internal, normal amniotic fluid volume.
25,29,33 37
III II
The same appearance but much bigger, Ž12 cm in diameter at 37 weeks., growing caudally outside, and finally predominantly external, normal amniotic fluid volume.
13
II
Solid mass with mixed echo caudal to sacrum and coccyx with diameter of 2.5= 2.5= 2 cm Subjectively increased amniotic fluid. Slow increase in size, excessive skin flap over the mass, polyhydramnios
II
Solid mass with mixed echo caudal to sacrum and coccyx with diameter of 7 cm, polyhydramnios partly internal and partly external.
31
35
2
3
21,29,33
4
26
1]4, respectively. The diagnosis of all cases was confirmed by postnatal pathology. The mean maternal age was 27.5 years Žrange 20]37 years.. Gestational age at first diagnosis was varied from as early as 13 to 27 weeks. Large-for-date uterine size was the main indication for ultrasound examination. On ultrasound, none of them were associated with other anomalies, however, Case 1 developed hydrops fetalis secondary to the presence of a large mass with high vascularization. The growth of tumor mass was varied. In Case 1, the rapid growth from 27 to 35 weeks was demonstrated and hydrops fetalis finally developed, whereas the
growth in Case 3 was markedly slow. Only Case 2 was entirely cystic, whereas the remainder had solid tumor with only a small area of cystic component. Polyhydramnios was documented in three of them. Follow-up ultrasound was serially done with intervals of 1]2 weeks in all cases. Generally, repeated ultrasound revealed the same appearance, but increase in size of the tumor with varied growth rate. Notably, three had preterm delivery and all were associated with polyhydramnios. Case 1 was delivered by cesarean section due to large tumor size. The remainders were vaginally delivered. Postnatal examinations and pathological stud-
98 T. Tongsong et al. r International Journal of Gynecology & Obstetrics 67 (1999) 95]101 Fig. 1. Case 1: ŽA. saggital scan of the fetus at 27 weeks showing echogenic mass of SCT; ŽB. the complex mass of SCT at 35 weeks with ascites; ŽC. the postnatal appearance of the SCT at 35 weeks. Fig. 2. Case 2: ŽA. cross-sectional scan of the fetal pelvis at 17 weeks showing cystic mass of SCT; ŽB. saggital scan at 29 weeks; ŽC. the postnatal appearance of the SCT at 40 weeks.
T. Tongsong et al. r International Journal of Gynecology & Obstetrics 67 (1999) 95]101 Fig. 3. Case 3: ŽA. saggital scan of the fetus at 21 weeks showing solid tumor at the caudal end; ŽB. the sonographic appearance at 29 weeks; ŽC. the postnatal appearance of the SCT at 33 weeks. Fig. 4. Case 4: ŽA and B. saggital scan of the fetal rump at 26 weeks; ŽC. postnatal appearance of the SCT at 30 weeks. 99
100
T. Tongsong et al. r International Journal of Gynecology & Obstetrics 67 (1999) 95]101
ies confirmed the prenatal sonographic findings and all tumors were found to be benign. None of them had other associated congenital malformations. Perinatal death occurred in two cases. Case 1 died shortly after birth from heart failure associated with hydrops fetalis. Case 4 developed respiratory distress syndrome and died before surgical correction of the tumor. The other two cases survived and the tumors were successfully resected in the neonatal period.
