Bilateral cystic coloboma with microphtalmos and eyelid agenesis: US and MRI findings.

INTRODUCTION: The combination of bilateral microphthalmos, cystic coloboma and eyelid agenesis is rare. The definite diagnosis of this malformation is established by fundoscopic examination and confirmed by imaging modalities such as ultrasonography (US) and magnetic resonance imaging (MRI). This disorder may be associated with specific chromosomal abnormalities.

CASE REPORT: A 1-week-old male newborn was referred for bilateral eyelid agenesis. He was born at term by caesarean for foetal distress, after an uneventful gestation. The Apgar score was 8/9/9, birth weight 3420 grams and cranial perimeter 34cm. Ultrasound (US) follow-up of the pregnancy was unremarkable. His parents were second degree consanguineous. At birth, physical examination of both eyes showed the absence of the palpebral fissure on both eyes with a continued skin covering the globes. There was no facial dysmorphism and no other abnormal finding on the physical examination.

RESULTS: Right after birth, transfontanellar US showed a normal brain US of the orbits disclosed the abnormal ocular globes, appearing as bilobar cysts separated by a hyperechoic membrane, bilaterally. Posterior to the cysts, a hyperechoic structure was described as hypoplastic optic nerves. On the basis of US findings, the diagnosis of bilateral colobomateous cysts was suggested. Brain magnetic resonance imaging (MRI) confirmed the diagnosis, showing bilobar cystic deformation of the eyeballs. Bilateral microphtalmos was described, because of the shortening of the anteroposterior diameter on the axial plane (11mm on the right and 13mm on the left: the normal mean value being 21,00mm). No brain abnormality was found. Genetic analyses disclosed abnormalities on chromosomes 9q31.2, 18p11.32 and 22q11.21.

CONCLUSION: This report has allowed us to review the diagnostic criteria of coloboma, the related imaging features and genetic findings, in a complex setting of associated microphtalmos and eyelids agenesis.