Chromophobe Renal Cell Carcinoma with Osseous

Jpn J Clin Oncol 2000;30(2)101–104

Case Reports

Chromophobe Renal Cell Carcinoma with Osseous Metaplasia: a Case Report Hiroshi Yokozaki1, Rinzo Ukai2,EisoKawashita2, Hiroshi Ikeda2, Hiroki Kuniyasu1 and Eiichi Tahara1

1First Department of Pathology, Hiroshima University School of Medicine and 2Department of Urology, Hiroshima General Hospital of West Japan Railway Company, Hiroshima, Japan

Received September 16, 1999; accepted October 29, 1999

A 60-year-old Japanese male with a chromophobe cell carcinoma of his left kidney is reported. The tumor, 18 × 27 mm in size, was incidentally found by abdominal ultrasonography. Com- puted tomography and magnetic resonance imaging demonstrated a well-demarcated solid tumor arising from the lower pole of the left kidney. Histopathological examination of the surgi- cally removed tumor revealed that it was composed of solid sheets of cancer cells having abundant and slightly eosinophilic reticular cytoplasm with accentuated cell membranes making up a plant cell-like appearance. Electron microscopic examination demonstrated numerous intracytoplasmic microvesicles. Although the tumor cells were positive for cytokeratin and epithelial membrane antigen, they did not show vimentin immunoreactivity. The unique histological finding of this tumor from other reported renal chromophobe carcinomas was that it had a peripheral fibrotic area with a focus of metaplastic ossification.

Key words: renal cell carcinoma – chromophobe cell carcinoma – ossification – immunohistochemistry –electronmicroscopy

INTRODUCTION cytoplasmic microvesicles seen by electron microscopy. Genetically, it is characterized by a combination of loss of The updated WHO histological classification offers a subdivi- heterozygosity at chromosomes 1, 2, 6, 10, 13, 17 and 21 (4). sion of renal cell carcinoma (RCC) by both their morpho- Ultrastructural and immunohistochemical characterization logical and cytogenetic features into clear cell, granular cell, have demonstrated the close phenotypic similarity between chromophobe cell, spindle cell, cyst-associated, papillary and chromophobe RCC and intercalated cells of the renal collecting-duct carcinomas (1). Chromophobe cell carcinoma collecting duct (5,6). Here we present a case of chromophobe of the kidney is a recently recognized category of human RCC RCC with osseous metaplasia within the tumor tissue. (2) that was initially described in nitrosomorpholine-induced experimental rat RCC by Bannasch et al. (3). At present, chromophobe RCC may account for about 5% of all cases of CASE REPORT RCC. Cancer cells of this distinct type of RCC display a characteristic weak and cloudy cytoplasmic staining pattern CLINICAL SUMMARY imparting a reticular appearance with conventional hematoxylin and eosin stain, corresponding to a variable number of A physician incidentally found a tumor of the left kidney in a 60-year-old Japanese male by abdominal ultrasonography in the course of a routine check-up. Computed tomography (CT) and magnetic resonance imaging demonstrated a well-demarcated, solid tumor arising from the lower pole of the left kidney For reprints and all correspondence: Hiroshi Yokozaki, First Department of (Fig. 1). The tumor was subsequently removed by partial Pathology, Hiroshima University School of Medicine, 1–2–3 Kasumi, Minami-ku, Hiroshima 734-8551, Japan. nephrectomy at the Department of Urology, Hiroshima E-mail: [email protected] General Hospital of West Japan Railway Company. The patient has been followed up for 2 years by abdominal Abbreviations: RCC, renal cell carcinoma; CT, computed tomography; PAS, periodic acid–Schiff; AB, alcian blue; EMA, epithelial membrane antigen; CT taken every 3 months after the surgery without any H&E, hematoxylin and eosin evidence of tumor recurrence or metastasis.

acid–Schiff (PAS) staining demonstrated a fine and delicate reaction to glycogen in comparison with heavy deposits observed in ordinary clear cell carcinomas (not shown). The cytoplasm of the tumor cells revealed a diffuse positive reaction with Hale’s colloidal iron stain (Fig. 2c), which is a diagnostic feature for chromophobe RCC (2). The peripheral part of the tumor underwent sclerotic fibrosis and focal osseous metaplasia was found (Fig. 2d). The tumor cells revealed a positive immunoreaction to EMA and cytokeratin, while vimentin immunoreactivity was exclusively negative throughout the tumor. Electron microscopy of the tumor cell revealed numerous microvesicles within the cytoplasm (not shown). These vesicles, round to oval in shape, were 200–400 nm in diameter and had a tendency to be concentrated adjacent to and surrounding the nucleus.

