|Year : 2021 | Volume
| Issue : 3 | Page : 137-139
Retroperitoneal dedifferentiated liposarcoma with a compressed invasion-free kidney: A rare case report
Shang-Rong Zhong1, Thomas Y Hsueh1, Jung-Mao Chou2
1 Divisions of Urology, Ren-Ai Branch, Taipei City Hospital, Taipei, Taiwan
2 Divisions of Pathology, Ren-Ai Branch, Taipei City Hospital, Taipei, Taiwan
|Date of Submission||16-May-2020|
|Date of Decision||22-Aug-2020|
|Date of Acceptance||29-Oct-2020|
|Date of Web Publication||28-Sep-2021|
Thomas Y Hsueh
No. 10, Sec. 4, Ren'ai Road, Da'an Dist., Taipei 10629
Source of Support: None, Conflict of Interest: None
A 68-year-old female patient presented an evident drop in weight within half a year. A heterogeneous huge tumor was found in the left retroperitoneal space through a nonenhanced abdominal computed tomography. The tumor contributed mass effect on adjacent organs and structures, with equivocal left kidney outline. Enhanced kidney magnetic resonance imaging illustrated its hyper-vascular content and clear border. Radical excision was performed through an open approach. The mass was 25 cm in length and weighed about 5 kg. Grossly, it was accompanied by a compressed but invasion-free kidney. The diagnosis of dedifferentiated liposarcoma was made, and a focally involved margin was identified. The average annual incidence of retroperitoneal sarcomas is 2.7 cases/million. Retroperitoneal soft-tissue sarcoma seldom induces symptoms until the tumor makes a mass effect on adjacent organs. The tumor of this patient stands out as the compressed, yet invasion-free left kidney. Surgical resection is regarded as the only potential curative therapy. Due to the large size at presentation and wide extent of the tumor, it often results in limited resectability or positive margin. Important prognostic factors of retroperitoneal sarcoma involve surgical margin, tumor grade, differentiation, and histologic subtype. Dedifferentiated liposarcoma has a worse prognosis and a positive gross margin implies a higher chance of local recurrence as well as a higher mortality rate.
Keywords: Case report, dedifferentiated liposarcoma, retroperitoneal soft tissue sarcoma
|How to cite this article:|
Zhong SR, Hsueh TY, Chou JM. Retroperitoneal dedifferentiated liposarcoma with a compressed invasion-free kidney: A rare case report. Urol Sci 2021;32:137-9
|How to cite this URL:|
Zhong SR, Hsueh TY, Chou JM. Retroperitoneal dedifferentiated liposarcoma with a compressed invasion-free kidney: A rare case report. Urol Sci [serial online] 2021 [cited 2022 Dec 4];32:137-9. Available from: https://www.e-urol-sci.com/text.asp?2021/32/3/137/326935
| Introduction|| |
Retroperitoneal soft-tissue sarcoma (RPS) is a rare disease, making up to 10%–15% of all soft-tissue sarcomas, and around 80% of the tumors arising from the retroperitoneal space are malignant. RPS has a wide spectrum, including liposarcoma, leiomyosarcoma, and undifferentiated/unclassified soft-tissue sarcoma. Among them, liposarcoma is the most common type and can be further classified in accordance with the degree of differentiation as well as the lipid distribution. Immunohistochemistry can assist in identifying liposarcoma, either well-differentiated or dedifferentiated, when MDM2 (Mouse Double Minute 2)/CDK4 (Cyclin-dependent kinase 4); protein overexpression is found. Among the above-mentioned two kinds, dedifferentiated liposarcomas characterize poorly differentiated content, sometimes with the existence of clearly divided nonlipogenic sarcomatous tissue within a well-differentiated counterpart. Compared to the other subtype, dedifferentiated liposarcomas are more life-threatening with aggressive behavior, featuring a higher metastatic rate, local recurrence rate, and mortality. The current paper reports a rare case of dedifferentiated liposarcoma in the retroperitoneal space.
| Case Report|| |
A 68-year-old female patient visited the Family Medicine Clinic in Taipei City Hospital, Renai Branch on July 28, 2018, for an evident drop in body weight of 6 kg (66–60 kg) within half a year. She also complained of abdominal pain, abdominal fullness, and lower back soreness which had lasted several months. General examination, including blood routine, showed no significant abnormality except for mild anemia (10.5 g/dl) and leukocytosis (10,970/μl). A chest x-ray found an elevated left diaphragm whose cause was uncertain. Finally, a heterogeneous huge tumor, 25.0 cm × 16.3 cm × 19.0 cm in size and possibly of kidney origin, was found in the left retroperitoneal space through nonenhanced abdominal computed tomography (CT) 1 month later [Figure 1]a. The tumor occupied the left abdomen, contributing to the marked mass effect on adjacent organs and structures. The left kidney outline was equivocal and the left adrenal was unidentifiable on the CT image.
|Figure 1: (a) Nonenhanced computed tomography, axial view. Huge soft tissue mass in the retroperitoneal space with no obvious left kidney outline (b) T2 weighted magnetic resonance imaging, axial view. Heterogeneous nature of the tumor and its clear border with neighboring organs|
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The subsequent enhanced kidney magnetic resonance imaging (MRI) [Figure 1]b illustrated the hypervascular content of the tumor and its clear border with other organs such as the stomach, pancreas, and aorta. Finally, the bone scan showed no obvious metastatic lesion.
