Pontine Tegmental Cap Dysplasia Research Articles

Clinical and Radiological Findings in Children with Anomalous Pontine Cranial Nerves.

We retrospectively reviewed the clinical and radiologic findings in 17 children with an aberrant cisternal CN7 and found that these patients had additional anomalies involving other pontine cranial nerves. The hallmark imaging feature identified in all patients was aberrant cisternal segment of an enlarged appearing CN7. The abnormal nerve coursed anteriorly towards the Gasserian ganglion where it fanned out towards the internal auditory canal, Meckel's cave or both. This finding was accompanied by a small cisternal CN5 which often had a lateral bowed appearance. CN5 and CN7 were abnormally close to each other. Meckel's cave appeared widened posteriorly and often was close to or merged with the internal auditory canal. Other abnormalities in the pontine cranial nerves included CN8 deficiency in the majority of children and variable CN6 deficiency. This constellation of findings was most often discovered in children having MR evaluation for sensorineural hearing loss and the majority of patients had preserved facial nerve function. In patients with available genetic testing, no pathogenic variants were observed. Interestingly, in 13 children with available birth history, 9 were notable for maternal or gestational diabetes (69%), suggesting a possible early intrauterine insult to the developing nerves.ABBREVIATIONS: CN= cranial nerve; OAVS= Oculo-Auriculo-Vertebral Spectrum; IAC= Internal Auditory Canal; PTCD= Pontine Tegmental Cap Dysplasia; EMR= Electronic Medical Record; SNHL= sensorineural hearing loss.

Ocular Findings in Pontine Tegmental Cap Dysplasia.

To describe the ocular complications experienced by patients with pontine tegmental cap dysplasia (PTCD) and the management strategies used to care for these children. Subjects with PTCD were recruited through social media advertisement and completed a survey gathering information on potential ocular problems related to the patient's PTCD disease and any current or previous treatments. Twenty-two patients or guardians completed the survey. Neurotrophic cornea was the most common ocular diagnosis (82%), followed by facial palsy (59%), dry eye syndrome (59%), and blepharitis (55%). Other diagnoses included cortical visual impairment (27%), strabismus (27%), amblyopia (18%), and nystagmus (18%). Common treatment modalities included lubricating eye drops (59%) or ointment (50%), contact lenses (14%), punctal plugs (27%), glasses (45%), and patching (18%). The most common surgical interventions were temporary or permanent tarsorrhaphy (64%) and amniotic membrane grafts (23%). In total, 68% of families reported self-injury to eyes and 91% reported the child to be primarily a visual learner. PTCD is a newly described, very rare disorder with a variety of vision-threatening ocular manifestations. It is essential that the ophthalmologist be aware of the potential for neurotrophic cornea because timely treatment could prevent corneal scarring, perforation, and blindness.

Maternal Serum Eye Drops in the Management of Pediatric Persistent Corneal Epithelial Defects: A Case Series.

We report our experience with the use of maternally derived serum eye drops as adjunctive treatment in the management of pediatric persistent corneal epithelial defects. Five eyes of 4 patients were identified in a retrospective review of pediatric patients with persistent corneal epithelial defects who received maternal serum drops. Diagnoses associated with the defects comprised pontine tegmental cap dysplasia with bilateral cranial nerve V1, V2, V3, and VII palsies; pontine tegmental cap dysplasia with left cranial nerve V1, VII, and VIII palsies; traumatic left cranial nerve II, V1, V2, and VI palsies due to a basilar skull fracture; and Stevens-Johnson syndrome with ocular involvement. We evaluated the feasibility of using maternally derived serum drops; thus, we looked at the ability to prepare and tolerate the drops as well as any complications that could have been associated with treatment. Other data collected included visual acuity, corneal examination, and current and previous treatments. Both the duration of therapy and time of follow-up ranged from 5 to 28 months. All patients experienced improvement or resolution of their corneal epithelial defects within 3 weeks of initiating serum eye drops. Furthermore, there were no adverse effects from the use of allogeneic serum drops. Maternal serum eye drops are a well-tolerated and potentially beneficial addition to the management of pediatric persistent corneal epithelial defects.

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

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.

Pontine Tegmental Cap Dysplasia and Challenges in Facial Reconstructive Surgery.

