High-grade astrocytoma with piloid features: case report and systematic review

: In 2021, a new type of tumor was defined according to the new WHO classification (high-grade astrocytoma with piloid features, HGAP). Morphological and neuroimaging differences of HGAP from pilocytic astrocytoma complicate diagnosis. Now, significant detection of this tumor is possible only using molecular genetic testing, in particular, methylation profile analysis.

Objective: To present a patient with HGAP and perform a systematic review of studies devoted to adults with HGAP regarding clinical course, diagnosis, protocols and treatment outcomes. Material and

Methods: Selection of studies was carried out in accordance with the PRISMA recommendations. The authors analyzed the studies independently of each other. All data were systematized. A case report was described jointly with attending physicians and pathologists. Results and discussion: HGAP is characterized by rapid progression and resistance to therapy. This case illustrates the importance of awareness of neurosurgeons and necessitates molecular genetic tests to identify this group of tumors.

Conclusion: HGAP is a rare and aggressive tumor. Treatment algorithm for such patients has not yet been developed. The world experience of treatment is presented by individual series. Analysis of methylation profile is necessary for patients with atypical course of tumors similar to pilocytic astrocytoma.