Partial agenesis of the corpus callosum (PACC) is a rare brain birth defect characterized by incomplete development of the corpus callosum, the primary white matter bundle that connects the right and left hemispheres. PACC can be associated with other congenital abnormalities, including malformation of the brain’s ventricular system, such as colpocephaly or ventriculomegaly, and it is typically considered a pediatric diagnosis. Clinically, this condition may present with a broad continuum of cognitive and socioemotional difficulties ranging from significant day-to-day impairment to relative independence. Newly diagnosed PACC with ventriculomegaly in adults is very rare (0.0200.025%) and little is known about neuropsychological functioning in adults with this condition. The aim of this case study is to add to the literature base for better PACC neuropsychological conceptualization.

This case study involves neuropsychological evaluation of cognitive and behavioral health functioning of a 37-year-old active duty service member (ADSM) with recently identified PACC and ventriculomegaly (via incidental imaging finding). The ADSM reported a history of learning difficulty, though she was able to earn rank of sergeant first class in a low density military occupation specialty (i.e., Mortuary Affairs) over an 18.5 year active duty career.

Cognitive testing was notable for consistently low to exceptionally low attention and processing speed scores. Mild executive dysfunction was also noted in the areas of planning and inhibition. Emotionally, she endorsed mild somatic and depression symptoms. Interpersonally, she was shy and avoidant with longstanding characterological traits characterized by worry, insecurity, and general tendency to catastrophize.

This case adds to the broad clinical presentation of PACC with ventriculomegaly, and highlights that even in the context of a significant congenital brain deformity and longstanding cognitive deficits, independent functioning can be achieved.