Pediatric Medulloblastoma with Postoperative Complications and an Incidental Optic Pathway Glioma: A Case Report
Fatima Mahmood *1, Sadia Sadiq 1, Usama Javed 2, Samina Siddique 3, Faieqa Aslam 3
*Correspondence to: Fatima Mahmood, Institute of Nuclear Medicine and Oncology, Lahore.
Copyright
© 2025 Fatima Mahmood is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Received: 09 September 2025
Published: 15 September 2025
DOI: https://doi.org/10.5281/zenodo.22767856
Abstract
We report the case of a 14-year-old boy diagnosed with a posterior fossa medulloblastoma who exhibited progressive neurological symptoms. Preoperative MRI revealed a large, well-defined lesion centered at the fourth ventricle with both superior and inferior extensions. Surgical resection confirmed WHO Grade IV medulloblastoma on histopathology. Postoperatively, the patient developed complications, and follow-up imaging revealed a residual lesion as well as a new, incidental optic chiasmal mass consistent with an optic pathway glioma. The patient was planned for craniospinal irradiation (CSI) using 36 Gy in 20 fractions with concurrent vincristine chemotherapy, and a 10-fraction boost (18 Gy) to both medulloblastoma and optic glioma. This case highlights the importance of vigilant postoperative imaging, recognition of secondary pathologies, and a multidisciplinary treatment approach in pediatric neuro-oncology.
Introduction
Central nervous system (CNS) tumors have the second-highest frequency of pathogenic germline mutations among pediatric cancers. Among CNS tumors, medulloblastomas show the second highest mutation rate, with pathogenic variants identified in 13.5% of cases [1]. Medulloblastoma is the most common malignant pediatric brain tumor, typically presenting at a median age of 7 years, with a male predominance [2]. These tumors often obstruct cerebrospinal fluid (CSF) flow, resulting in increased intracranial pressure and symptoms such as morning headaches, vomiting, and ataxia [3].
Optic pathway gliomas (OPGs) are low-grade tumors involving the precortical visual pathways and account for 2–5% of pediatric CNS tumors [4]. They may occur sporadically or in association with neurofibromatosis type 1 (NF1) [5]. OPGs display variable growth patterns, making management complex and typically guided by the degree and progression of visual impairment rather than size alone [6].
Case Presentation
A 14-year-old boy, presented to our hospital on March 20, 2025, with a six-month history of progressive neurological symptoms, including gait instability, left-sided weakness, persistent headaches, declining vision in the left eye, and dysarthria. Neurological exam revealed left hemiparesis (Grade 3/5), ataxic gait, dysarthric speech, and reduced left-eye visual acuity with early optic disc pallor.
Patient had first presented to Children Hospital Lahore in September 2024, with the history of headache and postural instability for six months. MRI brain with contrast showed a 50 x 52 x 50 mm heterogeneous lesion in midline of posterior fossa with mass effect on 4th ventricle, causing retrograde hydrocephalus. He had previously undergone ventriculoperitoneal (VP) shunting at Children’s Hospital Lahore in December 2024 for papilledema, which provided temporary relief. Following symptom progression, he underwent further neuroimaging.
Thus, an MRI brain with contrast on January 25, 2025, revealed a large 5.5 × 7.0 × 7.7 cm lesion centered at the fourth ventricle, extending superiorly into the quadrigeminal cistern and inferiorly through the foramen magnum. The mass appeared isointense on T1, hyperintense on T2/FLAIR, and contained cystic/necrotic regions. Preoperative spinal MRI revealed no evidence of spinal metastases.
On January 27, 2025, suboccipital craniectomy with subtotal resection of tumor was performed at Lahore General Hospital. Histopathology confirmed classic WHO Grade IV medulloblastoma. The resected specimen measured 32 x 23 x 4 mm and was immunopositive for synaptophysin and with retained INSM1 expression, suggestive of SHH or Group 4 molecular subtype. Subsequently, the postoperative CT Brain plain showed expected postsurgical changes and a hypodense non-enhancing collection measuring 42 x 42 mm in midline of posterior fossa, causing obliteration of the 4th ventricle. Patient was lost to follow-up for two months.
