Methods

Materials and Methods

A retrospective review was carried out on the records of 16 children with the diagnosis of teratoma treated at Tawam Hospital, Al Ain, United Arab Emirates, between 1986 and 1996. During the same period, 332 children were treated for various types of malignancies, including 197 children with leukemias and lymphomas. The records of those with teratoma were reviewed for age at presentation, sex, mode of presentation, site of teratoma, method of diagnosis, treatment and outcome. The operative procedure and histopathology report were also obtained.

Results

Over a 10-year period, 16 patients with the diagnosis of teratoma were treated at our hospital. The cases included eight sacrococcygeal, four cervical, two ovarian and two retroperitoneal tumors.

Sacrococcygeal Teratomas

Eight patients (50%), comprising seven females and one male, had sacrococcygeal teratomas. Their demographic and clinical features are shown in Table 1. Three of the patients were referred late. One of these was diagnosed at birth but the parents had refused surgery. She had surgery some months later in another hospital and was transferred to our hospital at the age of 18 months because the tumor had recurred, and her alpha-fetoprotein had reached 4028 μg/L. A recurrence measuring 3x2 cm was excised. Histology of the specimen showed it to be a poorly differentiated invasive germ cell tumor. The patient was treated with chemotherapy, and after the second course her alpha-fetoprotein level became normal. Now the patient is 3½ years old, doing well and has no evidence of a recurrence.

Another patient who presented late was referred to our hospital at the age of 18 months, after he had incision and drainage of the sacrococcygeal teratoma, which had been mistakenly diagnosed as an abscess. A 6x2 cm tumor was excised together with the coccyx, and histology of this confirmed malignant teratoma. He was treated with chemotherapy. The patient is now 12 years old and doing well.

The last of the three late-presenting patients came to our hospital at the age of 14 months with sacrococcygeal teratoma that was present at birth but had been increasing in size. She had an MRI, which showed a larger intrapelvic extension, and her alpha-fetoprotein was 980 μg/L. The parents refused surgery.

The other five patients were operated on within four days of their birth. Four of them had well-differentiated teratomas. Histology revealed a mature teratoma covered with normal keratinizing epidermis. In the underlying tissue, cysts covered with regular glandular epithelium, as well as mature cartilage and mature nervous tissue, were seen. No signs of malignancy were observed. The initial histopathology report of the fifth patient showed benign teratoma, but because of increase in her alpha-fetoprotein at the age of six months (Figure 1), she was found to have secondary tumors in the liver, left humerus and left fibula. She had an open liver biopsy and this, as well as review of her initial histology, revealed a malignant teratoma. The sections showed a tumor composed of blastema, which was highly malignant and with glandular differentiated areas. Numerous organoid structures representing all three germinal layers were also present. The mitotic activity was 8-10/high-power field. The patient was started on chemotherapy and showed marked improvement. Now the patient is three years old, doing well, with normal alpha-fetoprotein and secondary tumors having completely disappeared.

Cervical Teratoma

Four patients (two girls and two boys) had cervical teratoma. Their demographic as well as their clinical features are shown in Table 2. Three of them presented with acute respiratory distress necessitating emergency intubation. In one, this was delayed because of difficulty with subsequent brain damage. This patient was referred to us after he had had initial partial resection. Subsequently he had complete resection, but the patient died because of associated severe brain damage. In all the patients the mass was on the left side. In two, the teratoma was so massive and extensive that complete resection in one stage was not possible (Figure 2). One of them had excision of the teratoma in three stages. In all, the teratomas were histologically benign.

