EP07.01: Fetal thymic teratoma: maturation marvel

Teratomas, in the thymus of fetuses, present challenges in diagnosis and management. We report a 27 yr old primigravida who came for fetal ultrasound at 19 weeks and 5 days of gestation. Ultrasound showed smooth thin walled anechoic lesion measuring 2.2 x1.5x1.4 cm seen in the thorax posterior to sternum and superoanterior to great vessels and heart (see figure 1). No solid component or calcification seen. No superior extension of mass seen into the neck. No vascularity demonstrable on Doppler. Structurally heart appeared normal. However mild deviation of the cardiac axis seen to left. No pleural or pericardial effusion seen. Power and colour Doppler showed internal mammary arteries on either side of the mass suggesting its origin from the thymus (see figure 2). A diagnosis of thymic cyst or cystic lymphangioma of thymus was considered. Serial ultrasound examinations were scheduled every three weeks to monitor the size of the lesion. The size increased in follow up scans and MRI done showed the same findings as seen on ultrasound with mild compression observed over the heart and great vessels. However the heart appeared structurally normal. Throughout the follow-up period, the fetus continued to demonstrate appropriate growth. The baby was born full-term LSCS uneventfully with a birthweight was 3.6kg.Postnatally the baby was taken up for surgery due to increase in size of the cyst measuring 9.0 x4.1 cm. Baby was successfully managed by surgical excision. On Histopathology the lesion was diagnosed as mature teratoma of thymus (see figure 3). Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.