An Infant Intracranial Tumor with Nystagmus

An Infant Intracranial Tumor with Nystagmus

This case report details the clinical presentation, diagnostic process, and management of a 4-month-old infant with an intracranial tumor presenting with nystagmus. The patient was brought to the Department of Ophthalmology at the Children’s Hospital, School of Medicine, Zhejiang University, due to sudden eyeball shaking observed over the course of a week. The infant was a full-term gravida 2 para 2 with no history of trauma, surgery, or significant family medical risk factors. The initial ophthalmological examination revealed bilateral horizontal tremor of the eyes, with both eyes demonstrating a light-chasing response. The anterior segment examination was normal, and after mydriasis, a wide-angle retinal imaging system was used to evaluate the fundus. The binocular optic discs appeared clear with normal color and flat retinas. No obvious abnormal exudation or space-occupying lesions were observed, but the left eye showed marked retinal vasodilation with slight distortion.

Given the clinical findings, further imaging was pursued. A skull magnetic resonance imaging (MRI) scan revealed a large tumor in the sellar region. The tumor exhibited extensive skull and brain transplantation in the skull base and spinal canal, accompanied by supratentorial hydrocephalus. The tumor’s location and characteristics suggested a significant mass effect, particularly on the optic chiasm, which was compressed bilaterally within the cavernous sinus. The patient was subsequently admitted to the Neurosurgery Department for tumor resection.

The post-operative pathological examination confirmed the diagnosis of pilomyxoid astrocytoma (PMA). Histopathological analysis revealed that the tumor cells were loose and star-shaped, growing around blood vessels. Immunohistochemical staining was positive for glial fibrillary acidic protein (GFAP), oligodendrocyte transcription factor-2 (Olig2), neuron-specific enolase (NSE), synaptophysin (SYN), and P53 tumor suppressor protein (P53). Staining for CD34 was negative, and epithelial membrane antigen (EMA) and H3K27M were weakly positive or negative. The Ki-67 proliferation index was approximately 15%, indicating a relatively high proliferative activity.

Pilomyxoid astrocytoma is a rare central nervous system tumor, predominantly occurring in the sellar region of infants and young children. The mean age of onset for PMA is around 18 months, making this case particularly notable due to the patient’s younger age of 4 months. The tumor’s location in the sellar region aligns with the most common site for PMA, as reported in the literature. The clinical presentation of PMA often includes symptoms related to increased intracranial pressure, such as papilledema, strabismus, cranial nerve palsies, and abnormal eye movements. In this case, the infant presented with nystagmus, a condition characterized by repetitive, involuntary eye movements initiated by the slow movement of the eyes away from the visual target.

Nystagmus can be classified into two main categories: infantile nystagmus, which typically appears within the first 3 to 6 months of life, and acquired nystagmus (AN), which develops later. Acquired nystagmus is often associated with disturbances in the mechanisms that ensure steady gaze, including visual fixation, the vestibulo-ocular reflex, and the ability to hold the eyes in an eccentric position. In this case, the nystagmus was attributed to the tumor’s location in the sellar region, which impeded the conduction pathways responsible for gaze stabilization. The patient’s nystagmus was consistent with the findings of Lavery et al., who reported that nystagmus in chiasmatic gliomas is more common in younger children.

The clinical presentation of acquired nystagmus often includes additional signs and symptoms, such as oscillopsia (the perception of a moving environment), dissociated (asymmetric) nystagmus, preserved optokinetic nystagmus, afferent pupillary defect, papilledema, and neurological symptoms like vertigo and nausea. In this case, the infant exhibited nystagmus at 4 months of age, along with retinal vasodilation observed during fundus examination. These findings raised suspicion of an intracranial lesion, prompting further neurological and imaging evaluations.

The diagnostic process highlighted the importance of a comprehensive ophthalmological examination in infants and young children presenting with abnormal eye movements. While the anterior segment examination was unremarkable, the fundus examination revealed significant findings that guided further investigation. The use of advanced imaging techniques, such as MRI, was critical in identifying the tumor’s location, extent, and impact on surrounding structures. The pathological diagnosis of PMA was confirmed through immunohistochemical analysis, which provided insights into the tumor’s molecular characteristics and proliferative potential.

The management of PMA typically involves surgical resection, as was performed in this case. The post-operative period is crucial for monitoring the patient’s recovery and assessing the need for additional treatments, such as chemotherapy or radiation therapy, depending on the tumor’s behavior and residual disease. The high Ki-67 index observed in this case suggests a more aggressive tumor, warranting close follow-up and potential adjuvant therapy.

This case underscores the importance of considering intracranial pathology in infants presenting with nystagmus, particularly when accompanied by other neurological or ophthalmological abnormalities. Pediatricians and ophthalmologists should maintain a high index of suspicion for acquired nystagmus in young children and ensure timely referral for neurological and imaging evaluations. The detailed fundus examination, combined with advanced imaging techniques, played a pivotal role in diagnosing and managing this rare but significant condition.

In conclusion, this case report provides valuable insights into the clinical presentation, diagnostic approach, and management of pilomyxoid astrocytoma in an infant. The early onset of nystagmus, combined with retinal vasodilation and intracranial imaging findings, highlights the complex interplay between ophthalmological and neurological pathologies in pediatric patients. The successful diagnosis and treatment of this case emphasize the importance of a multidisciplinary approach involving ophthalmologists, neurosurgeons, and pathologists to ensure optimal outcomes for patients with rare and challenging conditions.

doi.org/10.1097/CM9.0000000000000597

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