Collecting duct carcinoma with acquired cystic disease of the kidney in a long-term hemodialysis patient

Abstract:   We report a very rare case of collecting or Bellini duct carcinoma (CDC) found in a 60-year-old male who had received hemodialysis therapy for 21 years. Screening with ultrasonography revealed a solid tumor originating from the cyst wall in the right kidney with acquired cystic disease of the kidney. Subsequent computed tomography (CT) and angiography could not detect another renal tumor. Right radical nephrectomy was performed. The tumor detected preoperatively was composed of papillary renal cell tumor (RCC) and multiple clear cell carcinoma, pathologically. In addition to the tumors, CDC was revealed in the central medulla with the involvement of regional lymph nodes. Three months later, left nephrectomy was performed because left RCC was suspected during CT. The histological diagnosis was multiple clear cell carcinomas. Peritonitis carcinomatosa appeared and the patient died 13 months later.     

Renal oncocytosis: a morphologic study of fourteen cases.

Diffuse renal involvement by numerous oncocytic nodules has rarely been described. We report 14 cases (19 specimens) with innumerable oncocytic nodules in the kidney. Invariably, these kidneys showed additional associated findings. We suggest the term renal oncocytosis for this entire morphologic spectrum. Six (43%) cases had histologically or radiologically proven bilateral involvement. Each specimen had at least one dominant tumor (2.0-10.5 cm) in addition to numerous other microscopic to macroscopic oncocytic nodules. Additional features observed were: interstitial pattern, with the oncocytic tubules and acini diffusely intermingling with and infiltrating between non-neoplastic parenchyma (one case); diffuse oncocytic change in the nonneoplastic tubules, cytologically difficult to separate from the oncocytic nodules (seven cases); and benign oncocytic cortical cysts (four cases). The dominant mass in 13 specimens was a renal oncocytoma and in two, a chromophobe renal cell carcinoma. In four specimens, the largest tumor was considered a hybrid tumor because of the presence of mixed histologic features of both tumor types. Most smaller nodules had the morphologic features of renal oncocytoma, but a few had the appearance of chromophobe renal cell carcinoma or nodules with hybrid features. We conclude that the presence of numerous oncocytic nodules may be associated with a wide spectrum of oncocytic changes in the kidney. The association of numerous renal oncocytoma-like nodules with lesions having a mixed morphology or a morphology of pure chromophobe renal cell carcinoma suggests that they may constitute a morphologic spectrum of oncocytic tumors and that renal oncocytoma and chromophobe renal cell carcinoma may arise from a common progenitor lesion.     

Effect of papillary and chromophobe cell type on disease-free survival after nephrectomy for renal cell carcinoma

Background The clinical staging of renal cortical tumors traditionally has not evaluated the potential effect of histological subtypes on survival. Evidence suggests that conventional clear cell renal cell carcinoma (RCC) and nonconventional clear cell RCC (chromophobe and papillary) have different metastatic potential. Using a large renal tumor database, we examined the effect of tumor histology on the pattern of metastasis and patient survival. Methods All patients with nonmetastatic renal cortical tumors undergoing partial or radical nephrectomy were identified from a renal tumor database between July 1989 and July 2002. Kaplan-Meier and Cox regression tests were used for statistical analysis. Results Analysis revealed 1057 patients: 794 with conventional clear cell RCC, 157 with papillary RCC, and 106 with chromophobe RCC. Metastasis occurred in 95 conventional clear cell RCC, 9 papillary RCC, and 6 chromophobe RCC. Metastasis occurred in 95 conventional clear cell RCC, 9 papillary RCC, and 6 chromophobe RCC with a median follow-up of 34.6, 43.0, and 33.2 months, respectively. Using log-rank analysis, chromophobe and papillary RCC were associated with an improved disease-free survival at 5 years (P=.009 and .015, respectively). Multivariate analysis revealed tumor size, stage, and chromophobe histology as significant variables for disease progression. Conclusions Renal cortical tumors have distinct histological subtypes with varying degrees of metastatic potential. Conventional clear cell RCC, which comprises two thirds of renal cortical tumors presenting with localized disease, has a less favorable outcome when compared with papillary and chromophobe RCC. Controlling for size and stage, chromophobe, and not papillary, RCC was a significant variable for disease progression compared with conventional clear cell RCC. Knowledge of renal cortical tumor histological subtype is critical for projecting prognosis, tailoring follow-up strategies, and designing clinical trials. Presented at the 56th Annual Cancer Symposium, Society of Surgical Oncology, San Diego, CA, March 5–9, 2003.     