DISCUSSION Although limited data are available regarding the clinical behavior of chromophobe RCC, it has been suggested that this distinctive type of RCC has a relatively low malignant potential compared with common type RCC (8,9). Histopatho- logical characteristics of chromophobe RCC are a nesting arrangement of the tumor cells with sharply defined borders (plant-like appearance) and abundant pale acidophilic reticular cytoplasm (2). Since the initial report by Thoenes et al. (2), positive cytoplasmic reaction to Hale’s collodal iron stain has been considered to be a diagnostic feature for chromophobe Figure 1. Medical imaging of the renal tumor. (a) Coronal images on dynamic RCC and has been used as a discriminatory feature to differen- magnetic resonance imaging reveal a well-defined, solid tumor arising from tiate it from other renal tumors. However, it is noted that other the lower pole of the left kidney with inhomogeneous enhancement. (b) Plain subtypes of renal cancer also show positive reaction to this computed tomography shows a small calculus within the tumor. method with different staining patterns in comparison with that described for chromophobe RCCs. Tickoo et al. (10) empha- sized that the diffuse and strong reticular cytoplasmic stain PATHOLOGICAL FINDINGS with Hale’s method, as was observed in tumor cells in the present case, was highly characteristic of chromophobe RCC. The resected tumor, measuring 18 × 27 mm, was well circum- The presence of variable numbers of intracytoplasmic micro- scribed with a fibrous capsule. The cut surface of the tumor vesicles is an important electron microscopic feature of this was brownish tan with focal hemorrhage. Necrotic area was type of RCC (2). Bonsib and Lager (9) and Akhtar et al. (11) not observed. Paraffin sections from formalin-fixed material suggested that these microvesicles may be derived from the were stained with hematoxylin and eosin, periodic acid–Schiff outer membranes of mitochondria through extensive (PAS), alcian blue (AB) and Hale’s colloidal iron. Immuno- ultrastructural study. However, Tickoo et al. (12) could not histochemical examination was undertaken using Vectastain observe coarse granular cytoplasmic staining by antimitochon- avidin–biotin peroxidase complex kit (Vector, Burlingame, drial antibody 113–1, that recognizes a 60 kDa non-glyco- CA) and specific monoclonal antibodies against epithelial sylated protein component of mitochondria, in typical membrane antigen (EMA) (Clone GP1.4), cytokeratin (Clone chromophobe RCC. Tumor cells of chromophobe RCC present 5D3 and LP34) and vimentin (Clone VIM3B4) as described negative vimentin immunoreactivity, while demonstrating elsewhere (7). Antibodies were purchased from Novocastra positive immunoreaction to cytokeratin and EMA, as was (Newcastle upon Tyne, UK). Histologically, the tumor was observed with the present tumor (13). This is also one of the composed of solid cell sheets surrounded by delicate stroma characteristic phenotypes of chromophobe RCC for distinction containing capillaries (Fig. 2a). The tumor cells had abundant from common-type RCCs. From these morphological observa- and cloudy cytoplasm imparting a reticular appearance with tions, we concluded that the present tumor was compatible accentuated cell membranes making up a plant cell-like with typical chromophobe RCC (8). appearance. The nuclei were slightly pleomorphic with The unique histopathological finding of the present chromo- coarsely granular chromatin and occasional prominent nucleoli phobe RCC is a focus of bone formation within the tumor. conforming to a grade 2 nuclear atypia (Fig. 2b). Periodic Daniel et al. (14) reported that 10.3% (58/580) of renal cell Jpn J Clin Oncol 2000;30(2) 103

Figure 2. Histopathological findings of the tumor resected from the left kidney. (a) The tumor was composed of solid cell sheets with delicate stroma containing capillaries. H&E stain (×27). (b) Tumor cells have abundant reticular cytoplasm with accentuated cell membranes making up a plant cell-like appearance. H&E stain (×131). (c) Cancer cells reveal diffuse positive staining with Hale’s colloidal iron stain (×131). (d) Small foci of osseous metaplasia are found at the peripheral sclerotic area of the tumor. H&E stain (×68). carcinomas had calcified foci through a roentogenographic Acknowledgments review of 2709 renal masses at the Mayo Clinic. Moreover, WearegratefultoMsH.Ukai,MrT.Habara,MsM.Yasuhara reports on osseous metaplasia or bone formation within RCC with histopathological confirmation are rare (15,16). Although and Mr T. Shimizu (Department of Pathology, Hiroshima Akhtar et al. (11) described two cases of chromophobe RCC General Hospital of West Japan Railway Company) for their with radiologically validated calcification, substantially this is skillful histopathological preparations. We are also indebted to the first report on chromophobe RCC with histologically Mr M. Takatani (First Department of Pathology, Hiroshima proven ossification. Because the ossified focus in the present University School of Medicine) for his excellent technical case was found within the fibrotic area of the tumor apart from assistance with electron microscopy. We thank Dr T. Iwamoto cancer cell nests, stromal osseous metaplasia could be the best (Miyoshi Central Hospital) for valuable suggestions and explanation for the histogenesis (17). discussions. Part of this case report was presented at the 38th Recent advances in cytogenetic and molecular biological Hiroshima Assembly of Pathologists (May 22, 1999). analysis have disclosed the genetic background of each subtype of RCC (18). Speicher et al. (4) reported specific loss References of chromosomes 1, 2, 6, 10, 13, 17 and 21 in chromophobe RCC by a comparative genomic hybridization method. On the 1. Mostofi FK, Davis CJ. Histological Typing of Kidney Tumours. World other hand, common-type RCCs are genetically separated from Health Organization International Histological Classification of Tumours, 2nd ed. Berlin: Springer 1997. others based on the occurrence of a highly specific deletion of 2. Thoenes W, Störkel S, Rumpelt H-J. Human chromophobe cell renal car- chromosome 3p (19) with mutation of VHL gene (20). cinoma. Virchows Arch B 1985;48:207–17. Combination of histopathological examination and molecular 3. Bannasch P, Schacht U, Storch E. Morphogenese und Mikromorphologie cytogenetic analysis as was proposed by Bugert and Kovacs epithelialer Nirentumoren bei Nitrosomorpholin-vergifteten Ratten. I. Induktion und Histologie der Tumoren. Z Krebsforsch 1974;81:311–31. (21) may improve the accuracy of diagnosis of RCCs 4. Speicher MR, Schoell B, du Manoir S, Schröck E, Ried T, Cremer T, et al. according to the new WHO classification in the near future. Specific loss of chromosomes 1, 2, 6, 10, 13, 17 and 21 in chromophobe 104 Chromophobe renal cell carcinoma