Pontine tegmental cap dysplasia (PTCD) is a rare condition that affects the brain stem and multiple cranial nerves, which can result in bilateral facial palsies, hearing loss, bilateral trigeminal nerve dysfunction, oculomotor apraxia, feeding difficulties, seizures, hypotonia, and undeveloped speech. We document a case in which a patient with PTCD presents with a challenging lip deformity and requires multidisciplinary treatment to improve reconstructive surgical success and treatment outcomes. An extensive literature review was conducted. This report serves to increase awareness of PTCD and the need for multidisciplinary teams to participate in reconstruction of facial defects in a complex medical setting.

Dental Intervention to Promote Lip Repair in a Patient with Pontine Tegmental Cap Dysplasia: A Multidisciplinary Approach

Dental Intervention to Promote Lip Repair in a Patient with Pontine Tegmental Cap Dysplasia: A Multidisciplinary Approach

Pontine tegmental cap dysplasia accompanied by a duplicated internal auditory canal.

Pontine tegmental cap dysplasia accompanied by a duplicated internal auditory canal.

Dental Intervention to Promote Lip Repair in a Patient with Pontine Tegmental Cap Dysplasia: A Multidisciplinary Approach

Dental Intervention to Promote Lip Repair in a Patient with Pontine Tegmental Cap Dysplasia: A Multidisciplinary Approach

Magnetic Resonance Imaging of Malformations of Midbrain-Hindbrain.

We aim to review the magnetic resonance imaging appearance of malformations of midbrain and hindbrain. These can be classified as predominantly cerebellar malformations, combined cerebellar and brain stem malformations, and predominantly brain stem malformations. The diagnostic criteria for the majority of these morphological malformations are based on neuroimaging findings. The predominantly cerebellar malformations include predominantly vermian hypoplasia seen in Dandy-Walker malformation and rhombencephalosynapsis, global cerebellar hypoplasia reported in lissencephaly and microlissencephaly, and unilateral cerebellar hypoplasia seen in PHACES, vanishing cerebellum, and cerebellar cleft. Cerebellar dysplasias are seen in Chudley-McCullough syndrome, associated with LAMA1 mutations and GPR56 mutations; Lhermitte-Duclos disease; and focal cerebellar dysplasias. Cerebellar hyperplasias are seen in megalencephaly-related syndromes and hemimegalencephaly with ipsilateral cerebellomegaly. Cerebellar and brain stem malformations include tubulinopathies, Joubert syndrome, cobblestone malformations, pontocerebellar hypoplasias, and congenital disorders of glycosylation type Ia. Predominantly brain stem malformations include congenital innervation dysgenesis syndrome, pontine tegmental cap dysplasia, diencephalic-mesencephalic junction dysplasia, disconnection syndrome, and pontine clefts.

Temporal bone and cranial nerve findings in pontine tegmental cap dysplasia.

Pontine tegmental cap dysplasia (PTCD) is a recently described brain malformation associated with multiple cranial neuropathies, most commonly congenital sensorineural hearing loss. The purpose of this study is to systematically characterize the cranial nerve and temporal bone findings in a cohort of children with this rare condition. Sixteen patients with PTCD and diagnostic quality imaging were retrospectively reviewed. All patients had high-resolution MR of the brain and/or internal auditory canals, and seven patients had additional high-resolution CT of the temporal bones. Studies were evaluated by two pediatric neuroradiologists for cranial nerve and temporal bone anomalies. Fifteen of 16 patients (94%) had duplication of one or both internal auditory canals. Of the 24 total duplicated internal auditory canals, all 24 (100%) demonstrated stenosis or atresia of the vestibulocochlear nerve canal, as well as ipsilateral vestibulocochlear nerve aplasia. Of the non-duplicated internal auditory canals, 63% (5/8) were atretic or stenotic. Thirty-eight percent (3/8) were associated with absent vestibulocochlear nerve, and 38% (3/8) demonstrated isolated cochlear nerve aplasia. Twenty-five percent (2/8) demonstrated normal vestibulocochlear nerves, both in the same patient. Fifteen of 16 patients overall (94%) demonstrated bilateral cochlear nerve aplasia. Of the 32 total temporal bones, 4 (13%) demonstrated facial nerve aplasia. Seventy-nine percent (22/28) of facial nerves that were present demonstrated an aberrant origin or course. Patients with PTCD have highly characteristic temporal bone and cranial nerve findings on both CT and MR. Recognition of these findings is important for improved diagnosis of this rare disorder, particularly by CT.

