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Introduction
Renal pelvic carcinosarcoma (RPCS) is rare in clinic, and difficult to make preoperative diagnosis. One patient diagnosed as RPCS was treated in our hospital in August 2008. We made it as a case report as follows.
Case Report
A 63-year-old man was admitted to our hospital on August 17, 2008, because of a 7-month, whole-range gross hematuria which was discontinuous and painless. Before hospitalization, the patient had been treated based on a misdiagnosis of renal calculus. The result of physical examination indicated that there was a sensitive reaction to the percussion at right renal region, without other positive signs in the body. Type-B ultrasonic examination and CT scanning showed that there was a 5.0 cm × 3.0 cm occupying lesion with a substantial texture in the right renal pelvis, and the values of the plain scan and enhancement scanning were 37.8 Hu and 54.59 Hu, respectively in CT examination on the tumor (Fig. 1). The result of preoperative diagnosis was carcinoma in the right renal pelvis. Excision of the right kidney, total length of the ureter and partial cystectomy were conducted. During the operation, an intact perirenal fascia was seen, and no infiltrated adipose capsule or obviously abnormal ureter was found. The surgical procedure was smooth and no apparent lymphadenectasis was found in the surgical field. The renal pelvis was full of yellow neoplasm which looked like fish flesh in the specimen. Pathologic examination revealed that part of the tumor tissues presented an alveolar arrangement seen under the light microscope, and the cells were polygonal, inequable sizes, more karyomitotic figures and obvious heteromorphism. In some part of the tumor, the cells were fusiform, and the heteromorphism was manifest. There was overlapping of the 2 independent parts distributed in the tumor. The result of immunohistochemical staining showed Keration (+) and Vimentin (+) (Fig. 2). The pathological examination affirmed that it was a carcinosarcoma at right renal pelvis. No apparent signs of distant metastasis were found during a 2-month follow up after the surgery.
The filling defect signs of right renal pelvis in enhanced CT scan.
The fusiform cells Vimentin (+) were seen in immunohistochemical staining.
Discussion
As a term of the diagnostics, carcinosarcoma was initially put forward by Virchow in 1864[1]. Based on the current definition of the WHO, the term means that it is a complex malignant neoplasm composed of malignant epithelial and heterologous malignant mesenchymal. The carcinosarcoma was frequently found in the upper respiratory tract and upper gastrointestinal tract, and was rarely seen in the urogenital system in which the most common sites of the tumor were urinary bladder and caput penis. The incidence rate of the carcinosarcoma in the urogenital system accounted for less than 3% of all malignant tumors of urogenital system[2]. RPCS was rare. Up to now there were only case reports in previous literature. A total of 5 cases have been reported in China[3-7].
The carcinosarcoma of the urinary system is classified into 3 types of tissue: i) tumors with an origin of epithelial tissue. There exists 2 modes of differentiated cells, i.e., epithelium and mesenchyma; ii) tumors with the malignant compositions including those from the origin of epithelial tissue and from that of the mesenchymal tissue; iii) tumors mainly composed of a malignant composition of epithelial origin and concurrently accompanied by a mesenchymal composition of malignant transformation[8]. The latter 2 types were called real carcinosarcoma, and the former 1 was customarily called sarcomatoid carcinoma. In our study, the case was the real carcinosarcoma.
Concerning the source of the disease, there are several viewpoints as follows: i) Theory of embryonal rest: the tumor originated from remaining intra-organic embryonic tissues; ii) Theory of collision: a primary carcinoma and a sarcoma adjoin each other and come across in their infiltration and progression; iii) Multiclonal theory: there is the concurrent onset of a carcinoma and a sarcoma which have different sources of the cells; iv) Theory of mesenchymal induction: in the tumor, canceration of either epithelium or mesenchyma may induce or stimulate the development of hyperblastosis in another composition, resulting in a heteromorphosis or canceration; v) Theory of totipotential stem cell (TSC) (monoclonal theory): as the entirely undifferentiated cells of multiple-differentiation potentials form tumor, they usually have many compositions of various blastoderms. In some tumors, carcinoma and sarcoma are the outcome of a TSC differentiation towards the epithelium and mesenchyma by the effect of carcinogenic factor[1,9]. With the development in the technology of molecular biology, it was shown by masses of proofs that the theory of TSC is the foundation of carcino-sarcomagenesis. At present, monoclonal theory has obtained more and more support from the authors and scholars.
Since the disease is rare in clinic, final clinical diagnosis mainly relies on some kinds of technology, such as postoperative histopathology, immunohistochemistry and electron microscopy, etc. It can be seen under the light microscope that the tumor tissues are composed of 2 compositions, i.e., carcinoma and sarcoma, with independent and overlapping distributions. The test of immunohistochemical staining can discriminate the constituents of the carcinoma and sarcoma, which is an important value to the diagnosis. A positive expression of the epithelial tissue marker Keratinor or EMA are expected to occur in the cancerous composition. The expression of the mesenchymal tissue marker Vimentin or muscular differentiation markers Actin and Desmin, and the osseous differentiation marker Osteonectin, etc., would be positive in the sarcomatous tissue. It is usually considered if both the epithelial and mesenchymal tissue markers are expressed in 2 or several malignant compositions of the same specimen, a final diagnosis of carcinosarcoma can be made[5].
It is necessary to distinguish the RPCS from sarcomatoid-carcinoma of the renal pelvis. The nature of sarcomatoid-carcinoma is carcinoma. However, this tumor presents a sarcomatoid change in the form. Immunohistochemical labeling reveals its character of the epithelial tumor, nevertheless, carcinosarcoma concurrently has 2 components, i.e. the carcinoma and sarcoma, and there is no transitional limit between the 2 compositions. Epithelial marker was shown in the carcinoma region by immunohistochemical labeling, and homologous mesenchymal marker was seen in the sarcoma region[10]. Carcinosarcoma should also be differentiated with malignant fibrous histiocytoma, pseudo-sarcomatoid granuloma, the sarcoma accompanied with pseudo-epithelial proliferation and teratoma etc.[11]
RPCS is a tumor of high malignancy. Its biological characteristics include rapid progression, rampant invasion, early infiltration and metastasis, and very poor prognosis. Long-term survivors were reported in previous literature, however, the mean survival time of these patients was less than 1 year. Based on the reports of some cases in China, most of the patients died of cancer metastasis which occurred 1 or half a year after the treatment. There were very few reports on the long-term survivors with RPCS, suggesting that there was an early hematogenous metastasis in this disease[5,6]. After 2 months of follow up, no obvious signs of recurrence and metastasis were found in the case, nevertheless, further close observation is still needed. In view of the above characteristics, radical excision should rank first in treating the disease, and early discovery, early diagnosis and early radical excision would be the optimal method in the treatment of RPCS.
- Received May 30, 2009.
- Accepted July 27, 2009.
- Copyright © 2009 by Tianjin Medical University Cancer Institute & Hospital and Springer
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