|Year : 2015 | Volume
| Issue : 4 | Page : 1027
Renal cell carcinoma, unclassified with unique features
Bal Chander1, Kamal Preet1, Ramesh Bharti2, Prabal Deb3
1 Department of Pathology, Dr. Rajendra Prasad Government Medical College, Kangra, Tanda, Himachal Pradesh, India
2 Department of Surgery, Dr. Rajendra Prasad Government Medical College, Kangra, Tanda, Himachal Pradesh, India
3 Department of Pathology, Armed Forces Medical College, Pune, Maharashtra, India
|Date of Web Publication||15-Feb-2016|
Department of Pathology, Dr. Rajendra Prasad Government Medical College, Kangra, Tanda - 176 001, Himachal Pradesh
Source of Support: None, Conflict of Interest: None
Renal cell carcinoma, unclassified constitute about 3-4% of all renal carcinomas. It essentially is a tumor where more than morphological variants or subtypes are seen in a single tumor. Usually there is a mixture of 2-3 different types. However, in this particular case there were at least 5 different types of morphological patterns in a single tumor including areas of so-called rhabdoid differentiation. The patient underwent nephrectomy and has been asymptomatic for the last 3.5. years. To the best of our knowledge, this is the first case of its own kind in the published literature.
Keywords: Renal cell carcinoma, unclassified, unique combination, unique features
|How to cite this article:|
Chander B, Preet K, Bharti R, Deb P. Renal cell carcinoma, unclassified with unique features. J Can Res Ther 2015;11:1027
| > Introduction|| |
Kidney tumors account for 2% of all human malignancies. Among these, clear cell carcinoma represents 90% of all adult renal tumors. Histologically they are composed of clear cells arranged in a solid sheet, alveolar pattern or acinar pattern. Some tumors may be partly or completely cystic. Sarcomatoid change is seen in 5% of cases and is a bad prognostic factor. Renal cell carcinoma (RCC), unclassified accounts for 4-5% of renal tumors., We report a case of renal tumor where a myriad of histological patterns were seen which did not readily fit into any of the other categories and hence reported as RCC, unclassified.
| > Case Report|| |
A 55-year-old male presented with dull left flank discomfort and pain for 3 months. Routine laboratory investigations were within normal limits. Ultrasound examination revealed a right renal mass which on computed tomography (CT) scan appeared to be confined to the upper lobe [Figure 1]. The adjacent adrenal gland was uninvolved. A radiological diagnosis of carcinoma was made, and the patient underwent radical nephrectomy. On gross examination, the tumor measured 5.5 × 4 × 3 cm and showed distinct areas of cystic change. Multiple sections examined showed varied morphology of the tumors in different areas. It would be convenient to number the patterns. (a) Most prominent components were clear cell carcinoma with abundant clear cytoplasm and grade 1 or 2 nuclei. Cystic areas were seen lined by the similar cells in addition to glandular pattern. The clear cells were diffusely positive for CD10 and showed focal positivity for vimentin. (b) The second component consisted of large highly pleomorphic cells with abundant eosinophilic cytoplasm, eccentric nuclei and the occasional mitosis. These tumor cells were positive for CD10, vimentin and nonspecific esterase. The stains for chromogranin, desmin and CK7 and MyoD1 were negative. (c) The third component consisted of tubular pattern lined by cells with a moderate amount of eosiophilic cytoplasm and mild nuclear pleomorphism. The immune profile was similar to that of clear cell component. (d) The fourth component consisted of cells arranged in sheets with oval nuclei showing moderate pleomorphism and variable cytoplasm. The cells were negative for CD10 and vimentin. (e) A few tiny foci of cells with a moderate amount of dense eosiophilic cytoplasm were also noted. In addition, there were foci of necrosis. The tumor was confined to the kidney. Sections from the hilar structures and the perirenal tissue were free of tumor [Figure 2],[Figure 3],[Figure 4].
