Meckel-Gruber syndrome: pathologic manifestations, minimal diagnostic criteria, and differential diagnosis.

This article provides an overview of the major pathologic manifestations of Meckel-Gruber syndrome, current knowledge about its pathogenesis, minimal diagnostic criteria, and differential diagnosis. Typical sonographic findings (occipital encephalocele, postaxial polydactyly, and cystic enlargement of the kidneys) allow for diagnosis of most cases before the 14th week of gestation, but the pathologist may encounter clinically unsuspected or atypical cases that require morphologic confirmation. In these cases, a meticulous autopsy is necessary to establish the diagnosis of Meckel-Gruber syndrome.