Prenatal diagnosis of an adrenal mature teratoma mimicking a neuroblastoma

Aim of the study: To present our experience with an adrenal antenatal mass firstly diagnosed as a left adrenal neuroblastoma that turned out to be a mature teratoma after anatomopathology. Case description: We present the case of an infant with an antenatal diagnosis of a left adrenal cystic image on the 22nd week of amenorrhea ultrasound. The fetal MRI showed a 20 x 13 mm non-calcified cystic formation of the left adrenal gland, compatible with a neuroblastoma.At birth, the diagnosis has been confirmed by an ultrasound that showed an anechogenic image of the left adrenal gland of 17 x 12 mm, with thin walls.Besides, in the 9 months interval between birth and the last CT scan, the image had minimally diminished in size. Then it stabilized at about 2 cm. The workup was otherwise normal. The infant was closely monitored during his first year and in the absence of significant regression of the adrenal mass, we decided to perform a left laparoscopical adrenalectomy. Unexpectedly, the anatomopathologist results showed a mature cystic adrenal teratoma. Conclusions: An adrenal mass diagnosed antenatally is generally a haemorrhage or a neuroblastoma. Only two other case of unexpected adrenal teratoma in infants are described in literature. Adrenal teratomas are very rare and those diagnosed antenatally even more. At present, we have no clinical, biological, or radiological evidence to suspect them before surgical removal.