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Year : 2021  |  Volume : 35  |  Issue : 2  |  Page : 76-79

Multifocal sarcomatoid urothelial carcinoma of the renal pelvicalyceal system and ureter: A diagnostic dilemma

1 Department of Pathology, Lady Hardinge Medical College, New Delhi, India
2 Department of Pathology, HIMSR, New Delhi, India

Date of Submission06-Oct-2020
Date of Acceptance19-Jun-2021
Date of Web Publication27-Nov-2021

Correspondence Address:
Shivali Sehgal
B-4/125 Safdarjung Enclave, New Delhi
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/jms.jms_103_20

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Sarcomatoid urothelial carcinomas (SUCs) are characterized by intimately mixed malignant epithelial and malignant mesenchymal components. We present a case of a multifocal SUC in the left pelvicalyceal system of the kidney and the left ureter. SUC although rare should be included in the differential diagnosis of multifocal tumors of the renal pelvis and ureter. Immunohistochemistry is essential to confirm the diagnosis and rule out other differentials including pure sarcoma, sarcomatoid variant of renal cell carcinoma, and pseudosarcomatous mesenchymal proliferation.

Keywords: Multifocal, sarcomatoid, urothelial carcinoma

How to cite this article:
Nangia A, Sehgal S. Multifocal sarcomatoid urothelial carcinoma of the renal pelvicalyceal system and ureter: A diagnostic dilemma. J Med Soc 2021;35:76-9

How to cite this URL:
Nangia A, Sehgal S. Multifocal sarcomatoid urothelial carcinoma of the renal pelvicalyceal system and ureter: A diagnostic dilemma. J Med Soc [serial online] 2021 [cited 2022 Oct 4];35:76-9. Available from:

  Introduction Top

Sarcomatoid urothelial carcinomas (SUCs) are characterized by intimately mixed malignant epithelial and malignant mesenchymal components.[1],[2] The epithelial components may be squamous, glandular, or high-grade transitional type, whereas the mesenchymal components may be chondrosarcoma, malignant fibrous histiocytoma, osteosarcoma, leiomyosarcoma, fibrosarcoma, or rhabdomyosarcoma.[3]

SUC can occur in various organs such as the urinary bladder, breast, larynx, esophagus, kidney, and female genital tract;[4],[5] however, in the urinary tract, they occur predominantly in the urinary bladder.[6] The renal pelvis is an extremely rare site of origin for SUC. We present a case of a multifocal sarcomatoid urothelial carcinoma in the left pelvicalyceal system of the kidney and the left ureter.

  Case Report Top

A 75-year-old male presented with swelling on the left side of the abdomen for 2 months. On examination, a large visible swelling was seen in the left hypochondrium and left lumbar regions. Ultrasonography showed an enlarged left kidney with thinned out parenchyma with internal echoes and a calculus measuring 2.3 mm in the pelvis. The upper ureter was dilated and tortuous, lower ureter was obscured. Another calculus was seen in the vesicoureteral junction measuring 6 mm. Contrast-enhanced computed tomography showed a left grossly hydronephrotic kidney with thinning of the parenchyma. The excretory function was altered. An enhancing mass was present in the left renal pelvis of possible neoplastic etiology. There was a renal calculus in the kidney as well as in the left vesicoureteral junction with moderate hydroureter.

Urine cytology done on 3 consecutive days was scantily cellular with no malignant cells identified.

Preoperatively, the left kidney was enlarged with left hydroureteronephrosis. It was adhered to the splenic hilum and tail of the pancreas. Resection of the left hydronephrotic kidney with left hydroureter with mass in the pelviureteric junction along with the spleen and vascular stump was done.

Grossly, the left kidney was grossly enlarged measuring 18 cm × 14 cm × 13 cm. The ureter measured 22 cm in length with diameter varying from 1.5 cm to 1.8 cm. Adrenal gland was not received. No lymph node was identified. The kidney was hydronephrotic with dilated renal pelvis and calyces; peripheral atrophic renal parenchyma, and obliterated renal pyramids. A single stone was identified in the renal pelvis. There was the presence of multiple polypoidal, papillary growths arising from the wall of the renal pelvis and renal calyces varying in size from 0.5 cm × 0.5 cm × 0.5 cm to 4 cm × 4 cm × 3.5 cm. They were gray white, irregular, and friable. The rest of the wall was rough with the presence of numerous papillary excresences. The pelviureteric junction and the entire length of the ureter revealed friable, papillary growths filling the lumen with resected end of the ureter being grossly involved.

