Teratomas, Dermoids, and Other Soft Tissue Tumors

Diagnosis

Most SCTs are seen as a visible mass at birth, making the diagnosis obvious ( Fig. 67.5 ). Prenatal diagnosis has important implications and will be discussed further.

There is an unexplained female preponderance of 3:1. The main differential diagnosis is meningocele. Typically, meningoceles occur cephalad to the sacrum and are covered by dura, but sometimes they are covered by skin. Examination of the child reveals bulging of the fontanelle with gentle pressure on a sacral meningocele, helping to establish the diagnosis before plain radiography, US, and magnetic resonance imaging (MRI) confirm it. The coexistence of meningocele with teratoma is well recognized in the familial form, but the teratoma is usually presacral. Rarely, a typical exophytic teratoma may have an intradural extension. Other lesions in the differential diagnosis of neonatal sacrococcygeal masses include lymphangiomas, lipomas, tail-like remnants ( Fig. 67.6 ), meconium pseudocysts, rectal duplications, and several other unusual conditions.

Although many neonates with SCTs do not have symptoms, some require intensive care because of prematurity, high-output cardiac failure, disseminated intravascular coagulation, and tumor rupture or bleeding. Lethal hyperkalemia from tumor necrosis has been described. Lesions with a large intrapelvic component can cause urinary obstruction. Besides looking for signs of a myelomeningocele, the physical examination should always include a rectal examination to evaluate for an intrapelvic component. The ability to feel an intact sacrum above the level of the mass is an indication that complete resection in the prone position will be achievable. The most helpful imaging studies consist of plain anteroposterior and lateral radiographs of the pelvis and spine, looking for calcifications in the tumor and for spinal defects, and US of the abdomen, pelvis, and spine. Further preoperative studies are unnecessary in most newborns.

The diagnosis of a purely intrapelvic teratoma is often delayed. Children develop constipation, urinary retention, an abdominal mass, or symptoms of malignancy, such as failure to thrive. Age is a predictor of malignancy in patients with testicular, mediastinal, and SCTs. The risk of malignancy is less than 10% at birth but rises to 40–75% after age 1 year for SCTs, with the exception of those seen as part of the Currarino triad and familial presacral teratomas. The risk of malignancy also is high for incompletely excised lesions. Complete excision of the tumor should be carried out as soon as the neonate is stable enough to undergo the operation. Serum markers should be determined before the operation for later comparison.

Prenatal Diagnosis

In recent decades, the diagnosis has often been made on prenatal US, especially when this examination is routinely performed in the second trimester. The site of the lesion, its complex appearance, and intrapelvic extension with or without urinary tract obstruction are easily recognized. Although most small teratomas do not adversely affect the fetus, the presence of a large solid vascular tumor is associated with a significant mortality rate, both in utero and perinatally. Perinatal mortality is usually related to prematurity or tumor rupture with exsanguination (or both). Premature delivery may occur spontaneously from polyhydramnios or may be induced urgently because of fetal distress or maternal pre-eclampsia.

Repeated US assessment of tumor size is important because the fetus should be delivered by cesarean section if the tumor is larger than 5 cm or larger than the fetal biparietal diameter. Dystocia during vaginal delivery is associated with tumor rupture and hemorrhage and is an avoidable obstetric nightmare. The options in managing unexpected cases with dystocia include emergency cesarean section of the partially delivered fetus who has been intubated and ventilated after vaginal presentation of the head.

Polyhydramnios with larger tumors may lead to premature labor, and amnioreduction is often needed to decrease uterine irritability. Tumors that are larger than the fetal biparietal diameter at diagnosis, that grow faster than the fetus, or that grow faster than 150 mL/week are associated with a poor prognosis. As the tumor enlarges, the fetus may develop placentomegaly or hydrops, caused by high-output cardiac failure from vascular shunting within the tumor, with fetal anemia from intratumoral bleeding also playing a role. Early signs of cardiac failure can be recognized by Doppler US and fetal echocardiogram (discussed later in this chapter). Placentomegaly and hydrops are harbingers of impending fetal death and should lead to urgent cesarean delivery. Open fetal surgical excision/debulking is one option in fetuses considered too premature to deliver. It has been performed with success in three of eight cases in one center and in three of four cases in another. However, in the presence of the maternal mirror syndrome, emergency cesarean delivery is indicated to prevent life-threatening maternal complications. Interestingly, there were no cases of fetal resection in the latter center in a more recent cohort of 23 fetuses with SCT, emphasizing that the indications for such a procedure are limited once selection criteria have been refined.

