Objective:To explore the clinical characteristics and prognosis of primary renal dedifferentiated liposarcoma.Methods:A retrospective analysis was conducted on the clinical data of 10 patients diagnosed with renal dedifferentiated liposarcoma in the First Affiliated Hospital of Zhengzhou University from January 2017 to December 2023. The cohort consisted of 8 males and 2 females, with a mean age of (59.0±6.8) years. Tumors were located in the left kidney in 8 cases and in the right kidney in 2 cases. Presentations included flank or abdominal masses in 4 patients, back pain in 3 patients, and asymptomatic in 3 patients. Imaging studies revealed solitary lesions in 9 cases and multiple lesions in 1 case. The maximum tumor diameter ranged from 95 to 178 mm, with a median of 119.5 mm. CT showed tumors within the renal parenchyma with unclear boundaries and displayed a "slow in, slow out" pattern of gradual enhancement. Clinical staging revealed T 2N 0M 0 in 3 cases, T 3N 0M 0 in 4 cases, T 4N 0M 0 in 3 cases, and T 2N 1M 0 in 1 case. Nine patients underwent radical nephrectomy, including 4 laparoscopic surgeries, 4 open surgeries, and 1 robotic-assisted with thrombectomy. One patient, presenting with multiple lymph node metastases confirmed by PET-CT, underwent a diagnostic biopsy. Postoperative pathological features, follow-up and prognosis were analyzed. Results:Pathological specimens appeared grayish-red, grayish-yellow or grayish-white cut surfaces with soft to moderate texture. Microscopically, tumor cells were ovoid or short spindle-shaped with significant atypia and cytoplasmic vacuoles, with visible pathological mitoses. Six cases showed only dedifferentiated components with tumor giant cells and multinucleated giant cells resembling pleomorphic undifferentiated sarcoma, with focal tumor necrosis. Fluorescence in situ hybridization showed MDM2 gene amplification in all cases. All cases were diagnosed as primary renal dedifferentiated liposarcoma. Pathological staging showed 4 cases as pT 2N 0M 0, 3 cases as pT 3N 0M 0, 2 cases as pT 4N 0M 0, and 1 case lacked pathological staging due to biopsy only. Five patients received postoperative adjuvant therapy, including two pT 2N 0M 0 cases who received immunotherapy and apatinib treatment respectively, with no recurrence. One pT 3N 0M 0 case received anlotinib treatment, with local recurrence after 12 months, followed by radiofrequency ablation combined with chemotherapy. Two pT 4N 0M 0 cases received ifosfamide combined with epirubicin and pirarubicin combined with lobaplatin respectively, with one case showing no progression at 11 months follow-up, and another case developing splenic metastasis 3 months post-surgery, followed by chemotherapy combined with targeted therapy, surviving for 20 months. Among the 4 cases without adjuvant therapy, two pT 2N 0M 0 cases developed multiple metastases within 1 month post-surgery and received immunotherapy combined with targeted therapy and/or chemotherapy, surviving 4-5 months.One of the two pT 3N 0M 0 cases developed local recurrence 2 months post-surgery and received chemotherapy, surviving 6 months, and another pT 3N 0M 0 case developed gluteal subcutaneous metastasis 1 month post-surgery and received immunotherapy combined with targeted therapy, surviving 8 months.One non-surgical pT 2N 1M 0 patient received chemotherapy and survived for 15 months. All patients were followed up for 4-52 months, with a median follow-up time of 11 months. At the last follow-up, 6 patients died and 4 survived. Conclusions:Primary renal dedifferentiated liposarcoma is clinically rare, with atypical symptoms and difficult preoperative diagnosis, relying on pathology for confirmation. Radical nephrectomy is the main treatment method, but surgery alone has poor prognosis with high recurrence and metastasis rates. Adjuvant therapy based on surgery may improve patient prognosis.Larger sample studies are needed for confirmation.

