Sacrococcygeal teratomas are congenital neoplasms with a prevalence of 1 in 40,000 live births.^1,2 These lesions are rarely encountered in adults, and their size and location vary. Microscopically, teratomas are often disorganized and contain differentiated tissues from all three germ cell layers. Although these lesions are usually benign, the risk of malignant transformation increases significantly with advancing age. When teratomas recur, they tend to do so within 2 years of resection. We report the unusual case of a sacrococcygeal teratoma that recurred 20 years after it was initially resected and recurred a third time 17 years following the second resection.

CASE PRESENTATION

Figure 1—Abdominopelvic CT scan showing an 11 x 13-cm cystic presacral mass exerting significant mass effect and displacing the uterus, rectum, and bladder.

A 37-year-old woman presented to the outpatient clinic after her primary care physician was unable to perform a complete pelvic examination because of a large pelvic mass. The mass distorted the vaginal vault and precluded the uterus, adnexa, and cervix from being clinically assessed. No other abnormalities were identified during the patient's physical examination, but she reported having experienced progressive urinary frequency, nocturia, and constipation over a 2-year period. A computed tomography (CT) scan showed an 11 x 13-cm cystic presacral tumor that was exerting significant mass effect and displacing the patient's uterus, rectum, and bladder (Figure 1). Her surgical history was significant for excision of a benign retroperitoneal teratoma when she was a newborn. The lesion recurred 20 years later in the presacral region, at which time she underwent a suboptimal re-excision that was complicated by significant blood loss.

On presenting to our clinic, the patient was admitted to the gynecology service to have the mass embolized prior to exploratory laparotomy. Following embolization she underwent bilateral ureteral stent placement, total abdominal hysterectomy, left salpingo-oophorectomy lysis of adhesions and suboptimal removal of the retroperitoneal mass (Figure 2) during a 10-hour operation. Despite preoperative embolization the surgery was complicated by a myocardial infarction and significant blood loss and perioperative blood transfusions were needed.

Figure 2—Photomicrograph of the resected sacrococcygeal teratoma showing squamous epithelium and a small area of hyperplasia; no immature elements are visible.	Figure 3—Photomicrograph of the sacrococcygeal biopsy specimen showing mucinous material with areas of colonictype mucinous epithelium.

At 4-month follow-up a large pelvic mass was palpated. Imaging confirmed that the residual pelvic mass had enlarged significantly. The mass contained focal areas that appeared more solid when compared with the previous preoperative study. These solid components were thought to consist of soft tissue or debris. A subsequent biopsy of the sacrococcygeal area revealed a mucinous tumor of low malignant potential (Figure 3). The findings were discussed with the patient, but she declined additional operative intervention because of her complicated intraoperative course, and expectant management was offered.

DISCUSSION

Sacrococcygeal teratomas are rare tumors that usually occur sporadically. They are thought to originate from multipotential cells in Hensen's node, which migrate caudally to the coccyx. Sacrococcygeal teratomas have a prevalence of 1 in 40,000 live births and a female predominance of 4 to 1.^1,2 Most lesions are benign, but the likelihood of malignancy increases with age. There is a 2% to 5% risk of malignancy in neonates with teratomas, and this risk increases exponentially to 50% by 1 year of age.³ Nearly all unresect-ed congenital teratomas identified in patients older than 5 years are malignant. Less than 1% of these tumors persist into adulthood and, interestingly, most are benign. Only 1% to 2% of sacrococcygeal teratomas diagnosed in adults are malignant, with the most common malignancy being endodermal tumors.

Symptoms, diagnosis, and classification
Presacral teratomas are usually diagnosed expediently in neonates. Diagnosis can be more challenging in adults, whose symptoms are often subtle. Pressure symptoms, such as constipation, nocturia, and urinary frequency, are common, and our patient experienced all these symptoms over a 2-year period. Other known symptoms include lumbago, lower extremity paresthesia, and weakness.

Evaluating sacrococcygeal teratomas requires performing a thorough physical examination and conducting imaging studies. CT scanning and magnetic resonance imaging (MRI) are useful modalities because they provide information about the dimensions of the mass. They also show its relationship to other pelvic and non-pelvic structures, which helps to classify the lesions.

Sacrococcygeal teratomas contain either mature or immature elements from more than one germ cell layer and are classified histologically either as immature without malignant features or overtly malignant. They are also classified according to how much tumor lies outside of the body (Table). Type IV teratomas are completely intrapelvic. They are the most difficult to diagnose and treat and more likely to be malignant. Patients with type IV tumors tend to present later than those whose teratomas have an external component.

Treatment and recurrence
Sacrococcygeal teratomas are generally excised, using a posterior sacral approach for tumors smaller than 8 to 10 cm or an abdominosacral approach for tumors larger than 10 cm. Many teratomas are large and vascular, and preoperative embolization of such neoplasms is recommended. Excessive blood loss and incomplete resection of the mass are the most common surgical complications, and these are more likely to occur in patients with type III and type IV tumors.

Our case and others in the literature show that sacrococcygeal teratomas can recur decades later. The intrapelvic portion of a teratoma often creates the nidus for regrowth after an attempted resection. The coccyx is also a potential nidus for recurrence and should be resected.⁴ Failure to resect the coccyx is associated with recurrence rates as high as 33% to 37%.⁵ Our patient, who was first diagnosed and treated as an infant, never underwent radical excision. Her disease recurrences at 20 years and 37 years of age may have resulted from persistence of the slow-growing neoplasm. Tumor markers have no value in managing benign and non-germ cell recurrences, but the alpha fetoprotein level is a reliable marker for the endoder-mal subtypes seen in infancy and may be elevated in endodermal recurrences.⁶

Patients whose initial lesions are benign can develop malignant recurrences. Although this is extremely rare and a poorly understood phenomenon, clinicians should suspect malignancy whenever a recurrence is discovered, regardless of the patient's previous histology results. Our patient underwent three resections over three decades, and pathologic evaluation identified all three tumors as benign. Her fourth recurrence, diagnosed more than 37 years after excision of the initial tumor, was classified as a mucinous tumor with low malignant potential.

Incomplete resection of malignant tumors is associated with poor prognosis. Even after complete resection, patients treated for malignant disease have an increased risk of malignant recurrences. Several chemotherapeutic regimens have been successfully employed in children with malignant lesions, along with radiotherapy and surgical excision.

Close postoperative follow-up of patients who have undergone radical excision of either a benign or malignant sacrococcygeal teratoma is imperative. Monthly examinations should be conducted in the first year, with additional periodic physical examinations over the next 2 years. Lifelong rectovaginal examinations and imaging studies, when indicated, may be plausible options in treating these patients.⁷

CONCLUSION

Our patient was treated for a sacrococcygeal teratoma as a newborn, which recurred three times over the next 37 years and eventually progressed from a benign tumor to a mucinous one of low malignant potential. Most recurrences of sacrococcygeal teratoma occur in childhood,⁸ but our patient's first two recurrences were diagnosed at age 20 and age 37, respectively, indicating significantly delayed tumor growth. The rarity of sacrococcygeal teratoma has resulted in a paucity of data, and there is no standard protocol for treating patients who have this disease. More studies are needed to assist clinicians in determining the optimal care of these patients.

References

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