As a result of the maternal and fetal risks, less invasive therapeutic options have been sought. Successful intrauterine endoscopic laser ablation of the large feeding arteries has been described. There have been several other reports, a few with good outcomes, but some with poor outcomes, often related to severe fetal anemia and cardiac failure. Alcohol injection has also been tried. Attempts at interrupting the high vascular flow have been described by using radiofrequency ablation (RFA), with two survivors in the first four attempts. One survivor had significant perineal damage. As the technology has improved, there seems to be a renewed interest in this technique. A recent case series and systematic review found a total of 20 fetuses treated for SCT with hydrops with various minimally invasive therapies. However, it remains unclear when early delivery is preferable to intervention in utero in fetuses with early hydrops and placentomegaly. Some advocate fetal surgery before 30 weeks of gestation, with the same group recently suggesting early delivery in selected fetuses after 27 weeks of gestation. Others have reported survival after emergency delivery as early as 26 weeks of gestation. The ex utero intrapartum treatment (EXIT) procedure has been used as an adjunct to allow safer resection of a ruptured teratoma in a 27-week-gestation fetus, but long-term neurologic sequelae were noted.

Purely cystic teratomas occur in 10–15% of cases. Prenatal diagnosis allows percutaneous aspiration to facilitate delivery ( Fig. 67.7 ), decrease uterine irritability, or prevent tumor rupture at delivery. In another report, prenatal decompression using a cyst-amniotic shunt was successfully performed to relieve the obstructive uropathy caused by the cystic teratoma. Fetal MRI is a useful adjunct to the prenatal evaluation, providing additional information that helps in counseling and preoperative planning. It also helps in the differential diagnosis when the teratoma is entirely presacral.

Operative Approach

Adequate intravenous access, preferably in the upper extremities, and the availability of blood products should be ascertained before starting the operation, especially with large tumors.

For most tumors, the major component is extrapelvic and the patient is placed in the prone position. If there is a significant intrapelvic or intra-abdominal component, or if the tumor is highly vascular and bleeding within the tumor is suspected, it may be wise to begin with a laparotomy or laparoscopy. Generally, most resections can be achieved completely in the prone position, especially if the internal portion is cystic ( Figs. 67.8 and 67.9 ). When in doubt, a safe approach is to prepare the skin from the lower chest to the toes, allowing the infant to be turned to the supine position without having to re-drape. Vaseline packing in the rectum facilitates its identification throughout the procedure. En bloc excision, including the coccyx, is preferable. Failure to remove the coccyx is associated with a high recurrence rate. An acceptable gluteal crease and perineum is formed by the appropriate reconstruction of the perianal musculature. The use of plastic surgical principles to close the skin improves the cosmetic appearance of the scar (see Fig. 67.8 , inset).

Although the chevron incision has been used by most surgeons, a vertical incision is sometimes possible. It is preferred for smaller teratomas because it leaves a nearly normal-looking median raphe ( Fig. 67.10 ). Resection of the excess skin at the closure gives an optimal cosmetic result. Others have reported using this approach for large tumors.

Several techniques have been described to help in the management of giant SCTs. These include intraoperative snaring of the aorta, laparoscopic division of the median sacral artery, the use of extracorporeal membrane oxygenation and hypothermic perfusion, devascularization and staged resection, and preoperative embolization with or without RFA. Autologous cord blood transfusion is another useful adjunct.

For patients with Currarino syndrome, the presacral mass can usually be resected through a posterior sagittal approach. The teratoma is often densely adherent to the rectal wall in such patients, and the surgeon should not be overly aggressive in the absence of malignancy. When an anterior meningocele or other anomaly of the terminal spinal cord is associated, a combined approach with a pediatric neurosurgeon is ideal. Some have also advocated simultaneous repair of the anal anomaly, resection of the presacral mass, and neurosurgical repair, but in our experience the anal anomaly either did not require a surgical approach or was treated before recognition of the presacral mass.

Prognosis

Fetuses with an SCT diagnosed in utero have a survival rate in excess of 90% if the tumors are small and discovered by routine prenatal US. If a complicated pregnancy is the indication for US evaluation, the mortality increases to 60%. Nearly 100% of patients die when hydrops or placentomegaly develops. Dystocia and tumor rupture during delivery are likely underreported as a cause of mortality. In one series, 10% of patients died during transfer, all before the widespread use of antenatal US. In a report of 24 patients with an SCT diagnosed on routine obstetric US, three were aborted electively, four died in utero at 20–27 weeks of gestation, and three died of tumor rupture during delivery at 29–35 weeks of gestation (one after vaginal and two after cesarean delivery). The incidence of placentomegaly (none), hydrops (5%), and polyhydramnios (19%) was lower than in series in which US was performed for an obstetric reason.

