Hemorrhagic presentation of a DICER-1-mutant primary intracranial sarcoma with negative MR spectroscopy: illustrative case.

backgroundSpontaneous intraparenchymal hemorrhage (IPH) carries significant morbidity and mortality. The etiology of secondary spontaneous IPH, which results from an underlying mass lesion or vascular anomaly, may be obscured on radiographic investigation by the overlying hemorrhage, even when advanced imaging modalities are used. This may lead to a delay in both diagnosis and initiation of targeted therapy. OBSERVATIONS: A 55-year-old man presented multiple times over an approximately 5-month period with recurrent, symptomatic right frontal IPH. During his initial evaluations, multiple imaging modalities, including MR spectroscopy, failed to identify an underlying lesion. Only on his most recent presentation did MRI demonstrate evidence of a hemorrhagic mass, which was subsequently resected and found to be a primary intracranial sarcoma. LESSONS: This case demonstrates the need to interpret negative MR spectroscopy results with caution in cases of hemorrhagic neoplasms. Furthermore, it highlights the difficulty when determining optimal resection timing in cases of spontaneous IPH without a clear etiology. https://thejns.org/doi/10.3171/CASE25899.