Objective:To explore the clinical characteristics and prognosis of primary renal dedifferentiated liposarcoma.Methods:A retrospective analysis was conducted on the clinical data of 10 patients diagnosed with renal dedifferentiated liposarcoma in the First Affiliated Hospital of Zhengzhou University from January 2017 to December 2023. The cohort consisted of 8 males and 2 females, with a mean age of (59.0±6.8) years. Tumors were located in the left kidney in 8 cases and in the right kidney in 2 cases. Presentations included flank or abdominal masses in 4 patients, back pain in 3 patients, and asymptomatic in 3 patients. Imaging studies revealed solitary lesions in 9 cases and multiple lesions in 1 case. The maximum tumor diameter ranged from 95 to 178 mm, with a median of 119.5 mm. CT showed tumors within the renal parenchyma with unclear boundaries and displayed a "slow in, slow out" pattern of gradual enhancement. Clinical staging revealed T 2N 0M 0 in 3 cases, T 3N 0M 0 in 4 cases, T 4N 0M 0 in 3 cases, and T 2N 1M 0 in 1 case. Nine patients underwent radical nephrectomy, including 4 laparoscopic surgeries, 4 open surgeries, and 1 robotic-assisted with thrombectomy. One patient, presenting with multiple lymph node metastases confirmed by PET-CT, underwent a diagnostic biopsy. Postoperative pathological features, follow-up and prognosis were analyzed. Results:Pathological specimens appeared grayish-red, grayish-yellow or grayish-white cut surfaces with soft to moderate texture. Microscopically, tumor cells were ovoid or short spindle-shaped with significant atypia and cytoplasmic vacuoles, with visible pathological mitoses. Six cases showed only dedifferentiated components with tumor giant cells and multinucleated giant cells resembling pleomorphic undifferentiated sarcoma, with focal tumor necrosis. Fluorescence in situ hybridization showed MDM2 gene amplification in all cases. All cases were diagnosed as primary renal dedifferentiated liposarcoma. Pathological staging showed 4 cases as pT 2N 0M 0, 3 cases as pT 3N 0M 0, 2 cases as pT 4N 0M 0, and 1 case lacked pathological staging due to biopsy only. Five patients received postoperative adjuvant therapy, including two pT 2N 0M 0 cases who received immunotherapy and apatinib treatment respectively, with no recurrence. One pT 3N 0M 0 case received anlotinib treatment, with local recurrence after 12 months, followed by radiofrequency ablation combined with chemotherapy. Two pT 4N 0M 0 cases received ifosfamide combined with epirubicin and pirarubicin combined with lobaplatin respectively, with one case showing no progression at 11 months follow-up, and another case developing splenic metastasis 3 months post-surgery, followed by chemotherapy combined with targeted therapy, surviving for 20 months. Among the 4 cases without adjuvant therapy, two pT 2N 0M 0 cases developed multiple metastases within 1 month post-surgery and received immunotherapy combined with targeted therapy and/or chemotherapy, surviving 4-5 months.One of the two pT 3N 0M 0 cases developed local recurrence 2 months post-surgery and received chemotherapy, surviving 6 months, and another pT 3N 0M 0 case developed gluteal subcutaneous metastasis 1 month post-surgery and received immunotherapy combined with targeted therapy, surviving 8 months.One non-surgical pT 2N 1M 0 patient received chemotherapy and survived for 15 months. All patients were followed up for 4-52 months, with a median follow-up time of 11 months. At the last follow-up, 6 patients died and 4 survived. Conclusions:Primary renal dedifferentiated liposarcoma is clinically rare, with atypical symptoms and difficult preoperative diagnosis, relying on pathology for confirmation. Radical nephrectomy is the main treatment method, but surgery alone has poor prognosis with high recurrence and metastasis rates. Adjuvant therapy based on surgery may improve patient prognosis.Larger sample studies are needed for confirmation.