Epidural metastases from endodermal sinus tumor arising from benign sacral teratoma. Case report and review of the literature.

The recurrence of benign sacral teratomas is a small but significant possibility. Recurrence as an endodermal sinus tumor (EST) with epidural metastases, however, has not been previously reported. The authors describe a case of a mature sacrococcygeal teratoma in a 4-day-old female patient that recurred after 22 months as an EST with epidural metastases. The child presented with abdominal pain, urinary retention, and difficulty walking. On imaging, a large pelvic mass and an epidural spinal mass were revealed. The patient's alpha-fetal protein (AFP) level was 68,000 ng/ml. Her neurological examination was significant for 3/5 plantar and dorsiflexion strength bilaterally. The patient underwent L-3, L-4, and L-5 bilateral laminectomies followed by subtotal resection of the recurrent pelvic tumor. Pathological testing of samples of both the recurrent pelvic and the extradural spinal tumors led to a diagnosis of EST. The patient underwent four cycles of chemotherapy with normalization of her AFP level to 13 ng/ml. In the weeks that followed, her AFP level steadily rose again to 167 ng/ml. Follow-up imaging revealed no tumor recurrence. The patient underwent a second course of chemotherapy followed by two tandem courses of high-dose chemotherapy with autologous stem-cell rescue. Since completing this therapy the patient has been clinically stable with an AFP level of 1.3 ng/ml for 14 months. At the 1-year follow-up examination, her plantar and dorsiflexion strength had markedly improved to 4+/5 bilaterally. To the authors' knowledge, this is the first case of a mature sacrococcygeal tumor that recurred as an EST and caused spinal canal compromise.