By March 20, 2025, the patient reported worsening vision. MRI performed on April 9, 2025 revealed a 2.2 × 1.5 cm residual or recurrent lesion in the right cerebellar hemisphere and a new 1.4 × 1.2 × 1.3 cm enhancing lesion at the optic chiasma consistent with an optic pathway glioma. No spinal dissemination was detected.
Given the evidence of residual medulloblastoma and incidental optic glioma with visual decline, the patient was categorized as high risk medulloblastoma (due to residual disease >1.5cm² postoperatively). Treatment was tailored in a multidisciplinary setting involving neuro-oncology, radiation oncology, and ophthalmology, considering both tumor control and visual preservation. The patient was scheduled for craniospinal irradiation (CSI) (36 Gy in 20 fractions) with concurrent vincristine followed by an 18 Gy boost to both the posterior fossa tumor bed and the optic pathway glioma. Unfortunately, the patient became hemodynamically unstable and expired after receiving 15 fractions.
MRI images are not available as the patient`s family has lost them, only CT SIMULATION images are available in the hospital record. Following is the CT SIM showing hypodensities at posterior fossa and optic chiasma indicating medulloblastoma and optic glioma respectively.
The CTV is the whole cranial and spinal meninges. Particular attention was given to the cribriform fossa, the temporal lobes of the brain and the base of skull and nerve cranial foramina. In the spine, the meninges extend along the nerve roots so the intervertebral foramina should be included.OARs have also been delineated following the guidelines.
Discussion
The co-occurrence of medulloblastoma and optic nerve glioma in a pediatric patient represents an exceptionally rare clinical scenario, with few cases reported in the literature (7). Both of these central nervous system (CNS) tumors are well-characterized individually in pediatric oncology; however, their synchronous or metachronous presentation in the same patient raises important considerations regarding diagnosis, treatment planning, and long-term outcomes.
Medulloblastoma (MB) is the most common malignant CNS tumor in children, comprising 15–20% of all pediatric CNS neoplasms and 64% of pediatric embryonal tumors (8,9). Clinical symptoms typically include intracranial hypertension and posterior fossa mass effect, manifesting as headache, nausea, ataxia, and visual disturbances (10). Histologically, MB is classified into four subtypes: classic (68–80%), desmoplastic/nodular (7%), MB with extensive nodularity (3%), and large cell/anaplastic (10–22%), the latter associated with a more aggressive course (11). In this case, the patient presented with classic symptoms of a posterior fossa tumor, including gait instability, left-sided weakness, dysarthria, and headaches. MRI revealed a large lesion centered in the fourth ventricle with superior and inferior extension, consistent with typical medulloblastoma radiological patterns.
In contrast, optic pathway gliomas are typically low-grade astrocytomas, often pilocytic, and frequently associated with neurofibromatosis type 1 (NF1) (12). However, this patient did not exhibit clinical stigmata of NF1, suggesting a sporadic optic glioma. A new optic chiasmal lesion identified on follow-up imaging coincided with the patient’s progressive visual decline. While optic gliomas have been sporadically reported as secondary CNS neoplasms, the timing in this case suggests a coincidental, rather than treatment-induced, etiology.
In 1977, G. R. Bhangui reported the case of multiple primary brain tumors in a 12-year-old girl, including medulloblastoma, optic nerve glioma, ganglioglioma, and pilocytic astrocytoma (7). Another case describes the synchronous occurrence of glioblastoma and medulloblastoma in a 5-year-old boy with suspected cancer predisposition syndrome (13). To our knowledge, this is the second documented case of both medulloblastoma and optic nerve glioma occurring simultaneously in the pediatric population.
While no direct causal relationship between optic nerve gliomas and medulloblastomas has been definitively established, recent studies suggest that aberrant Sonic Hedgehog (Shh) signaling may be implicated in both entities (14, 15). The Shh signaling pathway plays a critical role in neural development, acting as a mitogen for precursor cell populations in the brain, retina, optic stalk, and cerebellum (16). Dysregulation of this pathway, particularly in cerebellar granule neuron precursors, is known to drive the development of the Shhsubtype of medulloblastoma (17). Growing evidence also implicates this pathway in the pathogenesis of other CNS tumors, including gliomas (18,19). (MDT and vigilant approach is warranted.....).
References