Segmental Agenesis of the Corpus Callosum With Pituitary Hypoplasia

Abstract

We report a 3-year-old male with findings of segmental agenesis of the corpus callosum, pituitary hypoplasia, and Chiari I malformation. The patient was born at 33 weeks and spent five weeks in the NICU for hypoglycemia, hypotension, and dyspnea. In infancy, the patient passed an adrenocorticotropic hormone stimulation test, while cortisol, growth hormone, and insulin-like growth factor levels were within reference range. Following height and weight percentile regression the patient underwent arginine and clonidine stimulation testing at 3 years of age, prompting pituitary evaluation via MRI. The results provided exemplary neuroimaging of segmental callosal agenesis, in which the genu and splenium form despite the absence of the callosal body. This finding adds support to a newer theory of embryological callosal development where progression does not occur linearly in the rosto-caudal direction.

Keywords: agenesis of the corpus callosum; congenital hypopituitarism; corpus callosum; hyposomatotropism; midline defect; septo-optic dysplasia.

Figure 1. Segmental agenesis of the corpus callosum and pituitary hypoplasia

A) Sagittal T1-weighted image (T1WI) shows an intact rostrum, intact genu, absent callosal body, intact isthmus, and intact splenium. Note the small pituitary volume (6.2 x 1.5 x 6.7mm), with a lack of normal T1WI hyperintensity of the neurohypophysis.  B) Coronal T1WI confirms absent commissural fibers bridging the midline.

Figure 2. Infundibulum and pituitary hypoplasia on coronal T1 MRI

A) Anterior to the callosal body agenesis, T1-weighted image (T1WI) appreciates the presence of commissural genu fibers, and B) a thin infundibulum and hypoplastic pituitary gland.