OP05.09: Prenatal diagnosis of middle ear hypoplasia in 2 cases of Treacher Collins syndrome and OAV spectrum using magnetic resonance imaging

We report two cases of Treacher Collins syndrome and Goldenhar syndrome (oculo-auriculo-vertebral spectrum) with prenatal identification of middle ear hypoplasia at respectively 27 and 36 weeks gestation, using magnetic resonance imaging (MRI). The fetus with Treacher Collins syndrome presented with retrognathism, bilateral external ear deformity and mandibular hypoplasia. The fetus with OAV spectrum showed retrognathism and left low-set and deformed ear. In both cases, MRI made it possible to depict marked hypoplasia of the tympanic cavity, which was bilateral in the first fetus and unilateral in the second one. Those two syndromes are characterized by craniofacial abnormalities including middle ear hypoplasia, which cannot be diagnosed using ultrasound imaging. Middle ear cavity is beautifully depicted by MRI in normal fetuses. We emphasize here the use of this imaging modality in diagnosing middle ear hypoplasia, which has never been reported so far. The complementary role of computed tomography will be discussed.