A case of bilateral renal cell carcinoma showing a rapid course of death in a long-term hemodialysis patient due to polycystic kidney

A case of bilateral renal cell carcinoma in a 42-year-old polycystic kidney male is reported. He had been treated with hemodialysis for 22 years. An abnormal small mass was found in one of the left renal cystic lesions by screening ultrasonography and CT scan at the 19th year of the hemodialysis. Left radical nephrectomy was performed and the histological diagnosis was a renal cell carcinoma (RCC). There was no evidence of recurrence and metastasis, however, he presented with asymptomatic macrohematuria two years after the operation. CT scan demonstrated the rapidly progressing right renal tumor and multiple para-aortic lymph node swelling. Right nephrectomy and lymphadenectomy were performed and pathological examination showed the advanced RCC with multiple lymph node metastasis. Eleven months after the second operation followed by interferon therapy. he died of multiorgan metastasis of the RCC. This is the first bilateral RCC case in polycystic kidney patient treated with hemodialysis in Japan.     

Renal cell carcinomas arising from the allograft and bilateral native kidneys

Abstract:   We present the case of a young lady who developed renal cell carcinomas (RCC) in the allograft and bilateral native kidneys metachronously within one year. She received a living donor kidney transplantation from her father. A solid tumor of 4 cm in diameter was uncovered first in the allograft kidney 103 months after transplantation, and was treated with graftectomy. Six months after graftectomy, a right renal tumor measuring 3.5 cm and left renal tumors emerged in the native kidneys. She underwent laparoscopic right and left radical nephrectomy in separate sessions. The pathological diagnosis in the allograft and right renal tumors was clear cell RCC with eosinophilic cytoplasm and that in the left kidney was clear cell carcinoma. Fluorescence in situ hybridization and human leukocyte antigen typing showed that each tumor was most probably primary disease. She was free of disease 18 months postoperatively. This is the first report on RCC arising both in the allograft and bilateral native kidneys.     

Chromophobe cell renal carcinoma with acquired cystic disease of the kidney in a long-term hemodialysis patient

We report a rare case of chromophobe cell renal carcinoma found in a 52-year-old female who had received hemodialysis therapy for 13 years. She was diagnosed as having a left renal tumor 7.5 cm in diameter with acquired cystic disease of the kidney (ACDK) by ultrasonographic examination during periodical systemic screening. As abdominal computed tomography scanning and enhanced color Doppler ultrasonography suspected that the hypervascular tumor was renal cell carcinoma, she underwent translumbar nephrectomy in July 2000. The histopathological diagnosis was chromophobe cell carcinoma with pT2 and grade 2 malignancy. Chromophobe cell carcinoma is uncommon among renal tumors with ACDK found in long-term hemodialysis patients.     

A case of renal mucinous tubular and spindle cell carcinoma

A 33-year-old man was hospitalized for treatment of a left renal tumor. The radiological findings were consistent with those of a left renal cell carcinoma (RCC). Subsequently, a radical nephrectomy was carried out. Macroscopic examination showed that a well-demarcated tumor measuring 2.9 × 2.6 × 2.5 cm was present in the middle portion of the resected kidney. The cut surface of the tumor was grayish-white in color. Pathological examination of the resected specimen showed a mucinous tubular and spindle cell carcinoma of the kidney (MTSCC-K). MTSCC-K is a low-grade renal epithelial neoplasm that has recently been recognized as a specific entity in the World Health Organization 2004 classification of RCC. To our knowledge, 17 cases of MTSCC-K in Japan have been reported by Japanese investigators. To avoid administration of excessive adjuvant treatment to patients, pathologists and urologists should consider this newly recognized low-grade malignancy when diagnosing renal tumors.     