Tumor size, vascularity, and content have been used to develop a prognostic classification from a cohort of 44 fetal SCTs. There was a 50% mortality with tumors 10 cm or greater that were highly vascular or fast growing, whereas no patient died if these features were absent or if the tumor was predominantly cystic. Abnormal umbilical artery Doppler studies were predictive of fetal death in a 2004 report, but a more recent report from the same center suggested that the use of combined cardiac output of ≥600 mL/kg/min and early signs of hydrops were better indications of fetal physiologic compromise. They also found that an SCT growth rate of ≥150 mL/week was associated with an increased risk of perinatal mortality. Another prognostic classification involves the ratio of solid tumor volume over the head volume. In a series of 28 cases, none of the fetuses with solid tumor volume/head volume (STV/HV) ratio <1 died and 61% with a ratio >1 died. The same center also reported risk stratification based on fetal echocardiographic findings. More recently, the ratio of tumor volume to fetal weight was found to be another early prognostic marker, with a cut-off of 0.12 before 24 weeks of gestation. It has since been validated in other centers and appears to emerge as the simplest and easiest prognostic marker to use, together with tumor morphology (solid vs cystic). Fetuses with hydrops and other signs of poor prognosis who are too premature for delivery may be salvaged by fetal intervention. In a recent systematic review, survival after all types of minimally invasive therapies was 30% (6/20), 45% (5/11) when evaluating only RFA or interstitial laser ablation, and 55% (6/11) after open fetal resection, with a similar gestational age at delivery just under 30 weeks for all techniques.

In the absence of severe prematurity and perinatal complications, the prognosis depends on the presence of malignancy and is therefore related to age at operation and completeness of resection. When the tumor is benign and completely excised, the recurrence rate is low, unless the tumor is large and mostly solid. The recurrent tumor may be benign or malignant, and benign metastatic tissue may become evident in lymph nodes. Although immature or fetal elements in gonadal teratomas are associated with a higher risk of aggressive behavior, this is not considered true for SCTs. However, a multicenter study identified immature histology, malignancy, and incomplete resection as risk factors for recurrence. Although malignant recurrence of a “benign” teratoma may be as high as 10–15%, the original benign diagnosis may have been the result of sampling error, due to an undetected residual microscopic focus of malignant tumor, or secondary to incomplete coccygectomy at the initial operation. Patients whose tumors are resected after the newborn period have a higher risk of malignant recurrence, especially when an elevated AFP level is present at diagnosis. The elevated AFP likely signifies the presence of malignancy in the original tumor. It is important to monitor all patients with physical examination, including rectal examination and serum markers (AFP and CA 125), every 2 or 3 months for at least 3 years, because most recurrences occur within 3 years of operation.

Recurrent disease is usually local, but metastases to inguinal nodes, lung, liver, brain, and peritoneum can occur, including pseudomyxoma peritonei. The prognosis of the child with a malignant tumor or a malignant recurrence was dismal until the advent of platinum-based chemotherapy. Survival rates higher than 80–90% are now achieved, even in the presence of metastatic disease, but the risk of late recurrences or second malignancies persists. Older patients presenting with large malignant tumors usually undergo biopsy followed by chemotherapy before resection is attempted, in order to avoid sacrificing vital structures.

A Children’s Cancer Group (CCG) review illustrates the shift in mortality causes, from late diagnosis/malignancy to perinatal events. The mortality was 10% in 126 patients treated in 15 institutions from 1972–1994. Three patients died of severe associated anomalies. Two died of hemorrhagic shock postoperatively and 6 due to combinations of severe prematurity, birth asphyxia as a result of failed vaginal delivery, or preoperative tumor rupture. Death from a metastatic YST occurred in 1 patient. A second patient with metastatic disease was lost to follow-up and is presumed dead. Thus, only 2 deaths occurred from malignancy, despite a total of 20 YSTs (13 malignant at initial operation, 7 malignant recurrences after resection of “benign” teratomas). Owing to the effectiveness of current chemotherapy in treating recurrent disease, as well as its toxicity in young infants, it appears that a completely excised malignant YST does not require adjuvant therapy. These patients should be closely monitored clinically and with serial AFP measurements. Similar encouraging results were seen in the German Cooperative Studies. In another multicenter study spanning from 1970–2010, the postnatal mortality was 7.7%, with half of the deaths being related to malignancy and the other half occurring in the neonatal period, mostly from hemorrhage, which correlated with larger tumor size.

