Malignant ossifying fibromyxoid tumor of the brain treated with post-operative fractionated stereotactic radiation therapy: A case report and literature review

Background: Ossifying fibromyxoid tumor (OFMT) is a rare musculoskeletal soft-tissue neoplasm of uncertain histogenesis most frequently occurring in the lower extremities. Conventionally, considered benign, these tumors are often managed by surgical resection followed by surveillance. However, malignant OFMTs with an increased propensity for local recurrence and distant metastasis have been recently identified, and the role of adjuvant therapy in these more aggressive cases is unclear. Case Description: We present, to the best of our knowledge, the first reported case of a primary, malignant, and intracranial OFMT. A 29-year-old female presented with recurrent headaches secondary to a large mass in her right frontal lobe. She underwent gross total resection of the brain mass with final pathology consistent with malignant OFMT demonstrating high-risk features including increased cellularity, grade, and mitotic activity. Due to these high-risk features, she received postoperative fractionated stereotactic radiation therapy (FSRT) to the resection cavity, and to the best of our knowledge, she represents the only known patient with OFMT to be treated with adjuvant FSRT. She tolerated the adjuvant treatment well with no acute or late toxicities and remains disease-free over 5 ½ years after resection. Conclusion: Adjuvant FSRT appears to be a safe and efficacious approach for managing this rare intracranial disease presentation. We review this patient’s clinical course in the context of the literature to demonstrate the difficulties associated with accurate diagnosis of this rare tumor and the controversial role of adjuvant therapy in preventing disease recurrence in this patient population.

Fractionated Stereotactic Radiation Therapy Using Volumetric Modulated Arc Therapy in Patients with Solitary Brain Metastases

Purpose. To analyze retrospectively the clinical efficacy and safety for patients treated with fractionated stereotactic radiation therapy (FSRT) using volumetric modulated arc therapy. Methods. Between 2016 and 2017, 46 patients with solitary brain metastasis who underwent FSRT consisting of 25-40 Gy/5 fractions were recruited in this study. All targets within the same course received different prescriptions according to size. Toxicities were graded according to the Common Terminology Criteria for Adverse Events version 4.0. Results. The median follow-up was 11 months (3-53 months). The 6-month and 12-month local control rate calculated by Kaplan-Meier estimate was, respectively, 95% and 86%. Tumor diameter<2.5 cm obtained 100% improved 12-month local control rate compared with 66% in those with ≥2.5 cm (P<0.001). The 12-month local control calculated by Kaplan-Meier estimate was 95% in tumors with >30 Gy treatment and only 60% in tumors with ≤30 Gy treatment (P=0.001). Multivariate analysis revealed that the prescription dose≤30 Gy resulted in increased local failure (hazard ratio (HR), 0.14 (range, 0.019-0.95; P=.046)). Grade 3 or worse toxic effects were found in 5 (11%) patients, and no patient experienced surgical resection for symptomatic radioactive necrosis. Conclusions. FSRT for solid brain metastasis appears to have the advantages of a high rate of local control with a minimal risk of severe toxicity and deserves application in the clinical practice.