CHAPTER 35 Sacrococcygeal Teratoma
Step 1: Background and Surgical Anatomy
♦ Sacrococcygeal teratomas (SCTs) are the most common extragonadal germ cell tumors in children. The incidence is approximately 1 in 35,000 live births, with females accounting for 75% of cases.1
♦ SCTs are composed of elements from one or more of the embryonic germ cell layers and contain tissue foreign to the anatomic site of origin. Mature teratomas consist of well-differentiated tissues, whereas immature teratomas contain varying amounts of immature tissue such as neuroectoderm.2 Histologically, teratomas are classified according to their stage of immaturity.3
♦ When the tumor is found before 1 month of age, the risk of malignancy is about 5%, whereas when the tumor is discovered between 1 and 12 months of age, the risk of malignancy is 60%; in children older than 1 year, 75% of tumors are malignant.3
Step 2: Preoperative Considerations
Neonatal
♦ Generally the tumors are noted to have a characteristic mass protruding from the sacral region (Fig. 35-2).
Infant and Pediatric Patients
♦ Generally older children have no external portion noted at birth and present secondary to tumor compression of the bladder or rectum or a palpable rectal mass.
♦ Preoperative evaluation should focus on evaluating the degree of pelvis and abdominal extension by the following:
Clinical assessment: A complete physical examination, including a digital rectal examination to evaluate the presacral region
Radiologic studies: Generally ultrasound is adequate to delineate pelvic or abdominal extension. When a significant abdominal component is identified or concerns arise as to malignant potential, double-contrast computed tomography is useful to demonstrate the relation of the tumor to the rectum and urinary tract, as well as to exclude distant metastasis. Magnetic resonance imaging is particularly useful in evaluating anatomic relation to adjacent structures and possible infiltration into the spinal canal (Fig. 35-3).3
Clinical assessment: A complete physical examination, including a digital rectal examination to evaluate the presacral region
Radiologic studies: Generally ultrasound is adequate to delineate pelvic or abdominal extension. When a significant abdominal component is identified or concerns arise as to malignant potential, double-contrast computed tomography is useful to demonstrate the relation of the tumor to the rectum and urinary tract, as well as to exclude distant metastasis. Magnetic resonance imaging is particularly useful in evaluating anatomic relation to adjacent structures and possible infiltration into the spinal canal (Fig. 35-3).3
Table 35-1 Frequency of Malignancy Associated with Higher American Academy of Pediatrics Anatomic Classification
| AAP TYPE | MALIGNANT (%) | METASTASIS (%) |
|---|---|---|
| I | 8 | 0 |
| II | 21 | 6 |
| III | 34 | 20 |
| IV | 38 | 8 |
Step 3: Operative Steps
Positioning
♦ About 46.7% of SCTs have a significant external component (AAP class I) and can generally be approached in a prone jack-knife position.1 This can be accomplished using a gel roll to support the face and head in neutral position, along with a thoracic gel roll, with the arms in a swimmer’s position. The pelvis is generously elevated using additional gel rolls under the anterior superior iliac spine, with the hips flexed and abducted and the knees slightly flexed and the feet supported with a soft roll (Fig. 35-4).
♦ The balance of SCTs have a significant pelvic or abdominal component (AAP classes II-III) or are contained entirely within the presacral space (AAP class IV). These patients are best approached initially through a supine position, with the dissection beginning in the abdomen.2 Surgical preparation should extend from the nipples to the toes to facilitate intraoperative patient manipulation.
Operative Technique
♦ The abdominal approach through a lower transverse muscle–sparing incision enables mobilization of the pelvic portion of the tumor as well as early ligation of the sacral artery (Fig. 35-5) and access to the distal aorta in very large or vascular lesions.
♦ Use of self-retaining retractors to pack the bowel away from the operative field, followed by lateralization of sigmoid colon, exposes the sacral promontory. Incising the peritoneal reflection with electrocautery at the promontory exposes the median sacral artery, which can be easily ligated at its origin.
♦ Dissection continues inferiorly in the avascular presacral space down to the level of the pelvic floor. The tumor should then be meticulously separated from the rectum with a combination of sharp and blunt dissection by electrocautery. Dissection should take place immediately adjacent to the tumor capsule. Care should be taken to avoid inadvertent division of the levator complex making up the pelvic floor as it is splayed laterally over the SCT.
