Primary Pleomorphic Liposarcoma of the Kidney: A Rare Case Report
Abstract
A rare case of primary pleomorphic liposarcoma arising from the renal parenchyma and initially suspected radiologically to represent renal cell carcinoma.
Liposarcomas are rare malignant soft-tissue sarcomas. Renal liposarcoma accounts for approximately 1–2% of primary renal sarcomas and is an exceptionally rare entity. Patients may present with a renal mass, flank pain or other nonspecific symptoms, while preoperative distinction from more common renal malignancies can be difficult.
A 63-year-old male presented with persistent left flank pain and malaise. He reported vague left-sided abdominal discomfort for one year, unintentional weight loss of 10 kg during the preceding six months and occasional difficulty with urination.
The patient appeared lean and pale. Abdominal examination revealed a large, firm, non-tender and non-mobile mass in the left lumbar region. Hemoglobin was 8.5 g/dL, renal function was normal and urinalysis demonstrated numerous red blood cells and 2–3 pus cells per high-power field with a negative urine culture. Ultrasonography showed a large left renal mass.
Contrast-enhanced CT of the abdomen and pelvis demonstrated an approximately 8 × 10 cm heterogeneously enhancing mass with central necrosis replacing most of the left kidney. The radiological appearance was considered suggestive of renal cell carcinoma.
Following optimization with blood transfusion and appropriate preoperative assessment, the patient underwent open left radical nephrectomy through a transperitoneal approach. Postoperative recovery was uneventful. Histopathological examination demonstrated a high-grade pleomorphic liposarcoma arising from the renal parenchyma with negative surgical margins.
Immunohistochemical staining was negative for Desmin, HMB45, SMA and PAX8, while EMA demonstrated focal positivity. MDM2 and CDK4 testing was not performed.
Primary renal pleomorphic liposarcoma is an exceptionally rare malignancy that may mimic renal cell carcinoma clinically and radiologically. Reporting rare cases and obtaining longer-term follow-up data may contribute to improved understanding of its diagnosis, management and outcomes.
Male patient presenting with left flank symptoms.
Heterogeneously enhancing left renal mass.
Significant anemia requiring preoperative optimization.
Unintentional loss over the preceding six months.
One-Year History of Left-Sided Symptoms
The patient reported persistent left flank pain, malaise and vague left-sided abdominal discomfort for approximately one year, with substantial unintentional weight loss during the preceding six months.
Large Left Lumbar Mass
Examination demonstrated a large, firm, non-tender and non-mobile mass in the left lumbar region. The patient appeared lean and pale, although his vital signs were stable.
Significant Anemia
Hemoglobin was 8.5 g/dL. Renal function remained within normal limits, while urinalysis showed numerous red blood cells and 2–3 pus cells per high-power field. Urine culture was negative.
Initially Suspected Renal Cell Carcinoma
Contrast-enhanced CT demonstrated an 8 × 10 cm heterogeneously enhancing mass with central necrosis replacing most of the left kidney, with imaging features considered suggestive of renal cell carcinoma.
Blood Transfusion & Optimization
The patient’s anemia was addressed with blood transfusion before surgery, followed by appropriate preoperative assessment.
Open Left Radical Nephrectomy
The patient underwent open left radical nephrectomy using a transperitoneal approach. Complete surgical excision was achieved with negative margins.
High-Grade Pleomorphic Liposarcoma
Histopathological examination identified a high-grade sarcomatous tumour arising from the renal parenchyma and consistent with pleomorphic liposarcoma.
Desmin, HMB45, SMA & PAX8 Negative
Immunohistochemical assessment was negative for Desmin, HMB45, SMA and PAX8, with focal EMA positivity.
MDM2 & CDK4 Not Performed
MDM2 and CDK4 testing was not undertaken, which the authors identify as a limitation in further molecular characterization of the tumour.
Uneventful Recovery
No postoperative complications were observed during the one-month follow-up period reported in the case.
Medical Oncology Referral
Following histopathological diagnosis, the patient was referred to medical oncology for further evaluation and was placed on close follow-up.
A Rare RCC Mimic
The case demonstrates the diagnostic challenge presented by primary renal pleomorphic liposarcoma because nonspecific clinical and radiological findings may resemble renal cell carcinoma before definitive histopathological examination.
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Case Report
A report of an exceptionally rare primary pleomorphic liposarcoma arising from the renal parenchyma and initially suspected to represent renal cell carcinoma.
63-Year-Old Male
The patient presented with persistent left flank pain, malaise, left-sided abdominal discomfort, substantial unintentional weight loss and intermittent urinary difficulty.
8 × 10 cm Left Renal Mass
Contrast-enhanced CT demonstrated a heterogeneously enhancing mass with central necrosis replacing most of the left kidney. Imaging initially suggested renal cell carcinoma.
Open Radical Nephrectomy
Following correction of anemia and preoperative optimization, an open left radical nephrectomy was performed through a transperitoneal approach.
High-Grade Pleomorphic Liposarcoma
Histopathological examination demonstrated a high-grade sarcomatous tumour arising from the renal parenchyma, consistent with pleomorphic liposarcoma. Surgical margins were negative.
Focal EMA Positivity
Desmin, HMB45, SMA and PAX8 were negative, while EMA showed focal positivity. MDM2 and CDK4 testing was not performed.
MDM2 & CDK4 Testing Unavailable
The absence of MDM2 and CDK4 testing limited further molecular characterization of the tumour and is explicitly identified by the authors as a limitation of the case.
Uneventful Early Recovery
The postoperative course was uncomplicated during the one-month follow-up period reported. The patient was referred to medical oncology for further evaluation and placed on close follow-up.
495/chairman/R&E/Committee/IKD
Ethical approval to report this case was obtained from the Research and Ethical Committee under approval number 495/chairman/R&E/Committee/IKD.
Written Informed Consent Obtained
Written informed consent was obtained from the patient for publication of the case report and accompanying images. A copy of the written consent is available on request.
Authorship
AH: Wrote the first draft of the manuscript.
All authors reviewed and edited the manuscript and approved
the final version of the manuscript.
Conflict of Interest & Funding
Conflict of Interest:
The authors have no conflicts of interest to disclose in
relation to this work.
Funding:
This case report was not funded by any person or institution.
The publication also states that the research received no
specific grant from any public, commercial or not-for-profit
funding agency.
Not Applicable
No acknowledgements were reported for this case.
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DOI: 10.64573/torgj2605006
Volume 2 · Issue 2 · Special Issue · 2026
The Operating Room Global Journal (TORGJ).
ISSN 3105-3262.
Case Report.
DOI: 10.64573/torgj2605006.
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