Solitary fibrous tumor in the pineal region: A series of 5 cases and literature review.

Solitary fibrous tumors (SFTs) are fibroblastic mesenchymal neoplasms defined by the presence of a NAB2::STAT6 fusion and exhibit a broad range of behaviors. SFTs in the pineal region are poorly understood due to the limited number of reported cases. Here, we report a 48-year-old woman with a pineal region SFT who subsequently developed metastatic left para-falcine parieto-occipital and right lung upper lobe SFTs over the next 12 years. This was the only pineal SFT identified in an institutional cohort of 34 resected pineal region lesions. Review of another, much larger institutional cohort of pineal region lesions revealed 4 additional patients with SFT but none with extracranial metastasis. We present descriptions of their clinical presentations, treatments, histopathologic findings, available genomic alterations, and longitudinal outcomes. Finally, we performed a comprehensive literature search and identified 19 individual patients with pineal region SFTs. None of these reported neoplasms had an extracranial metastasis. Taken together, this work contributes to the growing body of data characterizing this rare tumor with aggressive potential and reinforces SFTs as a possible differential diagnosis for pineal region tumors.