♦ Lateral and anterior dissection should take place adjacent to the tumor capsule, with care to avoid unnecessary margins that could result in bladder or sexual dysfunction resulting from injury to the sympathetic and parasympathetic nerves.
Posterior Perineal Approach
♦ In a prone jack-knife position, an inverted “V” or inverted chevron incision is made with the apex focused on the sacrococcygeal joint (Fig. 35-6). The incision sweeps inferolaterally around the tumor to encompass the mass and abnormal or ischemic skin.
♦ With the use of electrocautery, dissection is carried down through the subcutaneous tissue down to the tumor capsule posteriorly and gluteal muscles laterally. The gluteal muscles are typically splayed over the SCT and should be retracted laterally to allow mobilization of the tumor with blunt and sharp dissection.
♦ The posterior dissection is carried down to the coccyx, where the coccyx is freed from the sacrum. Care must be taken to identify and ligate the sacral artery if not completed during an abdominal approach. The sacrococcygeal joint is divided with heavy scissors, leaving the coccyx attached to the teratoma.
♦ A large red rubber catheter (10 or 12 Foley) or Hegar dilator may be inserted into the rectum to help guide separation of the tumor from the rectum (Fig. 35-7). Care should be taken to avoid excessive traction on the levator complex.
♦ Wound closure begins with reapproximation of the midline levator to the presacral fascia with interrupted sutures. A passive drain may be placed to avoid seroma formation. Finally, the gluteal muscles are reconstructed in the midline, and excessive skin is excised. The subcutaneous tissue is closed with an absorbable suture, followed by a subcuticular absorbable skin closure (Fig. 35-8).
Step 4: Postoperative Care
♦ Antibiotic prophylaxis is not necessary postoperatively. Surgical drains (if placed) should be removed on postoperative day 2 or 3 or when drainage is minimal.
♦ Initiation of enteral feeds may be commenced on return of bowel function and advanced to enteral goals as tolerated.
♦ Neonates with mature and immature teratomas are managed with observation, with predicted recurrence rates of 10% to 21% after complete resection of SCT.2
♦ Tumor recurrence should be treated with surgical resection where feasible, and the patient should be treated with multiagent chemotherapy.5
♦ Older patients frequently have unresectable lesions. After initial biopsy, these patients should undergo neoadjuvant platinum-based chemotherapy, followed by delayed surgical resection.2
♦ Follow-up should entail the following:
Step 5: Pearls and Pitfalls
♦ Preoperative imaging is crucial in assessing respectability, directing surgical positioning, and excluding unexpected findings, such as myelomeningocele, spinal defects, and urinary tract obstruction.
♦ Utilization of a large red rubber catheter or Hegar dilator placed into the rectum may greatly facilitate safe dissection of the tumor from the rectum.
♦ Early identification and ligation of the median sacral artery enable early vascular control and minimize intraoperative blood loss (see Fig. 35-5).
1 Rescorla FJ, Sawin RS, Coran AG, et al. Long-term outcome for infants and children with sacrococcygeal teratoma: a report from the Childrens Cancer Group. J Pediatr Surg. 1998;33(2):171-176.
2 Rescorla FJ. Pediatric germ cell tumors. Semin Surg Oncol. 1999;16(2):144-158.
3 Skinner MA. Germ cell tumors. In: Keith T, Oldham PMC, Foglia RP, Skinner MA, editors. Principles and practice of pediatric surgery, vol. 1. Lippincott Williams & Wilkins; 2005:637-648.
4 Altman RP, Randolph JG, Lilly JR. Sacrococcygeal teratoma: American Academy of Pediatrics Surgical Section Survey-1973. J Pediatr Surg. 1974;9(3):389-398.
5 Rescorla F, Billmire D, Stolar C, et al. The effect of cisplatin dose and surgical resection in children with malignant germ cell tumors at the sacrococcygeal region: a pediatric intergroup trial (POG 9049/CCG 8882). J Pediatr Surg. 2001;36(1):12-17.
6 Currarino G, Coln D, Votteler T. Triad of anorectal, sacral, and presacral anomalies. AJR Am J Roentgenol. 1981;137(2):395-398.
7 Boemers TM, van Gool JD, de Jong TP, Bax KM. Lower urinary tract dysfunction in children with benign sacrococcygeal teratoma. J Urol. 1994;151(1):174-176.
