Myxofibrosarcoma (MFS) is a rare, aggressive soft tissue sarcoma primarily affecting older adults. Despite curative-intent surgery and multimodal therapy, outcomes remain variable. Acute kidney injury (AKI) and sarcopenia are known complications in oncologic care, but their incidence and impact in MFS patients remain unclear.

To assess the incidence and consequences of AKI in adult MFS patients undergoing curative-intent surgery, and its association with survival, CT-based sarcopenia progression, and postoperative morbidity.

In this retrospective single-center study, 49 adults with high-grade, N0M0 MFS who underwent curative-intent resection with or without multimodal therapy were included. AKI was defined as a ≥ 0.3 mg/dL increase in serum creatinine. Sarcopenia and adipose tissue loss were assessed via serial CT morphometry scans at the L3 lumbar level. Associations between AKI and clinical outcomes (survival, function, length of hospital stay, surgical site infection) were evaluated using regression and survival analyses.

AKI occurred in 38.8% of patients and independently predicted decreased overall survival (HR 6.73; p = 0.0005). AKI was associated with accelerated loss of muscle tissue and visceral fat (all p < 0.001), functional decline (ECOG, p = 0.0078), longer hospitalization (p < 0.001), and increased wound infections (52.6% vs. 10.0%; p < 0.0001).

This is the first study to identify AKI as an independent predictor of mortality and sarcopenia in surgically treated MFS patients. CT morphometry may aid in early risk stratification, while renal monitoring offers a potential target for improving outcomes through nephroprotective strategies.