KIT and RCC are useful in distinguishing chromophobe renal cell carcinoma from the granular variant of clear cell renal cell carcinoma

The distinction between chromophobe renal cell carcinoma, the granular cell variant of clear cell renal cell carcinoma, and renal oncocytoma is a common diagnostic dilemma. The usefulness of KIT, CD10, RCC, and RON in the differential diagnosis of these renal epithelial tumors was investigated. KIT was 100% positive in chromophobe renal cell carcinoma (11 of 11) and renal oncocytoma (12 of 12). The KIT staining pattern was identical in both tumor types, with cytoplasmic membrane attenuation, and fine granular cytoplasmic staining. In contrast, KIT was absent in all granular cell variants of clear cell renal cell carcinoma (0 of 6). RCC was observed in more than 80% of the granular cell variant of clear cell renal cell carcinoma (5 of 6) but was negative in all chromophobe renal cell carcinomas (0 of 11) and renal oncocytomas (0 of 12). CD10 was expressed in 100% of the granular cell variant of clear cell renal cell carcinoma (6 of 6), 72% of chromophobe renal cell carcinomas (8 of 11), and 58% of renal oncocytomas (7 of 12). RON was 100% positive in the chromophobe renal cell carcinomas (11 of 11) and renal oncocytomas (12 of 12) but only 50% positive in the granular cell variant of clear cell renal cell carcinoma (3 of 6). Colloidal iron was diffusely and strongly positive in more than 80% of the chromophobe renal cell carcinomas (9 of 11), focally and weakly positive in 41% of the renal oncocytomas (5 of 12) but negative in all granular cell variant of clear cell renal cell carcinoma (0 of 6). The above results demonstrate that: 1) KIT is a very sensitive marker for both chromophobe renal cell carcinoma and renal oncocytoma; 2) immunohistochemistry using antibodies to KIT combined with RCC was sufficient to discriminate between chromophobe renal cell carcinoma and the granular cell variant of clear cell renal cell carcinoma; and 3) neither RON, nor KIT, nor a combination of this panel can be used to distinguish chromophobe renal cell carcinoma from renal oncocytoma. Colloidal iron staining aided in this distinction for the majority of the chromophobe renal cell carcinomas (more than 80% positive) and renal oncocytomas (close to 60% negative).     

Incidentally discovered yellowish lesions in a renal graft from a deceased donor

The opening of Gerota's fascia, soon after harvesting the kidney, is a standard kidney donor procedure in Italy to exclude a renal cell carcinoma (RCC), a frequent finding in older donors. Herein we have reported our experience with the diagnosis and management of subcapsular yellow areas suggestive of RCC on the kidney surface during back-table procedures. From 2001 to 2006, 12/445 grafts showed a single yellowish subcapsular nodule during the back-table procedure which was excised for frozen section (FS) to rule out RCC. The affected donors were 7 males and 5 females of overall mean age of 60 years (range, 25-77 years). The mean nodule diameter was 0.75 cm (range, 0.3-1.2 cm), and all lesions were located in the upper renal pole. In 5 cases, a diagnosis of RCC could not be excluded by FS, and both kidneys were discarded. The final histology confirmed RCC in only 3 cases, and adrenal heterotopia (AH) in the other 2. In the remaining 7 cases, FS showed AH in 4, 1 angiomyolipoma, and 2 areas of infarction confirmed by histology. The adrenal foci consisted of clear cells and scattered cells with eosinophilic, granular cytoplasm and small round nuclei, some with small nucleoli. Immunostains for cytokeratins, CD10, and epithelial membrane antigen were negative, confirming the adrenal origin. AH is the most common pathological yellowish lesion in the upper kidney pole found incidentally during back-table preparation. A histological differential diagnosis with RCC at FS is difficult, relying on the distinction of normal corticoadrenal spongiocytes from Fuhrman grade 1 clear cancer cells. In Italy, for any renal mass suggestive of RCC, a graft discard is mandatory, even if several reports have described cases of renal transplantation performed after back-table excision of small unifocal tumors.     

