Fibromyxoid sarcoma in the retroperitoneum

Rationale: Low-grade fibromyxoid sarcoma (LGFMS) is a pathological type of fibrosing fibrosarcoma that appears as a distinctive soft tissue masse with bland histological features. It is mostly located in the deep soft tissues of the extremities. Computed tomography (CT) plays an important role in diagnosing fibrosing fibrosarcoma in the abdomen. To date, several studies in the literature have reported on CT features of LGFMS. Patient concerns and Diagnoses:We report another case of LGFMS, which presented with certain unique CT feature. The anterolateral region and the wall of the cystic nodules showed gradual enhancement and several nourishing vessels were seen after contrast administration. These imaging features were consistent with the histologic findings of LGFMS. Interventions andOutcomes: The patient underwent tumorectomy and implantation of radioactive implants. Two years after the operation, 1 metastasis mass occur in the right psoas major. Lessons: These CT features in LGFMS may be useful to assess the histological characteristics of LGFMS to facilitate preoperative diagnosis in the clinical setting and provide the supplemental imaging knowledge for future studies. Abbreviations: CT = computed tomography, LGFMS = low-grade fibromyxoid sarcoma.