Pontine Tegmental Cap Dysplasia in an Extremely Low Birth Weight Preterm Infant

Case Study: Pontine tegmental cap dysplasia (PTCD) is a rare hindbrain and cranial nerve malformation syndrome characterized by distinct imaging findings. The latter includes pontine hypoplasia with ventral flattening and a dorsal “tegmental cap,” that is, a thorn-like tissue protrusion into the fourth ventricle. So far, only 27 sporadic cases have been described. Here, we provide an overview of the phenotype and report the first extremely low birth weight preterm infant with PTCD as the severe end of the disease spectrum. We highlight an agonizingly painful blepharospasm suggestive of trigeminal and possibly facial nerve impairment as a new feature in PTCD and illustrate prenatal cranial imaging findings suggestive of the disease. As the underlying genetic cause of PTCD remains unknown, we performed chromosome analysis, array CGH and whole-exome sequencing. We present the corresponding results and discuss potential candidate genes/regions. Our report can likely promote the diagnosis of PTCD in further patients and support the identification of the underlying genetic cause.

Pontine tegmental cap dysplasia: Report of two new cases from Kuwait

We describe two patients (a Filipino boy aged 2.7 years and a Kuwaiti girl aged 4.8 Years) with clinical and MRI findings consistent with the diagnosis of pontine tegmental cap dysplasia (PTCD) and compare them with 23 other cases reported in the literature. Both presented with feeding problems (VII nerve), sensori-neural deafness (VIII nerve) and hypotonia from birth and later developed corneal opacities due to loss of corneal sensation (V nerve). They have severe psychomotor developmental delay. The MRI of their brain showed a flattened ventral pons, vaulted “cap”- like structure protruding into 4th ventricle and a “molar tooth” sign. One of our patients also had Tetralogy of Fallot (TOF) successfully corrected. The other had no extracranial manifestations. The findings in our patients are similar to those reported except for the occurrence of TOF which has not been reported before in association with PTCD.

Partitioned Versus Duplicated Internal Auditory Canal

A double internal auditory canal (IAC) is an uncommon malformation among temporal bone anomalies related to sensorineural hearing loss. This anomaly has been described as an isolated finding in otherwise normal patients, as well as a frequent feature in pontine tegmental cap dysplasia (PTCD). In both circumstances, the term duplication is currently used to describe this malformation. We conducted a retrospective study on 3 cases of IAC duplication (2 isolated and 1 PTCD-associated form) and reviewed the literature to evaluate both imaging features and differences between the 2 forms. All 3 patients underwent high-resolution computed tomography and magnetic resonance imaging. Neuroimaging documented different radiologic features between isolated and PTCD-associated IAC duplication. In the isolated form, the IAC seemed to have normal position and size, but it was partitioned in 2 portions by a complete or incomplete bony septum. Conversely, in the PTCD-associated form, neuroimaging revealed the presence of 2 separated and anomalously coursing canals for the facial and vestibulocochlear nerve. The aforementioned different radiologic findings probably reflect a more complex spectrum of etiopathogenetic mechanisms affecting the facioacoustic primordium and leading to overlapping anomalies of the IAC. We speculate on the appropriate terminology in describing this entity and propose that "partition" should be used to describe a double IAC otherwise normal in size and location; conversely, "duplication" should be reserved for IAC anomalies encountered in patients with PTCD or other hindbrain malformations.

Cerebellar hypoplasia: Differential diagnosis and diagnostic approach

Cerebellar hypoplasia (CH) refers to a cerebellum with a reduced volume, and is a common, but non-specific neuroimaging finding. The etiological spectrum of CH is wide and includes both primary (malformative) and secondary (disruptive) conditions. Primary conditions include chromosomal aberrations (e.g., trisomy 13 and 18), metabolic disorders (e.g., molybdenum cofactor deficiency, Smith-Lemli-Opitz syndrome, and adenylosuccinase deficiency), genetic syndromes (e.g., Ritscher-Schinzel, Joubert, and CHARGE syndromes), and brain malformations (primary posterior fossa malformations e.g., Dandy-Walker malformation, pontine tegmental cap dysplasia and rhombencephalosynapsis, or global brain malformations such as tubulinopathies and α-dystroglycanopathies). Secondary (disruptive) conditions include prenatal infections (e.g., cytomegalovirus), exposure to teratogens, and extreme prematurity. The distinction between malformations and disruptions is important for pathogenesis and genetic counseling. Neuroimaging provides key information to categorize CH based on the pattern of involvement: unilateral CH, CH with mainly vermis involvement, global CH with involvement of both vermis and hemispheres, and pontocerebellar hypoplasia. The category of CH, associated neuroimaging findings and clinical features may suggest a specific disorder or help plan further investigations and interpret their results. Over the past decade, advances in neuroimaging and genetic testing have greatly improved clinical diagnosis, diagnostic testing, recurrence risk counseling, and information about prognosis for patients and their families. In the next decade, these advances will be translated into deeper understanding of these disorders and more specific treatments.

