Difficult diagnosis of angiomatoid fibrous histiocytoma of the leg mimicking a benign condition

Angiomatoid fibrous histiocytoma is a rarely metastasizing soft-tissue tumor of low-grade malignancy. Here we report a case of angiomatoid fibrous histiocytoma located in the leg of a 15-year-old female. This case is of particular interest due to its radiological features that led to raise two questions concerning the nature of the disease (is it reactive or tumoral?) and its site of origin (within soft tissues or the tibial periosteum?). Here we describe ultrasound, magnetic resonance imaging, computed tomography scan and positron emission tomography findings that helped answer these questions, understand the real nature of the disease and its appropriate treatment. This case shows that a single type of imaging technique may not be sufficient to understand the real nature of a musculoskeletal lesion and that it is necessary to combine all information derived from various imaging techniques in order to correctly diagnose and treat the disease.