renal cell carcinomas revealed by comparative genomic hybridization. Am 13. Pitz S, Moll R, Störkel S, Thoenes W. Expression of intermediate filament J Pathol 1994;145:356–64. proteins in subtypes of renal cell carcinomas and in renal oncocytomas. Dis- 5. Störkel S, Steart PV, Drenckhahn D, Thoenes W. The human chromo- tinction of two classes of renal cell tumors. Lab Invest 1987;56:642–53. phobe cell renal carcinoma: its probable relation to intercalated cells of the 14. Daniel WW Jr, Hartman GW, Witten DM, Farrow GM, Kelalis PP. Calci- collecting duct. Virchows Arch B 1989;56:237–45. fied renal masses. A review of ten years experience at Mayo Clinic. Radi- 6. Füzesi L, Cober M, Mittermayer CH. Collecting duct carcinoma. Cyto- ology 1972;103:503–8. genetic characterization. Histopathology 1992;21:155–60. 15. Haddad FS, Shah IA, Manné RK, Costantino JM, Somsin AA. Renal cell 7. Yokozaki H, Kyo E, Ochial A, Ito M, Ito H, Tabuchi J, et al. A mono- carcinoma insulated in the renal capsule with calcification and ossifica- clonal antibody capable of detecting new differentiation antigen of the tion. Urol Int 1993;51:97–101. stomach. Int J Cancer 1992;50:523–7. 16. Hamid Y, Poller DN. Spontaneous regression of renal cell carcinoma: a 8. Thoenes W, Störkel S, Rumpelt H-J, Moll RT, Baum HP, Werner S. pitfall in diagnosis of renal lesions. J Clin Pathol 1998;51:334–6. Chromophobe cell renal carcinoma and its variants – a report on 32 cases. 17. Olsen S. Tumours of the Kidney and Urinary Tract. Copenhagen: Munks- J Pathol 1988;155:277–87. gaad 1984. 9. Bonsib SM, Lager DJ. Chromophobe cell carcinoma: analysis of five 18. Kovacs G, Akhtar M, Beckwith BJ, Bugert P, Cooper CS, Delahunt B, et cases. Am J Surg Pathol 1990;14:260–7. al. The Heidelberg classification of renal cell tumors. J Pathol 10. Tickoo SK, Amin MB, Zarbo RJ. Colloidal iron staining in renal epithelial 1997;183:131–3. neoplasms, including chromophobe renal cell carcinoma. Emphasis on 19. Kovacs G, Wilkens L, Papp T, DeRiese W. Differentiation between pap- technique and patterns of staining. Am J Surg Pathol 1998;22:419–24. illary and nonpapillary renal cell carcinomas by DNA analysis. JNatl 11. Akhtar M, Kardar H, Linjawi T, McClintock J, Ali MA. Chromophobe Cancer Inst 1989;81:527–30. cell carcinoma of the kidney. A clinicopathological study of 21 cases. Am 20.GnarraJR,ToryK,WengY,SchmidtL,WeiMH,LiH,etal.Mutationof J Surg Pathol 1995;19:1245–56. the VHL tumor suppressor gene in renal carcinoma. Nature Genet 12. Tickoo SK, Amin MB, Linden MD, Lee MW, Zarbo RJ. Antimitochon- 1994;7:85–90. drial antibody (113–1) in the differential diagnosis of granular renal cell 21. Bugert P, Kovacs G. Molecular differential diagnosis of renal cell carcino- tumors. Am J Surg Pathol 1997;21:922–30. mas by microsatellite analysis. Am J Pathol 1996;149:2081–8.