Expression of epithelial cell adhesion molecule (EpCam) in renal epithelial tumors

EpCam is an epithelial adhesion molecule expressed in a broad range of carcinomas. Clinical trials with specific humanized anti-EpCam antibodies have shown promising results and have been inaugurated in renal cell carcinoma (RCC) therapy. To study the EpCam expression profile, primary renal cell neoplasms as well as corresponding metastases were evaluated by immunohistochemistry in tissue microarrays. EpCam expression in oncocytomas and chromophobe RCCs was determined on conventional large sections. Moderate or strong EpCam expression was found in eighteen percent of clear cell (n=147), 75% of chromophobe (n=12), and 55% of papillary RCCs (n=20), but not in oncocytomas (n=3). On large sections, 90% of chromophobe RCCs (n=20) showed a strong and homogeneous positivity, whereas oncocytomas (n=15) revealed EpCam positivity in single tumor cells or small clusters. Fourteen percent of RCC metastases (n=97) showed EpCam expression. Patients with EpCam expressing clear cell RCC showed a trend toward a better prognosis in a Cox regression analysis including stage, grade, and necrosis. The data suggest EpCam as a potential therapeutic target in a subset of patients with RCC. In addition, expression patterns of EpCam could become a helpful tool in the discrimination of chromophobe RCC and oncocytoma.     

Nephron sparing surgery for renal cell carcinoma in a solitary kidney

To determine functional and oncological outcomes of nephron sparing surgery (NSS) for renal cell carcinoma (RCC). We identified from our kidney database 103 consecutive patients undergoing NSS for solid renal tumors in a solitary kidney. After excluding 17 patients (16.5%) undergoing NSS with palliative intent in presence of preoperatively diagnosed metastatic disease (n = 15) or positive lymph nodes (n = 2) and 6 patients (5.8%) who turned out to have benign tumors, the remaining 80 patients with RCC were analyzed. Mean follow-up is 8.0 years (range: 0.1–25.8). Mean tumor size was 4.2 cm (range 1.2–11 cm). Chronic renal failure requiring hemodialysis developed after NSS in nine patients (11.2%). In the remainder, serum creatinine was 1.72 mg/dl (range: 0.45–4.6 mg/dl) at latest follow-up. The cancer specific survival rates at 1, 5 and 10 years were 97.2, 89.6 and 76%, respectively. The estimated local recurrence free survival rates at 1, 5 and 10 years were 97.8, 89.4 and 79.9%, respectively. Univariate analysis of correlation between clinical and pathologic features with death from RCC showed significant associations for grading and tumor size. The long-term data of our series support the concept of organ-sparing surgery for RCC in a solitary kidney since it provides excellent local tumor control and cancer specific survival and preserves renal function renal function so that 89% of patients remained free of dialysis in the long-run.     

CD70: a new tumor specific biomarker for renal cell carcinoma

PURPOSE: To date there have been no specific tumor markers available for the differential diagnosis of renal cell carcinoma (RCC). In an earlier study we identified high RNA expression of CD70 in clear cell RCC. CD70 is a type II transmembrane protein belonging to the tumor necrosis factor family. It represents the ligand for CD27, a glycosylated transmembrane protein of the tumor necrosis factor receptor family. To our knowledge the function of CD70 in solid tumors is not known. In the current study we analyzed CD70 protein expression in different RCC subtypes. MATERIALS AND METHODS: A total of 68 tumor samples of different histopathological subtypes were investigated by immunochemistry, including 41 clear cell, 19 papillary and 5 chromophobe RCCs, and 3 oncocytomas as well as their normal tissue counterparts. Immunochemistry was performed on frozen tissue samples using monoclonal antibody against CD70. RESULTS: None of the normal kidney tissues showed CD70 expression. In contrast, all clear cell RCCs expressed CD70 at a high level. Positive immunostaining was observed in 1 papillary (5%) and in 1 chromophobe (20%) RCC. Five papillary tumor samples (26%) showed focal staining in less than 5% of cells. All other samples were negative for CD70. CONCLUSIONS: Our study identified CD70 as a new specific tumor marker for clear cell RCC. This new marker can be used for differential diagnosis in cases of uncertain histological classification. The function of this protein in tumorigenesis and its use as a diagnostic marker in serum and urine or as a therapeutic tool must be investigated in further studies.     