Histopathological examination was consistent with the diagnosis of a multifocal sarcomatoid urothelial carcinoma showing both epithelial and mesenchymal differentiation [Figure 1]. There was involvement of the renal pelvicalyceal system, the pelviureteric junction and the full length of the ureter [Figure 2]. The epithelial component consisted of a high-grade carcinoma with transitional and squamous differentiation [Figure 3]. This was positive for pancytokeratin, CK5, CK7 (focal), and epithelial membrane antigen on immunohistochemistry (IHC) [Figure 4]. The sarcomatoid component was seen mainly involving the pelvicalyceal system and showed smooth muscle differentiation [Figure 1]. This was positive for vimentin, smooth muscle actin, CD 10 [Figure 4]. Mitotic activity was 2–3/hpf. Foci of necrosis were present. Lymphovascular invasion was identified. The tumor was invading the wall of the pelvis, and involving the perinephric fat. Renal sinus was involved by tumor. The tumor was involving the surgically resected end of the ureter and invading up to the adventitial coat of the ureter.
Figure 1: Biphasic tumor showing both epithelial and sarcomatoid components (H and E, ×100) with inset showing a higher power view (×400)

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Figure 2: Involvement of the pelvis (below) and ureter (above) by the tumor (H and E, ×100)

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Figure 3: Epithelial component showing both squamous differentiation (H and E, ×100) and transitional differentiation (H and E, ×400)

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Figure 4: Immunohistochemistry findings showing positivity of CK 5 and CK 7 in the epithelial component and Vimentin and smooth muscle actin positivity in the sarcomatous component (×400)

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The rest of the kidney showed the features of chronic pyelonephritis and benign nephrosclerosis.

The spleen was grossly and microscopically unremarkable and free of tumor.

The postoperative course was uneventful; the patient was discharged and lost to follow-up.

  Discussion Top

The terms “sarcomatoid carcinoma” and “carcinosarcoma” have been used together; however, the term “sarcomatoid carcinoma” has been used to describe a malignant spindle cell type tumor with epithelial differentiation, while carcinosarcoma describes a tumor composed of both malignant epithelial and malignant soft-tissue elements.[7] To differentiate the two, IHC is very important. Some authors prefer to use sarcomatoid carcinoma for those cases without heterologous elements in the spindle cell component and carcinosarcoma for cases with heterologous elements.[7] In our case, IHC demonstrated that the tumor was composed of malignant epithelial component with areas of sarcoma. IHC is mandatory for the diagnosis to prove biphasic differentiation such as cytokeratin showing epithelial differentiation and vimentin showing mesenchymal differentiation. Chondrosarcoma, osteosarcoma, and rhabdomyosarcoma express markers appropriate to the type of differentiation.

Heterologous differentiation may or may not be present and has no prognostic significance.[8] In the decreasing order of frequency, areas of osteosarcoma, chondrosarcoma, rhabdomyosarcoma, liposarcoma, angiosarcoma or a mixture of sarcoma histology may be seen.[8]

The exact pathogenesis of SUC is not known. The monoclonal theory states that both the carcinomatous and sarcomatous tumor cells are derived from a single pluripotent stem cell which undergoes divergent epithelial and mesenchymal differentiation.[9] The multiclonal theory states that sarcomatoid carcinoma is a collision tumor composed of the derivatives of two or more stem cells of separate epithelial and mesenchymal origin.[10] Recent molecular studies favor the former theory. Some cases may have previous history of treatment with radiotherapy or cyclophosphamide therapy.[2]

Although rare, SUC has been reported in the renal pelvis previously.[4],[5],[11],[12],[13] However, our case is rare since it is a multifocal presentation of SUC in the renal pelvis as well as the ureter, with the presence of smooth muscle differentiation (revealed on IHC).

The differential diagnosis includes true sarcoma and pseudosarcomatous mesenchymal proliferations. Mixed malignant epithelial and mesenchymal components are diagnostic and IHC for epithelial and mesenchymal markers is helpful. In the absence of obvious invasive carcinoma in a primary spindle cell tumor of the bladder, a history of prior urothelial neoplasia, coexistence of in situ disease and diffuse cytokeratin immunoreactivity would be helpful in establishing a diagnosis of sarcomatoid carcinoma over primary sarcoma.[8]

SUC should also be distinguished from sarcomatoid variant of renal cell carcinoma. Demonstration of transitional cell carcinoma component, along with proper sampling and IHC are important in the differential diagnosis.

