Neuroradiological spectrum of sarcoma intracranial metastases: a single center study

Sarcomas are a heterogeneous group of rare tumors sharing a common origin from connective or other non-epithelial tissues. Although clinical case series of intracranial sarcoma metastases have already been published, their neuroradiological findings are poorly known. This study aims to describe their CT and MRI features. Patients followed-up for intracranial sarcoma metastases at a tertiary referral center between January 2011 and April 2024 were included. Patients with no pretreatment brain imaging, and those whose lesions were confined to the skull were excluded. Two neuroradiologists, blinded to pathology, assessed number and location of metastases, size of the largest lesion, morphology, perilesional edema, occurrence of calcification, hemorrhage, cysts, necrosis, and leptomeningeal disease, CT density and MR signal intensity before and after intravenous contrast administration, Apparent Diffusion Coefficient mean values, and perfusion features. Pre-treatment imaging was assessed in 22 patients (15 MRI, 18 CT) with 12 different tumor types. Ten patients had multiple metastases at presentation, while one patient had diffuse leptomeningeal seeding. Lesions were heterogeneous before and after intravenous contrast administration both among different tumor types and between different lesions in the same patient with multiple metastases. However, all three chondrosarcoma patients showed the T2-FLAIR mismatch sign, all Ewing sarcoma patients had exclusively pachymeningeal disease and lesions in osteosarcoma patients showed gross calcification. These features were absent or uncommon in the other subtypes. In addition, one chondrosarcoma patient had a mixture of brain metastases and multiple neoplastic emboli and one leiomyosarcoma metastasis was visible only on DWI. Intracranial sarcoma metastases are strikingly heterogeneous. Some candidate type-associated imaging features have been observed; their potential clinical utility requires confirmation in larger multicenter cohorts.