4. Discussion Our results suggest that the routine ultrasound in early pregnancy allows early diagnosis of a SCT with a high degree of certainty. The majority of these teratoma are solid or mixed cystic and solid external caudal masses. A conclusion drawn from our results and the literature is that only a small percentage are entirely cystic } like Case 2 in this study. Large solid tumors may lead to hydrops fetalis and intrauterine death. Most tumors are benign and resectable and a good outcome can be anticipated, however, perinatal morbidity and mortality are obviously increased due to hydrops fetalis and premature delivery secondary to polyhydramnios. Therefore, prenatal diagnosis with appropriate obstetric and pediatric care is of critical value. A careful sonographic examination allows a good prenatal prognosis as to the severity of the malformation. Prenatal detection and size determination of the external component can play an important role in planning obstetric management because fetuses with large tumors should be delivered by cesarean section to avoid dystocia and catastrophic hemorrhage during delivery w5,10x. Small teratomas, as well as most cystic tumors, allow vaginal delivery after having been punctured previously. Ultrasound allowed visualization of an intra-abdominal component in most cases, and assessment of findings that were of prognostic importance. However, there was no correlation between the sonographic appearance and the presence of immature or malignant components w8x. Furthermore, two-dimensional Doppler echo-
cardiography can be used to diagnose congestive heart failure in early hydrops secondary to a large SCT w9x leading to allow timely therapeutic interventions, though our Case 1 resulted in stillbirth. In addition, currently, open surgery has been prenatally performed on fetuses with SCT associated with hydrops w11x. Based on the series presented here and a review of the literature, SCT can be accurately diagnosed which is related to significant fetal wastage as well as neonatal morbidity and mortality. Prenatal diagnosis is possible as early as the first trimester, e.g. Case 3 in this series and transvaginal ultrasound is probably helpful in this situation. Follow-up ultrasound examination is required, as these masses can grow rapidly and cause congestive heart failure from the vascularity and shunting within the tumor. Each tumor appeared as a large mass arising from the fetal rump. The teratomas exhibited three sonographic patterns: mixtures of cystic and solid components in equal proportions; predominantly solid with a few scattered anechoic areas; and unilocular cystic masses. Although the prenatal diagnosis could be made with confidence in our cases, the major sonographic differential diagnoses should include anterior or posterior meningomyeloceles, conjoined twins especially in large tumor, hemangioma, neuroectodermal cysts w12x. Ultrasound can usually distinguish SCT from neural tube defects. For type IV Žentirely internal ., the differential diagnosis for this unique presentation of SCT is different from that considered for predominantly external complex tumors. Type 1 Žentirely external. cystic sacrococcygeal teratoma, usually associated with a good outcome following neonatal resection, must be differentiated at the time of prenatal diagnosis from sonographically similar to meningomyeloceles, which carry a grave prognosis. Color Doppler imaging may assist correct midtrimester prenatal diagnosis of a large type 1 cystic sacrococcygeal teratoma closely simulating a meningomyelocele w13x. In addition, elevated maternal serum alpha-fetoprotein may be helpful in diagnosis, however alpha-fetoprotein can be normal or elevated in this condition w5x. Unfortunately, alpha-fetoprotein measurement was not studied in any case of our series.
T. Tongsong et al. r International Journal of Gynecology & Obstetrics 67 (1999) 95]101
Serial ultrasound examinations should be performed during pregnancy to assess amniotic fluid volume, tumor growth, fetal well being, and early evidence of hydrops. Evidence of heart failure, placentomegaly, or hydrops fetalis should be sought because these may progress rapidly like in Case 1. Fetal and placental hydrops are common findings with large SCT. Hydrops may be due to either a combination of high cardiac output failure secondary to the increased vascular bed in the tumor or hypoproteinemia secondary to increased protein loss through abnormal tumor capillaries. Fatal outcome when SCT was associated with hydrops almost always occurred. Case 1 was an example in spite of early diagnosis with only evidence of slightly cardiomegaly and ascites without placentomegaly. Like previous reports, most fetuses with SCT do not reach 36 weeks of gestation because premature delivery is a common complication, with uterine distension from tumor bulk or polyhydramnios being the most likely causes. Warning signs and symptoms of preterm labor should be stressed at prenatal visits and limitation of activity and frequent cervical checks may be indicated. During labor, severe dystocia may occur in infants with large tumors if delivered vaginally, with an extremely high fetal morbidity and mortality rate. The large tumor like Case 1 warranted cesarean section to avoid traumatic delivery. In conclusion, we emphasize that with careful assessment of fetal rump and spine completely in screening for anomaly, SCT can readily be diagnosed even in first trimester and the prenatal diagnosis contributes to changes in management. The successful management of SCT could be achieved with accurate prenatal diagnosis, and early surgical intervention. The role of sonography in the management of these cases should be stressed.
101
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