Journal List > J Korean Soc Radiol > v.67(3) > 1087159

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Kim, Yoon, Cho, Hwang, Kim, Hwang, and Yoon: Sacrococcygeal Fetus-in-Fetu Mimicking a Teratoma: A Rare Case with Brain Tissue and an Immature Teratoma Component
Case Report
Pediatric Radiology
Journal of the Korean Society of Radiology

Journal of the Korean Society of Radiology 2012; 67(3): 205-208.

Published online: 7 September 2012

DOI: https://doi.org/10.0000/jksr.2012.67.3.205

Sacrococcygeal Fetus-in-Fetu Mimicking a Teratoma: A Rare Case with Brain Tissue and an Immature Teratoma Component

Cherry Kim, MD1, Hye-Kyung Yoon, MD1, Young Ah Cho, MD1, Jae-Yeon Hwang, MD1, Ai-Rhan Kim, MD2, Hee Sang Hwang, MD3, Chong Hyun Yoon, MD1

1Department of Radiology and Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.

2Department of Neonatology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.

3Department of Pathology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.

Corresponding author: Chong Hyun Yoon, MD. Department of Radiology and Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, 88 Olympic-ro 43-gil, Songpa-gu, Seoul 138-736, Korea. Tel. 82-2-3010-4362, Fax. 82-2-476-0090, chyoon@amc.seoul.kr

Received 14 February 2012       Accepted 3 July 2012

Copyright © 2012 The Korean Society of Radiology

Abstract

Fetus in fetu is a rare, nonviable, malformed parasitic twin, which grows within the body of its partner. It has been known as being almost always anencephalic and rarely reported to have an immature teratoma component. We report a case of a sacrococcygeal fetus-in-fetu with brain tissue seen on both imaging studies and pathologic specimens, containing an immature teratoma component on pathologic examinations. Imaging studies including plain radiography were very helpful for the correct diagnosis.

Keywords: Fetus in Fetu, Teratoma, Infants, Newborn, Ultrasound, MRI

Figures and Tables

Fig. 1
A sacrococcygeal fetus in fetu in a newborn baby girl.
A. Abdominal radiograph shows a large buttock mass containing multiple amorphous calcifications. There are at least two long bones (thin white arrows), vertebral bodies (black arrows), and phalanges-like bones (thick white arrows).
B. Specimen radiograph of the excised mass reveals long bones representing the femur, tibia and fibula, short tubular bones representing the feet and hands, and a rounded ilium-like bone. The long bone was accidentally broken during manipulation of the mass.
C. The postnatal ultrasonogram shows small contiguous hypoechoic structures with a focal calcification (arrow), which looks like an underdeveloped vertebral column.
D. There are convoluted band-like structures representing the brain cortices with cystic areas, using a high resolution linear probe.
E. The T1 weighted gadolinium enhanced coronal image shows convoluted band-like structures with cystic areas in the buttock mass. It seems like brain tissue and a venticle.
F. Photographs of the gross specimen. There is a large, round head-like structure with two feet (arrows) on the other end. Feet are well developed and covered with skin.
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