A rare presentation of primary lateral ventricle H3 K27-altered diffuse midline glioma in a 14-year-old girl: a case description

Midline Gliomas: A Retrospective Study from a Cancer Center in the Middle East

Midline gliomas are tumors that occur in midline structures and can be circumscribed or diffuse. Classical midline structures include the thalamus, brainstem, and spinal cord. Other midline structures include the corpus callosum, basal ganglia, ventricles, paraventricular structures, and cerebellum. Diffuse midline glioma (DMG) is a diffuse glioma that occurs in the classical midline structures, characterized by a specific genetic alteration, and associated with grim outcome. This study was conducted at King Hussein Cancer Center and reviewed the medical records of 104 patients with circumscribed and diffuse gliomas involving midline structures that underwent biopsy between 2005 and 2022. We included a final cohort of 104 patients characterized by a median age of 23 years and a male-to-female ratio of 1.59-to-1. Diffuse high-grade glioma (DHGG) was the most common pathological variant (41.4%), followed by DMG (28.9%). GFAP was positive in most cases (71.2%). Common positive mutations/alterations detected by surrogate immunostains included H3 K27me3 (28.9%), p53 (25.0%), and H3 K27M (20.2%). Age group, type of treatment, and immunohistochemistry were significantly associated with both the location of the tumor and tumor variant (all; p < 0.05). DMGs were predominantly found in the thalamus, whereas circumscribed gliomas were most commonly observed in the spinal cord. None of the diffuse gliomas outside the classical location, or circumscribed gliomas harbored the defining DMG mutations. The median overall survival (OS) for the entire cohort was 10.6 months. Only the tumor variant (i.e., circumscribed gliomas) and radiotherapy were independent prognosticators on multivariate analysis.

A rare presentation of a spinal diffuse midline glioma in a child: a case report

Our patient had an extremely rare type of pediatric Diffuse Midline Glioma (DMG) with modified H3 K27 that occurred in the cervical spinal cord. Due to its location in the spinal cord, slow clinical presentation with torticollis for 7 months, and the non-specific radiological appearance of this tumour, it was initially considered to be a low-grade glioma. Based on imaging findings, the neurosurgery team performed a complete surgical resection, but the pathological features were consistent with a high-grade, diffuse midline glioma. Therefore, we are reporting a case of an altered high-grade DMG H3K27 glioma, which is difficult to diagnose due to its slow clinical symptoms which caused a delay in diagnosis, non-specific imaging, and with difficulty in accessing histopathological markers in low and middle income countries (LMIC).