Case Report Prenatal Diagnosis of Tethered Spinal Cord Associated with Sacrococcygeal Teratoma Tugba Sarac Sivrikoz, MD, 1 Recep Has, MD, 1 Aytul Corbacioglu Esmer, MD, 2 Ibrahim Kalelioglu, MD, 1 Atil Yuksel, MD, 1 Orhun Cig Taskin, MD 3 1 Division of Maternal-Fetal Medicine, Department of Obstetrics and Gynecology, Istanbul Faculty of Medicine, Istanbul University, Istanbul, Turkey 2 Division of Maternal-Fetal Medicine, Department of Obstetrics and Gynecology, Kanuni Sultan Suleyman Research and Teaching Hospital, Istanbul, Turkey 3 Department of Pathology, Istanbul Faculty of Medicine, Istanbul University, Istanbul, Turkey Received 22 December 2015; accepted 20 January 2016 ABSTRACT: Tethered spinal cord is mostly caused by myelomeningocele and lipomyelomeningocele, while dermal sinus tract, diastematomyelia, lipoma, tumor, thickened/tight filum terminale, spinal trauma, and spinal surgery are among the other causes. Prenatal diagnosis of tethered cord has been reported, and it is usually associated with neural tube defects. We pres- ent an atypical presentation of a tethered spinal cord, which was associated with a sacrococcygeal teratoma and was diagnosed in the 23rd week of pregnancy by ultrasonography. V C 2016 Wiley Periodicals, Inc. J Clin Ultrasound 00:000–000, 2016; Published online in Wiley Online Library (wileyonlinelibrary.com). DOI: 10.1002/jcu.22344 Keywords: tethered spinal cord; sacrococcygeal tera- toma; fetal spine; fetal spinal cord; conus medullaris; ultrasonography; obstetrics INTRODUCTION T ethered spinal cord (TSC) is defined as the fixation of the caudal portion of the spinal cord, which results in a tight pull or stretching on the lower portion of the spinal cord and can lead to neurologic compromise. It is mostly caused by myelomeningocele and lipomyelome- ningocele, while dermal sinus tract, diastemato- myelia, lipoma, tumor, thickened/tight filum terminale, spinal trauma, and spinal surgery are other causes of TSC. The true incidence of primary TSC is not known, and it is usually diagnosed with the onset of symptoms. Prenatal diagnosis of TSC is possible, and it is typically associated with neural tube defects (NTDs). 1 We report an atypical presentation of TSC, which was associated with a sacrococcygeal teratoma and diagnosed in the 23rd week of pregnancy by ultrasonography. CASE REPORT A 30-year-old woman, gravida 1, para 0, was referred to our clinic in the 23rd week of gesta- tion after a sonographic examination of the fetus revealed a mass in the sacral region. Detailed sonographic examination was performed using a 2–5-MHz curved-array transabdominal trans- ducer and a 5–13 MHz endovaginal transducer connected to a Voluson E8 scanner (GE Health- care, Milwaukee, WI). Sagittal scans showed a 4.5-mm vertebral defect in the sacrum and a small cystic mass. This cystic mass was associ- ated with the conus medullaris, which was stretched out through the vertebral defect, sug- gesting the diagnosis of TSC (Figure 1). In the axial plane, another solid mass measuring 36 3 28 3 27 mm was observed. This mass was connected by a 10-mm pedicle to the sacral por- tion of the spinal canal, passing through the aforementioned cystic mass (Figure 2, Video). On Doppler examination, there was a low-velocity flow signal within the proximal part of the Additional Supporting Information may be found in the online version of this article. Correspondence to: A. Corbacioglu Esmer V C 2016 Wiley Periodicals, Inc. VOL. 00, NO. 00, MONTH 2016 1