A case of pontine tegmental cap dysplasia with comorbidity of oculoauriculovertebral spectrum

Pontine tegmental cap dysplasia (PTCD) is a newly described brainstem malformation with distinct neuroimaging findings, characterized by a flattened ventral pons, cerebellar vermal hypoplasia and vaulted pontine tegmentum that forms a "caplike" or "beaklike" bulge projecting into the fourth ventricle. We describe a 3-month-old infant male who presented with typical neuroradiological findings as well as clinical features of PTCD. Notably, he manifested multiple anomalies with left ocular and facial hypoplasia, bilateral sensorineural hearing loss and rib and vertebral anomalies. Oculoauriculovertebral spectrum (OAVS) was thus considered to be an accompanying phenotype of this patient. The unique comorbidity seen in this patient suggests that PTCD and OAVS may partly share a common mechanism in their pathogenesis.

Ectopic peripontine arcuate fibres, a novel finding in pontine tegmental cap dysplasia

BackgroundPontine Tegmental Cap Dysplasia (PTCD) is a recently described hindbrain malformation presenting hypoplasia of the ventral pons, and a “pontine tegmental cap”. Previous DTI studies identified ectopic transversely oriented nerve fibres in the cap, and absence of transverse fibre bundles in the ventral pons, characterizing PTCD as an embryonic axon guidance defect. A new case with relatively mild symptoms was investigated to identify fibre tracts in the tegmental cap by tracking their connections. In the process a new bilateral ectopic fibre tract was found. MethodsRoutine T1- and T2 weighted images and Diffusion Tensor Imaging (DTI) data were obtained on a 3 T MR scanner. Fractional Anisotropy maps colour coded for orientation were generated. High Angular Resolution Diffusion Imaging (HARDI) data were used for reconstructing maps denoting multiple fibre orientations (i.e. fibre crossings) per voxel through which accurate fibre tracking was performed. Results1.A pontine tegmental cap was discovered on routine MRI and shown to carry transverse oriented fibres on DTI as in previously reported cases of PTCD.2.A new finding revealed by DTI with colour coding and fibre tracking, was a robust midline bundle, traced back to the lower brainstem, that ended rostrally in two semi-arcuate loops skirting the outer margins of the pons, to connect to the cerebellar hemispheres close to but outside the middle cerebellar peduncles. Part of this fibre tract was detectable on routine MRI. InterpretationPeripontine arcuate fibres were identified, representing a second structural abnormality not previously recorded in PTCD.

Ectopic peripontine arcuate fibers, a novel finding in pontine tegmental cap dysplasia

Ectopic peripontine arcuate fibers, a novel finding in pontine tegmental cap dysplasia

Abnormalities of the Cochlear Nerves and Internal Auditory Canals in Pontine Tegmental Cap Dysplasia

Abnormalities of the Cochlear Nerves and Internal Auditory Canals in Pontine Tegmental Cap Dysplasia

Cerebellar disorders in children

This is a comprehensive reference book covering the topic of cerebellar disorders in children. Appropriately, it starts with a review of the development of the cerebellum, and what is known of molecules that control key events in cerebellar neurogenesis, migration, and dendrite development. This is followed by sections dealing with functional anatomy and neuroimaging. The next section on cerebellar malformations deals with a variety of topics including agenesis, hypoplasia, congenital ataxias, Dandy-Walker malformation, Joubert syndrome, Chiari I and II, rhombencephalosynapsis, posterior fossa cysts, and a relatively newly described malformation called pontine tegmental cap dysplasia. In each relatively short chapter in this section, the authors bring together clinical and imaging features, genetics, diagnostic criteria, and ideas regarding pathogenesis.

Novel Clinical Features in Pontine Tegmental Cap Dysplasia

Pontine tegmental cap dysplasia is a rare neurologic condition first described by Barth et al. in 2007. It is characterized by a vaulted pontine tegmentum projecting into the fourth ventricle and ventral pontine hypoplasia. Patients present with developmental delay, cerebellar and pyramidal abnormalities, cranial nerve dysfunction, and various extracranial malformations. The condition is thought to occur as a result of aberrant neuronal axonal guidance during embryologic development. Its genetic etiology has not been identified. We describe a further case of this rare condition with several features not previously reported, including aortic arch hypoplasia and mirror movements.