In the current era with the rather routine use of US in pregnancy, the prognosis for patients with an SCT is not dependent on the Altman classification, but rather on tumor size, physiologic consequences, histology, and associated anomalies. The prognosis of malignant tumors depends on tumor type, stage, location, and patient age. Functional results in survivors have been reported as excellent in many series. However, several reports draw attention to fecal and urinary continence problems, as well as lower limb weakness; the most frequent complaints were soiling, constipation, and urinary incontinence. Some of these problems are clearly related to associated anomalies, the need for reoperation, or to the presence of large presacral or intra-abdominal tumors, but they can occur after excision of purely extrapelvic benign tumors. In one study, anorectal and urologic complications were more common when prenatal imaging suggested intestinal or urologic obstruction. One group advocates earlier cesarean delivery to minimize urologic sequelae in patients with large tumors causing urinary tract dilatation. Others have placed vesico-amniotic shunts in such cases with good outcomes. Urodynamic studies and surveillance US are now being performed more regularly in some centers. Patients with Currarino syndrome, who often have a tethered cord in addition to the presacral tumor, appear to have an increased risk of bladder and bowel dysfunction. The bowel dysfunction is remarkably difficult to manage in these patients and has been compared with chronic intestinal pseudo-obstruction by one group. In another study a poor urologic outcome was seen only when lipomyeloschisis was present.

For SCTs in general, a poor cosmetic result was noted in more than half of the patients in one review, whereas others found low levels of appearance-related psychosocial distress. The technique described by the Boston Children’s group is a significant step in improving cosmesis (see Fig. 67.8 ), whereas others favor a sagittal incision. The potential for normal fertility and vaginal delivery appears preserved. Despite all these reported sequelae, the long-term quality of life does not appear to differ from that of the general population. The same was true in a cohort of patients requiring chemotherapy for malignant SCT, although they suffered from physical limitations such as hearing loss. A good outcome requires meticulous dissection along the tumor capsule, preservation and reconstruction of muscular structures, and long-term follow-up. Many authors advocate early assessment of bladder, anorectal, and sexual function along with cosmetic results within a structured oncology follow-up program.

Mediastinal Teratomas

Mediastinal teratomas are diagnosed from the fetal period to adolescence and even adulthood. Most are located in the anterior mediastinum, but a few have been described in the posterior mediastinum, some with epidural extension. Although infants commonly present with respiratory distress, lesions in the fetus can present with hydrops and evidence of airway compromise on prenatal imaging. In older children, teratomas are often an incidental finding on a chest radiograph ( Fig. 67.11 ). Any patient with a mediastinal mass that presents with orthopnea or a reduction in the tracheal cross-sectional diameter of greater than 50% on axial imaging is at a significant risk for airway collapse during general anesthesia. In these cases, procedures using local or regional anesthesia may be required to obtain a confirmatory diagnosis. Mediastinal teratomas may be first seen as a chest wall tumor and may even erode through the skin. They also can erode into a bronchus, with hemoptysis as the initial manifestation, or rupture into the pleural cavity. Secondary pericardial effusion and tamponade also have been described. As mentioned, a strong association is found with Klinefelter syndrome. In these cases, choriocarcinoma within the teratoma often leads to precocious puberty (see Associated Anomalies). Mediastinal germ cell tumors have been observed concurrently or after treatment for hematologic malignancies such as Langerhans cell histiocytosis and hemophagocytic syndrome. Histologically, the presence of immature tissue does not affect the prognosis in children younger than 15 years. After age 15 years, mediastinal teratomas have a high incidence of malignant behavior, which is usually indicated by elevated levels of AFP or β-hCG (or both). For those with malignancy, YST is most prevalent in girls and young boys, whereas mixed histology prevails in over 50% of older adolescent males.

