We present the first case of pontine tegmental cap dysplasia (PTCD) reported in South Africa, involving a one-year-old girl with bilateral sensorineural deafness, global atrophy, hemivertebrae, and butterfly vertebrae. Clinical examination revealed subtle dysmorphic features, abnormal corneal sensation, bilateral strabismus, and uncertain visual acuity. Magnetic resonance imaging (MRI) demonstrated key diagnostic features, including ventral pons hypoplasia, ectopic dorsal pontine tissue, and cranial nerve abnormalities such as hypoplasia of the facial nerves, absent right vestibulocochlear nerve, and non-branching left vestibulocochlear nerve. A review of the literature highlights the importance of advanced neuroimaging techniques, such as MRI and diffusion tensor imaging (DTI), in identifying the structural aberrations and potential axonal guidance abnormalities associated with PTCD. This case report aims to shed light on this rare condition's intricacies and emphasize the need for further research to deepen our understanding and enhance patient care outcomes.

Objective: To summarize the clinical and imaging presentations of the pontine tegmental cap dysplasia (PTCD). Methods: The clinical, high resolution CT(HRCT) and MRI materials of 4 patients with PTCD between August 2007 to December 2024 were retrospectively analyzed. Among these, there were 2 males and 2 females, their ages ranged from 10 months to 16 years. Results: Of 4 PTCD patients, severe or profound severe hearing loss (n=8 ears), developmental delay, hypotonia and severe facioplegia (n=3 cases) were found. On HRCT, all of 4 cases were associated with temporal anomalies [including a narrow bony cochlear nerve canal (n=8 ears), duplicated (each n=4 ears) or narrow (n=1 ear) internal auditory canal, enlarged vestibular aqueduct (n=2 ears), enlarged vestibules and dysplastic lateral semicircular canals (n=3 ears), ossicular deformation(n=2 ears). The stenosis of the labyrinthine segments of the facial nerve canal (n=3 ears) and facial nerve canal ectopia(n=6 ears)], atrial or ventricular septal defect (each n=1 case), thoracic or lumbar vertebral anomalies and ribs fusion (n=3 cases). On the brain MRI, the variable flattening of the ventral pons and dysmorphism of the dorsal upper pons cap-like bulging and protruding in the fourth ventricle were shown in all cases, the vermian and cerebellar peduncles hypoplasia gave rise to a molar tooth appearance. The dysplastic (n=3 ears), aplastic(n=5 ears) cochlear nerves and dysplastic facial nerves (n=3 ears) were found. Conclusion: The PTCD patients usually present severe hearing loss, developmental delay, hypotonia, and facioplegia. The flattening of the ventral pons and the dorsal upper pons cap-like bulging usually with duplicated internal auditory canal and severe facial and auditory nerves dysplasia are its imaging features. 目的： 总结脑桥被盖“帽状”发育不良（pontine tegmental cap dysplasia，PTCD）患者的临床表现和影像学特征。 方法： 回顾性分析2007年8月至2024年12月山东省第二人民医院诊断为PTCD的4例患者（男2例、女2例，年龄10个月~16岁）的临床表现和颞骨高分辨率CT（HRCT）及颅脑MRI影像学特征。 结果： 4例PTCD患者出生后均表现为双耳重度或极重度听力损失，3例伴有发育迟缓、肌张力低及严重面神经麻痹，3例脊柱和/或肋骨畸形，1例房间隔缺损，1例室间隔缺损。颞骨HRCT上4例（8耳）均伴发颞骨畸形，其中蜗神经管狭窄8耳、内听道重复畸形4耳、内听道狭窄1耳、前庭导水管扩大2耳、前庭和外侧半规管畸形3耳，锤骨发育畸形2耳，面神经管迷路段狭窄3耳、面神经管迷路段移位6耳。颅脑MRI上均显示桥脑前缘不同程度变扁，后缘呈帽状凸起，向第四脑室内突出；小脑及小脑中下脚发育不良，在通过菱脑峡部轴位图像上呈磨牙征；3耳蜗神经发育细小、5耳蜗神经未发育，3耳面神经发育细小。 结论： PTCD患儿临床上常表现为严重听力损失，发育迟缓、肌张力低及面神经麻痹；影像学表现为桥脑前缘扁平、后缘凸起，常伴发内听道重复畸形和面、听神经发育不良。.

Pontine Tegmental Cap Dysplasia (PTCD) is a rare hindbrain malformation characterized by cranial nerve dysfunction, cerebellar abnormalities, and developmental delays of varying severity. This case report presents a 12-month-old female with significant developmental delays, hypotonia, and cranial nerve abnormalities. The findings underscore the critical role of radiology and neuroimaging in diagnosing and managing PTCD. Additionally, this case highlights the importance of neuroimaging in differentiating PTCD from other possible diagnoses and malformations.

This case report highlights vertebral segmental anomalies and the fact that the child presented has a rare neurologic condition called pontine tegmental cap dysplasia. Additionally, this case aims to educate learners in developing a differential diagnosis for vertebral and cardiac anomalies such as VACTERL syndromes and common syndromes associated with butterfly vertebrae in children and adolescents.