长期血透患者获得性囊性肾病合并肾癌8例报告并文献复习

目的:学习长期血透患者获得性囊性肾病合并肾癌的筛查和诊治方法。方法:回顾性分析我院维持性血透获得性囊性肾病合并肾癌患者8例,均为B超和CT诊断为双肾多发性囊肿合并肾实质性占位,并行后腹腔镜下根治性肾切除术,术后维持规律性血透,并严密随访。结果:长期血透患者226例,获得性囊性肾病105例(46.5%),获得性囊性肾病合并肾癌8例(3.5%),在获得性囊性肾病中发生率为7.6%(8/105),其中男5例,女3例,年龄(58.6±16.4)岁,血透(12.2±6.9)年。8例患者(9次)行后腹腔镜下根治性肾切除术,手术均成功,出血(45.2±20.3)ml,手术时间(72.5±20.3)min,无严重手术并发症,术后病理3例为透明细胞癌和6例为乳头状癌。住院天数为(7.5±2.4)d。随访12～63个月,无瘤存活5例。结论:肾癌在获得性囊性肾病患者中发病率高,随着血透患者寿命的延长,血透3年后需重视和建立肾癌筛查机制,腹腔镜下根治性肾切除术安全有效、恢复快,并注重患者心脑血管疾病及糖尿病等并发症的积极治疗,有助于进一步延长血透患者寿命。     

An aggressive course of Xp11 translocation renal cell carcinoma in a 28-year-old man

Abstract:   Cases of renal cell carcinoma (RCC) associated with Xp11 translocations are rare and are reported predominantly in children. We report a case of a young man who developed an aggressive Xp11 translocation RCC. A 28-year-old man presented with back pain, fever and macroscopic hematuria. Computed tomography of the abdomen showed a heterogeneous mass in the left kidney. Left radical nephrectomy was performed. Hematoxylin–eosin staining revealed nested and papillary architecture, clear and eosinophilic cytoplasm and vesicles with prominent nucleoli. Immunohistochemical evaluation revealed that the tumor cells showed nuclear labeling for TFE3 protein. On the basis of these findings, the case was diagnosed as Xp11 translocation RCC. This tumor massively recurred and led to the patient's death 2 years after the initial diagnosis. The utility of immunohistochemistry using antibodies against TFE3 in RCC occurring in young adults may be necessary for accurate diagnosis.     

Angiogenesis in renal cell carcinoma: The role of tumor-associated macrophages

Objective:   To explore vascularity and associated molecules in renal cell carcinoma (RCC) and to study their correlations to disease outcome.
Methods:   Tissue samples from 51 Japanese patients with renal cell carcinoma (RCC) were obtained between November 1997 and August 2000. Pyrimidine nucleoside phosphorylase and vascular endothelial growth factor (VEGF) levels of RCC and normal kidney tissue were determined by enzyme-linked immunosorbent assay. Microvessel density (MVD) was measured by immunohistochemistry using anti-factor-VIII-related antigen and CD34. The number of infiltrating tumor-associated macrophages (TAM) was measured by immunohistochemistry using anti-CD68 antibody.
Results:   Pyrimidine nucleoside phosphorylase and VEGF levels were significantly higher in RCC than in normal kidney tissue. The VEGF level was higher in more progressive (high grade, larger or symptomatic) RCC. Although MVD as determined by the factor VIII level was higher in larger tumors, MVD determined by CD34 was higher in low-grade and low-stage tumors. Patients with symptoms, large tumor or high stage showed higher numbers of TAM. VEGF level and TAM were significantly higher in patients with recurrence than in those without recurrence. In univariate analysis, VEGF, TAM and CD34 tumor grade and stage were identified as prognostic factors. Moreover, TAM was the only independent prognostic factor by multivariate analysis. Among these parameters, only TAM and MVD as determined by factor VIII showed significant correlations.
Conclusion:   TAM and VEGF are substantially involved in tumor progression of RCC. As the TAM count is well correlated to the MVD, the main mechanism of tumor progression by TAM might be angiogenesis.     

