(Case courtesy: Sapthagiri digital imaging center, Bangalore)

Aqueductal stenosis. CSF flow study could have proven beneficial.

What observation apart from hydrocephalus favour aqueductal stenosis? 

Flow void across aqueduct on T2 sagittal images, and upward bowing of corpus callosum. Detailed evaluation (not included) showed a dysgenetic corpus callosum, with markedly deficient body of corpus callosum.

Considering a congenital cause, what other morphological finding could have been seen?

Aqueductal web/diaphragm is sometimes seen. I feel there is a thin aqueductal web, even in this case.

Treatment of aqueductal stenosis:
Third ventriculostomy +/- VP shunting.