Spontaneous regression of epileptogenic pilocytic astrocytoma with FGFR1-TACC1 fusion.

Abstract

Introduction: Pilocytic astrocytoma (PA) is the most common pediatric tumor, typically located in the cerebellum, with spontaneous regression observed mainly in patients with neurofibromatosis type 1 (NF1). However, spontaneous regression of PA without NF1 is rarely reported.

Case presentation: Here, we describe a case of spontaneous regression of PA without NF1, located in the left frontal lobe with FGFR1-TACC1 fusion, in a 14-year-old boy who presented with epilepsy. Initial MRI revealed a lesion in the left middle frontal gyrus, and subsequent follow-up MRI demonstrated spontaneous regression. Despite this regression, the patient's seizures persisted, leading to epileptic focus resection. Pathological examination confirmed PA with characteristic histological findings and FGFR1-TACC1 fusion.

Conclusion: This case suggests that FGFR1-TACC1 fusion may be linked to spontaneous regression of PA, even in the absence of NF1. Surgical intervention may remain necessary in cases of epilepsy associated with PA, regardless of tumor regression.