Prenatal MRI Diagnosis and Favorable Neurodevelopmental Outcome in Isolated Medullary Tegmental Cap Dysplasia: A Case Report and Literature Review

Medullary tegmental cap dysplasia (MTCD) is an extremely rare congenital brainstem malformation, with few cases reported to date. We report a fetus referred for an occipital meningocele, in whom fetal MRI at 27 weeks’ gestation identified a dorsal protrusion of the medulla oblongata consistent with MTCD. No supratentorial, infratentorial, or extracerebral anomalies were detected. Prenatal investigations, including chromosomal microarray and trio whole-exome sequencing, were noncontributory. Postnatal magnetic resonance imaging confirmed isolated MTCD with an occipital meningocele and preserved transverse pontine fibers on diffusion tractography. Neonatal evaluation was unremarkable apart from transient feeding difficulties and obstructive sleep apnea in the context of RSV infection. At 16 months, the child showed normal neurodevelopment, including independent walking, language, and social interaction. This case expands the phenotypic spectrum of MTCD and suggests a favorable outcome when MTCD is isolated and genetic investigations are negative. Recognition on fetal imaging is essential for prenatal counseling and postnatal management.