Ovarian Teratoma

Two of our patients had ovarian teratoma. A 3½-year-old girl presented with a painful abdominal mass. Abdominal x-ray, ultrasound and CT scan confirmed this to be a 7x6 cm cystic mass arising from the left ovary with some calcification. Alpha-fetoprotein and beta-HCG were normal. During surgery she was found to have a twisted left ovarian tumor with bloodstained fluid in the peritoneal cavity. She had left tubo-ovarectomy, and histology confirmed this to be a benign teratoma. Histology showed a wide variety of tissues, including keratin-filled cysts with many hair follicles, areas of thyroid gland, fat, nerves and ganglia, cartilage, bone and large muscular arteries. There was no evidence of malignant transformation. Now the patient is 5½ years old and doing well. The other patient was a six-year-old who presented with abdominal pain and a mass. There was no calcification of the abdomen on plain x-ray. Abdominal ultrasound revealed a 10x6 cm solid mass arising from the pelvis and to the right side of the abdomen. During surgery the patient was found to have a twisted right ovarian tumor and a streak left ovary. Bilateral salpingo-oophorectomies were done. Histology of the tumor showed it to be a malignant teratoma. Postoperatively, she was treated with chemotherapy. Her postoperative alpha-fetoprotein and beta-HCG were normal, and remained so on follow-up. Five years after the operation, the patient is doing well.

Table 1. Sacrococcygeal teratomas.

 *American Academy of Pediatrics Surgical Section Survey.

Table 2. Cervical teratomas.

 Follow-up ranged from 3.5-10 years (mean 5.8 years).

Retroperitoneal Teratoma

We had two cases of retroperitoneal teratoma. A two-year-old male presented with fever, abdominal pain and a left-sided abdominal mass. His alpha-fetoprotein was 2030 μg/L. Abdominal x-ray showed a soft tissue mass on the left side with calcifications. Abdominal ultrasound and CT scan confirmed a large 17.5x10 cm retroperitoneal mass with a variety of tissues and calcifications. During surgery, he was found to have a very large left retroperitoneal tumor, which was completely excised. Histopathology showed it to be a malignant teratoma. Postoperatively, the patient was started on chemotherapy. His alpha-fetoprotein six months later was 1.8 μg/L. He is now seven years old, asymptomatic and doing well. The other patient was a five-month-old baby referred to our hospital because of a large abdominal mass. Abdominal ultrasound and CT scan showed a large left-sided abdominal mass extending from the anterior abdominal wall to the spine, pushing the liver to the right and upwards, and the stomach to the right. There was no calcification. The patient's alpha-fetoprotein was normal. The mass was excised totally, with part of the stomach and esophagus, which were repaired. Histopathology showed it to be a benign teratoma. Five and a half years after the operation, the patient is doing well.

Discussion

Teratomas, by definition, are tumors that are composed of multiple tissues containing at least two germ-layer derivatives foreign to the part of the body in which they arise. Of all the teratomas seen in infants and children, sacrococcygeal teratoma (SCT) accounts for nearly 40% of all cases.² Even so, sacrococcygeal teratoma is rare, with a reported incidence of 1 in 35,000 to 40,000 live births, and because of this most reported series are small.^3,4 Larger series, on the other hand, are reported from large referral hospitals and usually over a long period. Tapper and Lack² reported 254 patients with teratomas over a 54-year period, and 102 of these were sacrococcygeal teratomas. That is fewer than two cases per year. Similarly, Schropp et al.⁴ reported 73 patients with SCT over a 40-year period, while over a period of 10 years we saw eight patients with SCT. The largest series of SCT was that reported by Altman et al. in 1974.⁵ This was a collective series of 400 cases by the pediatric surgeons of the American Academy of Pediatrics. As a result of this, Altman et al. proposed the classification of SCT based on its extent.⁵