|Figure 1: Cut section of nephrectomy specimen showing a tumor with mostly solid area along with clearly visible cysts. The tumor margins are rather ill defined|
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|Figure 2: (a) H and E, (×10) adjacent areas with rhabdoid and undifferentiated tumors. (b) H and E, (×10) adjacent areas with undifferentiated and clear cell carcinoma. (c) H and E, (×20) tumor with rhabdoid morphology. (d) H and E, (×20) clear cell tumor|
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|Figure 3: (a) H and E, (×10) undifferentiated tumor. (b) H and E, (×20) tumor cells with dense eosinophilic cytoplasm (c) H and E, (×10) tumor with distinct tubules. (d) H and E, (×20) undifferentiated tumor with necrosis|
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|Figure 4: (a) Vimentin (×10) positive in both rhabdoid and clear cell component. (b) Nonspecific esterase (×20) positive in rhabdoid but negative in clear cell component. (c and d) CD10 (×20) positive in both rhabdoid and clear cell component|
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A diagnosis of RCC unclassified was thus made.
In the light of highly unusual tumor, the patient was advised full body CT scan which did not reveal any other lesions or tumors.
The patient has been asymptomatic for the last 3.5 years despite the fact that he had not opted for chemotherapy.
| > Discussion|| |
Renal cell carcinomas are fairly common constituting about 2% of all adult cancers. It is seen more frequently in males in older age group compared with the females. Approximately, 30% of the patients present with the metastatic disease and the prognosis in such cases is generally not favorable. Clear cell RCC amounts for about 90% of RCCs. Remaining 10% can be classified as one of the well-defined entities. However, about 4-5% of the tumors cannot be fitted into any of the well-defined diagnostic categories on the basis of morphological patterns and thus they come under the rubric of RCC, unclassified. Included in this category are the tumors, which are composite of more than one type of well-recognized renal tumors, sarcomatoid morphology without recognizable epithelial component, mucin production, mixture of epithelial and stromal elements, and unrecognized cell types.
There are a few unique features of this tumor. There is clear cell component but with different patterns of the same. Areas of macro cystic change are seen even grossly in addition to the normal clear cell tumor. There are areas of tubule formation lined by cells with minimal to a moderate cytoplasm which may qualify as mucinous tubular and cystic tumor. The adjacent area with tumor composed of highly anaplastic cells many of which are bizarre forms the most striking part and the region where tumor is composed of sheets of cells vaguely simulating transitional cell carcinoma is also no less striking. All these different types occupy well-defined areas and we do not see any intermixing of different patterns. It is as if during tumorogenesis, very early on, different cells began to differentiate along varied morphology and pattern. The fact that all the different patterns show positivity for CD10 favors the conclusion that it is indeed a single tumor with uniquely varied morphology even as it is a bit difficult to reconcile many patterns in a single tumor.
The key question, particularly in view of highly anaplastic tumor component is: How should it be prognosticated. The common sense would dictate that the prognosis should be dictated by the most aggressive or aggressive looking component which in this case should be areas with rhabdoid morphology. Indeed Leroy et al. demonstrated that the rhabdoid component expresses higher expression of p53 and is associated with poor prognosis. The rhabdoid change or differentiation has been considered to a type of sarcomatoid change as a consequence of dedifferentiation by Chapman-Fredriks.
The purpose of the present article is to highlight hitherto undocumented unique “composite tumor.” Theoretically, all the tumors benign or malignant can show dedifferentiation. The rarity of the tumor like the one being presented can perhaps be explained by the fact that generally pathologists examine only a tiny two-dimensional fraction of the tumor. From a tumor such as this one with an approximate volume of 38 cm 3 total of 10 sections were taken with an average thickness of 3 µm amounting to a mere 0.04 cm 3 which is just 0.1% of the total tumor evaluated. We recommend that RCCs such as this one or any other tumor with divergent differentiation ought to be studied in detail since these are potential repository of basic information pertaining to the process of dedifferentiation.
| > References|| |
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[Figure 1], [Figure 2], [Figure 3], [Figure 4]