Tuberous sclerosis, associated with renal cell carcinoma and angiomyolipoma, in a patient who developed endstage renal failure after nephrectomy

We report a case of tuberous sclerosis (TSC) associated with renal cell carcinoma and angiomyolipoma in a patient, who developed endstage renal failure that required hemodialysis after nephrectomy. A 37-year-old woman with TSC was admitted for further investigation of bilateral renal masses detected by computed tomography (CT). Angiography revealed a tumor stain (4 cm in diameter) in the medial portion of the right kidney. Because renal cell carcinoma (RCC) was strongly suspected, right nephrectomy was performed. Her serum creatinine level was already increased, moderately, at 2.4 mg/dl, before the right nephrectomy. Her renal function deteriorated quickly (in 1&frac; years) after the right nephrectomy, and hemodialysis was introduced the next year. The histological findings of the resected right kidney revealed marked intimal thickening of the intralobular arteries. These findings suggested that the renal function loss was not only caused by the nephron mass reduction due to the nephrectomy but was also caused by nephrosclerosis. Though most patients with TSC die before developing endstage renal failure, this patient is currently receiving maintenance hemodialysis and has been followed for 3 years with no recurrence of RCC in the left kidney.     

Comparisons of outcome and prognostic features among histologic subtypes of renal cell carcinoma

Our objective was to compare cancer-specific survival and to examine associations with outcome among the histologic subtypes of renal cell carcinoma (RCC). We studied 2385 patients whose first surgery between 1970 and 2000 was a radical nephrectomy for sporadic, unilateral RCC. All RCC tumors were classified following the 1997 Union Internationale Contre le Cancer and American Joint Committee on Cancer guidelines. There were 1985 (83.2%) patients with clear cell, 270 (11.3%) with papillary, 102 (4.3%) with chromophobe, 6 (0.3%) with collecting duct, 5 (0.3%) with purely sarcomatoid RCC and no underlying histologic subtype, and 17 (0.7%) with RCC, not otherwise specified. Cancer-specific survival rates at 5 years for patients with clear cell, papillary, and chromophobe RCC were 68.9%, 87.4%, and 86.7%, respectively. Patients with clear cell RCC had a poorer prognosis compared with patients with papillary and chromophobe RCC (p <0.001). This difference in outcome was observed even after stratifying by 1997 tumor stage and nuclear grade. There was no significant difference in cancer-specific survival between patients with papillary and chromophobe RCC (p = 0.918). The 1997 TNM stage, tumor size, presence of a sarcomatoid component, and nuclear grade were significantly associated with death from clear cell, papillary, and chromophobe RCC. Histologic tumor necrosis was significantly associated with death from clear cell and chromophobe RCC, but not with death from papillary RCC. Our results demonstrate that there are significant differences in outcome and associations with outcome for the different histologic subtypes of RCC, highlighting the need for accurate subtyping.     

Chromophobe renal cell carcinoma: the impact of tumor grade on outcome

It has been reported that Fuhrman grading is not appropriate for chromophobe renal cell carcinoma (RCC). The objective of this study was to determine whether nucleolar grading and the recently described chromophobe RCC grading system by Paner and colleagues provide prognostic information. Pathologic features of 185 patients with chromophobe RCC treated surgically between 1970 and 2006 were reviewed, including nucleolar grade, chromophobe RCC grade, the 2010 TNM groupings, sarcomatoid differentiation, and coagulative tumor necrosis. Cancer-specific (CS) survival was estimated using the Kaplan-Meier method, and associations with CS survival were evaluated using Cox proportional hazard regression models. Twenty-three patients died from RCC at a mean of 3.0 years after surgery (median 1.3; range 0 to 16) with estimated CS rates (95% confidence interval) of 89% (84 to 94), 86% (81 to 92), and 85% (78 to 91) at 5, 10, and 15 years after surgery. Univariate associations with CS survival included the 2010 TNM stage groupings, sarcomatoid differentiation, coagulative tumor necrosis, chromophobe RCC grade, and nucleolar grade (all P<0.001). These last 4 features remained significantly associated with CS survival after adjusting for the 2010 TNM stage groupings. When the analysis was restricted to the 155 patients with nonsarcomatoid TNM stage groupings I and II chromophobe RCC, only stage grouping (I vs. II) was significantly associated with CS survival (P=0.03). Although the chromophobe RCC grading system described by Paner and colleagues and nucleolar grade are associated with CS survival in chromophobe RCC, they add no additional prognostic information once TNM stage and sarcomatoid differentiation are assessed.     