The retroperitoneal tumor debulking surgery was then performed on September 11, 2018. A midline incision from the xiphoid process to 3 cm below the umbilicus was made. There was adhesive tissue connecting the tumor to the diaphragm, and this was damaged during dissection. Owing to the intact surface and loose connection with other parts of the structure, the patient received left radical nephrectomy along with tumor excision, and left diaphragm repair.
Grossly, the mass was 25.5 cm × 24.0 cm × 16.5 cm in size and weighed about 5 kg. It was yellow-gray, mildly firm in consistency, and accompanied a compressed yet invasion-free kidney, which was sized 14.5 cm × 2.2 cm × 1.8 cm [Figure 2]a. Microscopic examination demonstrated undifferentiated anaplastic neoplasm with marked pleomorphic, hyper-cellular spindle cells [Figure 2]b. CDK4 and MDM2 marker were positive in the immunohistochemical stains. A diagnosis of dedifferentiated liposarcoma was therefore made, and the focally involved margin was also identified.
|Figure 2: (a) Gross appearance of the retroperitoneal tumor. Compressed left kidney (sized 14.5 cm × 2.2 cm × 1.8 cm) without invasion was shown between the white arrows. (b) (H and E, ×200) Pleomorphic and hypercellular spindle cells with obvious mitotic activity|
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The postoperative course was relatively smooth except for increased pleural effusion over the left lung, which was more likely due to leakage from the abdominal cavity. The left thoracentesis was performed 6 days after the operation and drained out 550 ml of the bloody fluid. No malignant cell was found in the specimen. During the whole hospitalization course, no other event of pleural fluid accumulation was noted. The patient was discharged on September 28, 2018 under stable conditions. The following adjuvant radiation therapy at tumor bed (6600cGy/33fx) was smoothly completed from October 22, 2018 to December 05, 2018. A 2-year follow-up was conducted with satisfactory results.
| Discussion|| |
Retroperitoneal sarcomas are extremely rare diseases, with an average annual incidence rate of about 2.7 per million. According to the histological nature, liposarcoma can be divided into well-differentiated, dedifferentiated, myxoid, round cell, and pleomorphic liposarcoma, with the first two types making up the bulk of the cases.
RPS seldom induces symptoms until the tumor is big enough to cause mass effect on the adjacent organs. In the current case, the patient sought medical advice at the time she found abnormal loss of weight and early satiety, which was probably the consequence of bowel obstruction and rapid tumor growth. Physical examination at the clinic also manifested a large nontender mass over the left abdomen. The mass was later found to be 25.0 cm × 16.3 cm × 19.0 cm in size.
Diagnostic tools include laboratory studies of tumor markers, biopsy, CT, or MRI. The radiographic features of CT in liposarcomas are based on the heterogeneous nature, containing varying amounts of soft-tissue, fatty mass, and maybe some necrotic tissues. Furthermore, MRI plays a role in depicting the better nature and margin of the tumor. A preoperative needle biopsy may also be performed while a low tumor seeding rate occurs in the biopsy tract, especially when the diagnosis might determine the treatment choice.
Adapting the latest edition (8th edition, 2017) of staging defined by the American Joint Committee on Cancer and Union for International Cancer Control, the pathology result of the patient was dedifferentiated liposarcoma with staging pT4NXMB, FNCLCC (Federation Nationale des Centres de Lutte le Cancer) Grade 3, which is normally associated with a negative prognosis.
The treatment guideline for retroperitoneal sarcoma is still absent. Surgical resection is regarded as the only potential way to cure the disease when the free margin of the tumor is achieved. Yet, as in the current case, due to the large size at presentation and wide extent of the tumor, it often results in limited resectability or microscopically positive margin. Pre- or post-operative adjuvant therapy, like radiation or chemotherapy may be used, taking into account the histologic differentiation, grade, chemo-sensitivity, risk of metastasis, and surgical margin of the tumor. In a retrospective study, postoperative radiation therapy was shown to reduce the risk of local recurrence. Important prognostic factors of retroperitoneal sarcoma involve surgical margin, tumor grade, differentiation, and histologic subtype. Dedifferentiated liposarcoma has a worse prognosis compared to other well-differentiated kinds. A positive gross margin implies a higher chance of local recurrence and mortality rates. In one latest retrospective cohort study in 2018, 65 patients suffering from primary retroperitoneal liposarcoma were collected. Primary local recurrence following complete resection happened to 22 of them (33.8%). Ten cases of dedifferentiated liposarcoma held the least median survival time (20.7 ± 12.8 months) and second-lowest survival rate (50.0%) compared to other histological subtypes. The multivariate analysis eventually regarded pathological subtype and histological grade to be independent prognostic factors.
In the current case, the patient had a large high-grade retroperitoneal dedifferentiated liposarcoma with a positive gross margin. With adjuvant radiation therapy, she survived for more than 24 months after the surgery.
Declaration of patient consent
The authors certify that they have obtained appropriate patient consent form. In the form, the patient has given her consent for her images and other clinical information to be reported in the journal. The patient understands that her name and initial will not be published and due efforts will be made to conceal the identity, but anonymity cannot be guaranteed.
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Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2]