Clinicoradiological aspects of pontine tegmental cap dysplasia: Case report of a rare hindbrain malformation

Abstract

Malformations involving the brainstem are very rare and present with a varied spectrum of clinical symptoms due to multiple cranial nerve palsies and pyramidal tract involvement. Of these, pontine tegmental cap dysplasia is a very unusual malformation, characterized by ventral pons hypoplasia and an ectopic dorsal band of tissue, projecting into the fourth ventricle, from dorsal pontine tegmentum. A 4-year-old male child, presenting with left facial nerve palsy, revealed hypoplastic ventral pons and an ectopic structure on magnetic resonance imaging (MRI). The ectopic structure was isointense to pons, arose from the left side of dorsal pontine tegmentum, at pontomedullary junction and protruded into the fourth ventricle, impinging upon the left seventh and eighth cranial nerves. Diffusion tensor imaging (DTI) depicted abnormal white matter tracts in ectopic tissue with absent transverse pontine fibres and abnormal middle and superior cerebellar peduncles. The typical MRI appearance, coupled with DTI, helped us reach an accurate diagnosis of pontine tegmental cap dysplasia, in a setting of neurological dysfunction.

Keywords

Brainstem malformations - cranial nerve palsies - hindbrain malformations - pontine tegmental cap dysplasia

Publikationsverlauf

Artikel online veröffentlicht:
26. Juli 2021

• References

• 1 Jissendi-Tchofo P, Doherty D, McGillivray G, Hevner R, Shaw D, Ishak G. et al. Pontine Tegmental Cap Dysplasia: MR Imaging and Diffusion Tensor Imaging Features of Impaired Axonal Navigation. Am J Neuroradiol 2009; 30: 113-9
• 2 Barth PG, Majoie CB, Caan MW, Marian A, Weterman J, Kyllerman M. et al. Pontine tegmental cap dysplasia: Anovel brain malformation with a defect in axonal guidance. Brain 2007; 130: 2258-66
• 3 Stankiewicz P, Lupski JR. Genome architecture, rearrangements and genomic disorders. Trends Genet 2002; 18: 74-82
• 4 Maeoka Y, Yamamoto T, Ohtani K, Takeshita K. Pontine hypoplasia in a child with sensorineural deafness. Brain Dev 1997; 19: 436-9
• 5 Ouanounou S, Saigal G, Birchansky S. Möbius syndrome. AJNR Am J Neuroradiol 2005; 26: 430-2
• 6 Harding B, Vossough A, Goldberg E, Santi M. Pontine tegmental cap dysplasia: Neuropathological confirmation of a rare clinical/radiological syndrome. Neuropathol Appl Neurobiol 2016; 42: 301-6
• 7 Singh D, Hsu CC, Kwan GN, Korah I. Pontine Tegmental Cap Dysplasia: MR Evaluation of Vestibulocochlear Neuropathy. J Neuroimaging 2015; 25: 1038-43
• 8 Nixon JN, Dempsey JC, Doherty D, Ishak GE. Temporal bone and cranial nerve findings in pontine tegmental cap dysplasia. Neuroradiol 2016; 58: 179-87
• 9 Doherty D, Millen KJ, Barkovich AJ. Midbrain and hindbrain malformation: Advances in clinical diagnosis, imaging, and genetics. Lancet Neurol 2013; 12: 381-93