Dedifferentiated Liposarcoma: Two Case Reports of Retroperitoneal and Paratesticular Presentations with FDG PET/CT Findings

Dedifferentiated liposarcoma (DDLPS) is a rare and aggressive soft tissue sarcoma most commonly arising in the retroperitoneum, but it can also occur in uncommon sites such as the paratesticular region. We present two cases of DDLPS with distinct clinical presentations and highlight the diagnostic and prognostic utility of 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT). The first case describes a retroperitoneal DDLPS in a female patient with intense FDG uptake. In contrast, the second case presents a paratesticular DDLPS in a male patient with recurrence and metastatic progression on PET/CT imaging despite chemoradiotherapy. These cases emphasize the role of FDG PET/CT in staging and biopsy guidance and in monitoring treatment response and prognosis.