Abstract: A case of malignant inflammatory myofibroblastoma was reported. The characteristics of the disease were analyzed using clinical symptoms, CT, ¹⁸F-FDG PET/CT examination, clinical diagnosis, pathological diagnosis, and prognosis. The understanding of this disease was deepened through literature review. The case was verified as malignant inflammatory myofibroblastoma. The disease progresses quickly and had low specificity. Diagnosis needed pathology and prognosis. Myofibroblastoma is mostly benign, and the incidence of malignant diseases is small. Once myofibroblastoma occurs, it is easy to misdiagnose. Thus, a combination of clinical, imaging, pathological, therapeutic, and prognostic considerations is needed.