[Table 1] describes the differential diagnosis of the case on immunocytochemistry.
Table 1: Differential diagnosis of the case on immunohistochemistry

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Further study with more cases and experience may provide great value, clinically and pathologically.

Since SUCs are rare and have an unfavorable histopathological nature, not much is known about the treatment options. They have poor prognosis despite different treatment modalities.[14]

  Conclusion Top

SUC although rare should be included in the differential diagnosis of multifocal tumors of the renal pelvis and ureter.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.

  References Top

Baschinsky DY, Chen JH, Vadmal MS, Lucas JG, Bahnson RR, Niemann TH. Carcinosarcoma of the urinary bladder–An aggressive tumor with diverse histogenesis. A clinicopathologic study of 4 cases and review of the literature. Arch Pathol Lab Med 2000;124:1172-8.  Back to cited text no. 1
Lopez-Beltran A, Pacelli A, Rothenberg HJ, Wollan PC, Zincke H, Blute ML, et al. Carcinosarcoma and sarcomatoid carcinoma of the bladder: Clinicopathological study of 41 cases. J Urol 1998;159:1497-503.  Back to cited text no. 2
Atilgan D, Parlaktas B, Uluocak N, Erdemir F. Sarcomatous carcinoma with osteosarcomatoid differentiation of the bladder with simultaneous sigmoid colon adenocarcinoma. J Surg Case Rep 2011;2011:4.  Back to cited text no. 3
Gill-Samra S, Brooks A, P'ng CH. Sarcomatoid carcinoma involving the renal pelvis and ureter with heterologous osteosarcomatous differentiation. Pathology 2012;44:367-9.  Back to cited text no. 4
Acikalin MF, Kabukcuoglu S, Can C. Sarcomatoid carcinoma of the renal pelvis with giant cell tumor-like features: Case report with immunohistochemical findings. Int J Urol 2005;12:199-203.  Back to cited text no. 5
Cheng L, Zhang S, Alexander R, Maclennan GT, Hodges KB, Harrison BT, et al. Sarcomatoid carcinoma of the urinary bladder: The final common pathway of urothelial carcinoma dedifferentiation. Am J Surg Pathol 2011;35:e34-46.  Back to cited text no. 6
Ikegami H, Iwasaki H, Ohjimi Y, Takeuchi T, Ariyoshi A, Kikuchi M. Sarcomatoid carcinoma of the urinary bladder: A clinicopathologic and immunohistochemical analysis of 14 patients. Hum Pathol 2000;31:332-40.  Back to cited text no. 7
Amin MB. Histological variants of urothelial carcinoma: Diagnostic, therapeutic and prognostic implications. Mod Pathol 2009;22 Suppl 2:S96-118.  Back to cited text no. 8
Bloxham CA, Bennett MK, Robinson MC. Bladder carcinosarcomas: Three cases with diverse histogenesis. Histopathology 1990;16:63-7.  Back to cited text no. 9
Wick MR, Swanson PE. Carcinosarcomas: Current perspectives and an historical review of nosological concepts. Semin Diagn Pathol 1993;10:118-27.  Back to cited text no. 10
Kang SG, Yoon CY, Cho JH, Yoon DK, Kim IS. Sarcomatoid carcinoma of the renal pelvis. Korean J Urol 2005;46:651-4.  Back to cited text no. 11
Paick SH, Yoon SW, Baek M, Lim SD, Lho YS, Kim HG. Sarcomatoid urothelial carcinoma of the renal pelvis with extremely aggressive clinical behaviour. Korean J Urol 2009;50:812-5.  Back to cited text no. 12
Ahn HI, Sim J, Han H, Kim H, Yi K, Jun YJ, et al. A case report of a sarcomatoid urothelial carcinoma arising in the renal pelvis with exuberant osteosarcomatous element. Open J Pathol 2013;3:96-8.  Back to cited text no. 13
Dahm P, Gschwend JE. Malignant non-urothelial neoplasms of the urinary bladder: A review. Eur Urol 2003;44:672-81.  Back to cited text no. 14


  [Figure 1], [Figure 2], [Figure 3], [Figure 4]

  [Table 1]


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