Uncapsulized sacrococcygeal teratoma in a neonate

Abstract

A full-term female neonate presented with a lumbosacral lesion of intestine-like wet tissue lacking skin coverage (Fig. 1). She was born with a birthweight of 3,534 g and been in a stable general condition. She had no problems moving her legs but a radiograph revealed a sacral anomaly. Investigation with ultrasonography detected a lesion that seemed to be connected to a subcutaneous component. Magnet resonance imaging (MRI) revealed the mass to be localized in the “para”-sacral region, not the “pre”-sacral, as the sacrum was shifted to the right. The mass included solid, cystic, and fatty densities, suggesting a teratoma. Her serum a-fetoprotein (AFP) level was initially measured at 10 days old and found to be 19 548 ng/mL, which was within the reference interval for her age. She also had left ectopic pelvic kidney and lipomyelomeningocele associated with tethered cord (Fig. 2). Her voiding cystourethrography findings were normal, and contrast enema did not indicate any mechanical retractions to the rectum. We performed a partial biopsy of the protruded intestinal mucosa-like tissue. The pathological findings indicated that the lesion comprised a mature glandular epithelium with goblet cells and stratified squamous epithelium. Her lipomyelomeningocele and tethered cord were repaired surgically at 24 days old by pediatric neurosurgeons at our institution. In order to minimize the risk of surgical site infection at neurosurgical intervention we decided to perform the resection of the intestine-like lesion later. During the first operation, a larger specimen of the mucosa-like tissue and a daughter lesion (indicated in Fig. 1) in the lumbar skin were resected. Both of the specimens were pathologically diagnosed as hamartomatous lesions with tissues originating from the fore-gut. With a preoperative diagnosis of either a hamartoma or teratoma, we performed tumor resection at 52 days old. The tumor weighed 5.8 g with diameters of 29 9 20 9 15 mm and was pathologically diagnosed as mature teratoma. The lesion had no connection to the coccyx in findings on CT or during the tumor resection, so we decided coccygectomy was not necessarily applicable. The external part of the lesion was composed of glandular epithelium resembling gastric mucosa. Tissues found internally included cartilage, bone, thyroid, striated muscle, smooth muscle, lymph node, and thymus