Answer to the case of the week #243

Andrea L. Gonzales, RDMS; Luis A. Izquierdo-Encarnacion, MD, RDMS, RDCS; Samantha Long.

Regional Obstetric Consultants, 836 Prudential Drive, Suite 1800, Jacksonville, FL 32207, USA.

 

Case report

A 30 year old gravida 6, para 1, was referred to our clinic for consultation at 11 3/7 weeks gestation for a history of four spontaneous abortions and compound heterozygous state for methylenetetrahydrofolate reductase (MTHFR). There were no other known medical problems. Following the initial consultation, the patient was evaluated in our office every four weeks to monitor fetal anatomy, growth and development. Sonographically unremarkable examinations were performed every four weeks from 11 3/7 weeks of gestation to 30 4/7 weeks.

At 34 4/7 weeks, the patient was found to have polyhydramnios (AFI 30.7 cm). Additionally, the fetus was noted to have a solid, homogeneous, hypervascular neck mass anterior to the trachea, measuring 5.1 x 4.8 x 4.7 cm. This mass was symmetrically bi-lobed and slightly hypoechoic. The neck of the fetus was initially hyperextended, but did move into a neutral position by the end of the examination. During real-time examination, the fetus was observed swallowing and the stomach bubble was identified. The trachea could be identified and appeared patent from the mouth, down the neck and past the neck mass.

Following this examination, the patient"s blood was drawn and sent for thyroglobulin antibodies, thyroid peroxidase antibodies, TSH and Free T4. All labs returned within normal limits. Fetal MRI was attempted, but adequate images could not be obtained due to fetal lie and fetal motion.

Due to the late gestational age, fetal sampling for thyroid status was not performed. Therefore, no fetal therapy was undertaken. The patient was monitored with twice-weekly fetal testing for 2 6/7 weeks. At 37 1/7 weeks and 37 2/7 weeks of gestation the patient was administered Celestone to enhance fetal lung maturity. At 37 3/7 weeks the patient delivered a female weighing 3334 g via repeat cesarean section. As a precaution, the pediatric ENT team was present and prepared for intubation. Apgar scores of 8 and 9 were recorded and no intubation was necessary.

On physical exam of the newborn there was a bulge noted at the anterior surface of the neck. The neck was able to achieve neutral position. Neonatal sonography revealed a soft tissue mass nearly identical to the prenatal sonographic findings. The neonate"s TSH was 472. The neonate was diagnosed with congenital hypothyroidism and goiter, started on Synthroid 50 mcg and discharged home on day of life 4. As of this writing, no additional follow-up is available.

Images 1, 2: The images show prenatal ultrasonographic appearance of the fetal goiter (green arrow on the image 1). The image 2 represents a color Doppler scan of the fetal neck with the goiter. The mass of the goiter shows hyper-vascularization.

 

Images 3, 4: The image 3 shows 3D representation of the fetal neck with the go iter (arrow). The image 4 represents a fusion of the image 3 with a drawing explaining the position of the fetal head, neck, and localization of the mass of the goiter (arrow).

 

Images 5, 6, 7, and 8: Postnatal sonographic appearance of the fetal goiter.

 

 

Video 1: The video shows prenatal ultrasonographic scan of the fetal neck with a slightly hypoechoic bilobate mass representing the fetal goiter.

 

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