Proboscis lateralis with associated orbital cyst: detailed MR and CT imaging and correlative embryopathy.

Proboscis lateralis is a rare craniofacial malformation. We present a case in a 1-week-old male infant, describe the clinical and imaging findings, and discuss the pertinent embryology. MR and CT proved to be complementary: CT provided anatomic detail in bone, defined the nasal cavity, and aided in determining the relationship of the proboscis and orbit; MR clarified the relationship of the proboscis to the orbit and skull base, and the relationships of normal brain to the dysplastic ethmoid centers.