Large tumors should be excised through either a median sternotomy or a thoracotomy. Smaller tumors may be approached through an anterior mediastinotomy (see Fig. 67.11 ) or by thoracoscopy, although tumor seeding is a concern with the latter. Complete resection is the goal, but often these masses are too large at presentation and thus require initial biopsy followed by chemotherapy. During chemotherapy, attention should be paid to the “growing teratoma syndrome” that occurs when the benign elements within a germ cell tumor continue to grow. A Pediatric Oncology and Children’s Cancer (POG/CCG) intergroup study involving 38 patients demonstrated that primary resection could be achieved in only 14 patients. In another 18, chemotherapy reduced tumor size in 57% while the remainder were stable or increased in size. All patients with residual disease underwent successful post-chemotherapy resection. The overall survival for malignant mediastinal germ cell tumors in this study was 71%, which is less than for other extragonadal sites. In a more recent study, the Italian Association of Pediatric Hematology and Oncology reported an overall survival of more than 80% in 20 consecutive pediatric patients. These results support previous studies demonstrating better prognosis with younger patients (i.e., young children with YST) compared with older adolescents (i.e., with with mixed germ cell histology). Importantly, this variance in outcome is thought to be the result of differences in the cytogenetic and molecular profiles of these tumors based on patient age and the germ cell development stage in which these tumors occur. In a recent series from Memorial Sloan-Kettering Cancer Center, normalization or reduction in preoperative tumor markers was the strongest predictor of increased survival.

Although rare, the management of prenatally diagnosed mediastinal teratomas deserves special mention. Merchant et al. described the management of such lesions based on gestational age (GA) and the presence of either hydrops and/or airway compromise in a small clinical report. Less than 30 weeks GA fetuses were managed by in-utero resection. Fetuses older than 30 weeks GA with hydrops and airway compromise were delivered by EXIT. If ventilation was not possible after intubation, resection was completed on placental support. Those who could be placed on a ventilator were then treated with postnatal resection. A report from Japan also described prenatal aspiration of the cystic contents of a mediastinal teratoma at 29 weeks GA, leading to resolution of the hydrops. This baby was born without respiratory distress and underwent postnatal resection with a good outcome.

Intrapericardial Teratomas

Intrapericardial teratomas are most commonly seen in the newborn period or in utero, with evidence of cardiorespiratory distress secondary to pericardial effusions or nonimmune fetal hydrops resulting from cardiac compression. Although a fetal diagnosis allows for early postnatal treatment in most patients, it may also offer an opportunity for antenatal interventions such as fetal pericardiocentesis. Early delivery for emergency surgical excision should be considered if the baby develops signs of cardiac tamponade. Intrapericardial teratomas are also the leading cause of massive pericardial effusion in the neonate, and any delays in diagnosis could be fatal. In older infants, it may manifest with respiratory distress or poor feeding. US usually demonstrates a cystic or solid teratoma located anterior to the right atrium and ventricle with attachments to the great vessels (see Fig. 25.8 ). The tumor also may be found incidentally on chest radiographs performed for other reasons. The only treatment for this lesion is surgical excision. On histologic examination, these teratomas are usually composed of mature tissue with or without neuroglial elements, although there have been reports of these lesions containing YST.

Intracardiac Teratomas

Intracardiac teratomas are rare and arise from the atrium or ventricle. Many can be cured by surgical resection.

Pulmonary Teratomas

Few cases of intrapulmonary teratoma have been described. Symptoms include trichoptysis or hemoptysis. Lobectomy is the usual treatment.

Retroperitoneal Teratomas

Retroperitoneal teratomas occur outside the pelvis, often in a suprarenal location. They represent about 4% of all childhood teratomas, and 75% occur in children younger than 5 years. They occur twice as frequently in females and also have an association with Klinefelter syndrome. Although more than 90% are benign, up to one-quarter may be malignant when diagnosed in the first month of life. Usually the tumor is discovered as an abdominal mass that compresses the gastrointestinal tract, causing symptoms such as vomiting, difficulty feeding, and constipation. Presentation with an acute abdomen from infection also has been described. Abdominal radiographs may show calcifications or bony structures within the tumor ( Fig. 67.12 ). US, cross-sectional imaging (i.e., CT scan or MRI), and the assessment of serum markers are the essential aspects of preoperative evaluation. Operative excision is usually straightforward, but occasionally the tumor may encase major vessels and adjacent viscera, making resection difficult and complicated. Malignant lesions manifest as bulky masses that are not easily resectable. In a POG/CCG intergroup study involving 25 patients, only 5 could be resected primarily. The remainder underwent initial biopsy and platinum-based chemotherapy, of which 4 did not require further surgery. The remaining patients in this series underwent total or partial resection with a 6-year event-free survival of over 80% and an overall survival close to 90%. The retroperitoneum is also the most common site for the fetus-in-fetu malformations and intermediate fetiform teratomas.