The majority of SCT cases are apparent at birth, and are more common in females, accounting for about 75%.² Only one of our eight SCT patients was a male. The reason for this female preponderance is not known. In SCT, the size of the tumor does not correlate with the likelihood of recurrence or poor outcome,^5,6 but the age at diagnosis and treatment, as well as histological evaluation and stage at the time of resection, are important prognostic factors. Two of our patients, although diagnosed early, had surgery late, and the third who presented late refused surgery. In all, the tumor was malignant, requiring chemotherapy. During surgical resection, the importance of removing the coccyx cannot be overemphasized. A high recurrence rate of up to 37% has been reported where the coccyx had not been excised during the initial procedure.^7-9 Meticulous and careful histological evaluation of SCT is of great importance. One of our patients who was operated on at four days of age and diagnosed as benign teratoma, presented at the age of six months with raised alpha-fetoprotein and was found to have secondaries in the liver and bones. Review of her initial histology showed malignant teratoma. Whether these recurrences were malignant transformations of an original benign lesion or recurrence of a non-diagnosed small foci of malignancy is not known. Alpha-fetoprotein is a well-known marker of teratoma, and valuable during follow-up of patients in whom a recurrence of tumor can be detected even prior to of our patients who, because of raised alpha-fetoprotein on follow-up, was found to have secondary tumors (Figure 1). So a long-term follow-up of patients with SCT is of great importance. This is not only appropriate during the first three postoperative years where recurrence is likely,¹⁰ but also on a long-term basis, as a significant number of them suffer from deficient anorectal function and a diminished quality of life.¹³ Fortunately, in spite of the malignancies reported in three of our patients, one of whom had secondary tumors, none of our patients died, and all were well on follow-up. This is attributed to the recent advances in chemotherapy treatment.

Cervical teratomas are considered to be very rare.^14,15 In a large series of 254 teratomas at various sites observed over a 54-year period, and reported by Tapper and Lack,² 14 (5.5%) were in the head and neck, and only six (2.4%) were cervical. We treated four patients with cervical teratomas over a 10-year period. In a similar report from Riyadh, Saudi Arabia,¹⁶ five cases of cervical teratoma were seen over a 10-year period. This type of teratoma appears to be more common in this part of the world, although the reason for this is not known. Whereas all the patients in the Tapper and Lack study²had right-sided cervical teratoma, our patients, as well as four patients of the Hassab et al.¹⁶ series from Saudi Arabia, had theirs on the left side. Cervical teratomas are commonly seen in the newborn and can attain a large size, leading to severe respiratory distress.^14,16 Prenatal diagnosis in these patients is helpful in planning for their delivery and postnatal care, as this can be life-saving.^14,16 One of our patients was referred to us from another hospital with severe brain damage as a result of difficult intubation. This patient subsequently died. Prior antenatal awareness of this condition and proper planning of delivery would probably have avoided this outcome.

Cervical teratomas in the newborn are almost always benign. This is in contrast to those in adults, but on the other hand, they are locally aggressive. Whereas complete local excision is the treatment of choice, it may not always be feasible. All our patients had benign cervical teratoma, but in two, the teratoma was so extensive that it was not possible to excise in one setting. In these patients, a staged approach may be an alternative. We found CT scan helpful in planning surgical excision in these extensive lesions.

Ovarian teratomas comprise about 37% of all teratomas in infants and children, and are second only to SCT as the most common site for teratoma.² They were, however, comparatively rare in our patients. We saw only two cases. Both patients presented at a younger age, and in both cases a twisted teratoma was found, which is the usual presentation in about one-third of patients with ovarian teratomas.¹¹ About 5% to 10% of ovarian teratomas are malignant.^2,11 Preoperative ultrasound is helpful in predicting the likelihood of the tumor being malignant, as solid tumors are more likely to be malignant. This was the case in one of our two patients. The one that was cystic on preoperative ultrasound was reported to be benign, while the solid one was found to be malignant.

Retroperitoneal teratomas are very rare. They make up less than 5% of all teratomas, and are more commonly seen on the left side,^2,17 which was the case in both our patients. The incidence of malignancy in retroperitoneal teratoma is 6% to 10%.¹⁸ In one of our patients the teratoma was malignant. Surgical excision is the treatment of choice, but in the presence of malignancy this must be supplemented with chemotherapy. Resection was possible in both of our patients. In case the tumor is large and not amenable to resection, adjuvant chemotherapy and/or radiotherapy is advocated, followed by re-exploration.²

References