We present the case of a 62-year-old male patient, with no prior pathologic history, who, in 2004, came to our consultation with a palpable abdominal tumour in the left flank that was not painful and adhered to deep planes. CT scan showed a mass that was probably retroperitoneal in origin and had a myxoid appearance. In addition, a liver nodule was detected, which was probably metastatic (Fig. ...

With the exception of well-differentiated liposarcoma, dedifferentiated leiomyosarcoma, solitary fibrous tumour, malignant peripheral nerve sheath and undifferentiated pleomorphic sarcoma, majority ≈70 histologic subtypes retroperitoneal sarcoma are defined as ‘ultra-rare’ sarcomas, with an incidence ≤1–5/1,000,000 persons/year. For most these ultra-rare RPS subtypes, diagnosis treatment follow...