MEGA CISTERNA MAGNA

Course overview

MEGA CISTERNA MAGNA REFERS TO A CYSTIC POSTERIOR FOSSA MALFORMATION THAT IS CHARACTERIZED BY AN ENLARGED CISTERNA MAGNA, ABSENCE OF HYDROCEPHALUS, AND AN INTACT CEREBELLAR VERMIS. IT MUST BE DIFFERENTIATED FROM PERSISTENT BLAKE’S POUCH CYST, POSTERIOR FOSSA CYSTS, DANDY-WALKER VARIANT, AND POSTERIOR FOSSA NEOPLASIA. THE MEGA CISTERNA MAGNA IS HYPOTHESIZED TO DEVELOP EMBRYOLOGICALLY FROM THE PERMEABILIZATION OF BLAKE’S POUCH. MEGA CISTERNA MAGNA IS TYPICALLY AN INCIDENTAL RADIOGRAPHIC FINDING BUT MAY BE ASSOCIATED WITH CERTAIN PSYCHIATRIC CONDITIONS, AND IN SMALLER STUDIES, PATIENTS HAVE PERFORMED INFERIORLY ON SPECIFIC COGNITIVE FUNCTIONING, INCLUDING MEMORY, EXECUTIVE FUNCTIONING, AND VERBAL FLUENCY. THERE IS NO SPECIFIC TREATMENT OR NECESSARY SURGICAL INTERVENTION FOR PATIENTS WITH INCIDENTALLY DISCOVERED MEGA CISTERNA MAGNA. THIS REVIEW ARTICLE SUMMARIZES THE EMBRYOLOGY AND RELEVANT ANATOMY AND DESCRIBES THE RADIOGRAPHIC APPEARANCE OF THE MEGA CISTERNA MAGNA AND HOW IT CAN BE DIFFERENTIATED FROM SIMILAR DIAGNOSES; IT PROVIDES A FRAMEWORK FOR MEMBERS OF THE INTERPROFESSIONAL TEAM.