頭蓋内未分化多形肉腫の管理：系統的レビュー

Undifferentiated pleomorphic sarcoma (UPS) is a rare and aggressive soft tissue tumor of unknown histogenesis. UPS most often arises in the extremities or trunk, where wide surgical excision is feasible. Rarely, UPS involves the intracranial space, where critical structures may inhibit complete resection. Given its rarity and historical misclassification as malignant fibrous histiocytoma (MFH), knowledge of intracranial UPS is limited, and there are no clear treatment guidelines. We systematically reviewed all available cases of intracranial UPS to consolidate existing literature and assess prognosis and management considerations. A systematic review was conducted according to PRISMA guidelines. PubMed and Embase were searched for reports of intracranial UPS or storiform-pleomorphic MFH. Eligible studies included at least one histologically confirmed case treated with surgery, chemotherapy, or radiotherapy and reported outcomes. Data on demographics, tumor location, treatment, follow-up, and survival were extracted. Event-free survival (EFS) and overall survival (OS) were analyzed by treatment modality, age, sex, and tumor location using Kaplan-Meier and log-rank tests. From 801 records, 40 studies with 48 patients were included. The median age was 45 years, and 50% were female. 15% had prior radiotherapy. Most tumors were extra-axial (45%) and nearly all patients underwent surgery, with 82.1% achieving gross total resection. Median EFS and OS were 18 and 24 months, respectively. No survival differences were seen by treatment modality, age, or sex. Overall survival was longer for extra-axial tumors compared to intra-axial or skull base tumors (p = 0.016). Intracranial UPS is a rare and aggressive tumor, with worse prognosis compared to those that are extracranial. Among factors that we evaluated, extra-axial location was the strongest positive prognostic factor. Surgical resection with adjuvant chemoradiation showed the longest median survival. Ongoing case reports are required to refine management guidelines and improve patient outcomes.