Diagnosing primary and metastatic renal cell carcinoma: the use of the monoclonal antibody 'Renal Cell Carcinoma Marker'.

The diagnosis of primary or metastatic renal cell carcinoma (RCC) can be difficult, especially in small biopsies, because of the wide variety of histologic appearances and clinical presentations that RCC can assume. An immunomarker specific for RCC is currently not available. We tested the relevant diagnostic use of the Renal Cell Carcinoma Marker (RCC Ma), a monoclonal antibody, against a normal human proximal tubular brush border antigen. Immunostaining using RCC Ma and the avidin-biotin-peroxidase complex technique was performed on archival tissues from primary and metastatic tumors of renal or nonrenal origin. A total of 122 of 153 primary RCCs (79.7%) were positive [clear cell (84%), papillary (96%), chromophobe (45%), sarcomatoid (25%), and collecting duct (0%)], with > or =10% of tumor cells stained in 93% of cases. None of the 64 primary renal tumors other than RCC, including 15 oncocytomas, was positive. Fifteen of 146 (10.2%) nonrenal primary tumors were positive (5 of 17 breast tumors, 8 of 8 parathyroid adenomas, and 2 of 7 embryonal carcinomas). Forty-two of 63 (67%) metastatic RCCs were positive with > or =10% of cells being stained in 83% of them. Two of 108 (2%) metastases from tumors other than RCCs were positive, both of which were metastatic breast carcinomas; however, only 10% (2 of 19) of metastatic breast carcinomas were positive. RCC Ma is an excellent marker for primary RCC, which should facilitate its diagnosis in a small biopsy. Although RCC Ma remains highly specific (98%) for metastatic RCC, a negative result may not rule out metastatic RCC because of a rather low sensitivity and a focal staining pattern in some of the positive cases. RCC Ma may also facilitate the differential diagnosis between oncocytoma and other types of RCC when they are composed mostly of eosinophilic cells.     

Beta defensin-1, parvalbumin,and vimentin: a panel of diagnostic immunohistochemical markers for renal tumors derived from gene expression profiling studies using cDNA microarrays

The common histopathologic subtypes of renal epithelial neoplasms include conventional, or clear cell, renal cell carcinoma (RCC), papillary RCC, chromophobe RCC, and renal oncocytoma. These subtypes differ clinically and pathologically, making accurate classification important. However, this differential diagnosis can be challenging because of overlapping morphology, suggesting a potential utility for ancillary immunohistochemical markers. We used cDNA microarrays to identify candidate markers for distinguishing renal tumor subtypes. In this report we validated differential expression of three candidate markers, beta defensin-1, parvalbumin, and vimentin, and evaluated the use of this immunohistochemical panel as a potential diagnostic tool. Consistent with our cDNA microarray data, chromophobe RCCs and oncocytomas exhibited similar expression profiles: 8 of 8 examples of each subtype were immunohistochemically positive for beta defensin-1 and parvalbumin and negative for vimentin (sensitivity 100%, specificity 100%); 4 of 7 papillary RCCs were positive for beta defensin-1, parvalbumin, and vimentin (sensitivity 57%, specificity 97%); and 22 of 23 conventional RCCs were negative for beta defensin-1, parvalbumin, or both markers (sensitivity 96%, specificity 96%) as well as positive for vimentin (sensitivity 83%). The immunohistochemical panel distinguished renal tumor subtypes with greater specificity than any marker used alone. This work demonstrates that a useful panel of immunohistochemical markers can be derived from differential gene expression profiles determined using cDNA microarrays.