1. Osteoncology and Rare Tumors Center, Istituto Scientifico Romagnolo per lo Studio e la Cura dei Tumori (IRST) IRCCS, Meldola, Italy
2. Osteoncology and Rare Tumors Center, Istituto Scientifico Romagnolo per lo Studio e la Cura dei Tumori (IRST) IRCCS, Via Piero Maroncelli 40, 47014 Meldola (FC), Italy
3. Department of Orthopedics, Istituto Ortopedico Rizzoli, University of Bologna, Bologna, Italy
4. Pathology Unit, Morgagni-Pierantoni Hospital, Forlì, Italy