Diagnostic value of imaging in patients with clear cell papillary renal cell carcinoma: A case series and literature review.

Clear cell papillary renal cell carcinoma (CCPRCC) is a newly classified renal cell carcinoma with a low degree of malignancy. Its imaging features have not been studied deeply. Therefore, we reviewed the imaging features of CCPRCC. Solid CCPRCC shows high echo or isoecho mass on conventional ultrasound. Contrast enhanced ultrasound shows "fast forward and slow backward, uneven high enhancement". Computed tomography shows high enhancement and maximum enhancement in the cortical-medullary phase. Magnetic resonance imaging shows slightly low T1WI and high T2WI. This article aims to improve the understanding of CCPRCC by clinical radiologists and promote the accurate.

Imaging Characteristics of Clear Cell Papillary Renal Cell Carcinoma: Identifying the Sheep in Wolf's Clothing.

OBJECTIVE: This study aimed to describe the characteristics of computed tomography (CT) and magnetic resonance imaging (MRI) of clear cell papillary renal cell carcinoma (CCPRCC). METHODS: This retrospective study comprised 27 patients diagnosed with 29 tumors of CCPRCC. The study was approved by the Medical Ethics Committee and the requirement for the informed consent was waived. The inclusion criteria stipulated pathology-confirmed CCPRCCs with at least one preoperative imaging examination, including CT or MRI. Two experienced radiologists independently analyzed the imaging characteristics, including size, location, growth mode, morphology, texture, density, and enhancement pattern. Paired t-test was used to compare differences in CT Hounsfield unit values and apparent diffusion coefficient (ADC) imaging between the tumor and the renal cortex. RESULTS: The mean age of the 27 patients was 57.0 ± 14.2 years. Nineteen patients underwent CT, while 12 underwent MRI (There are 4 patients underwent not only CT but also MRI). Among the cases, 26 (96%) were single, and 1 (4%) was multiple, consisting of three lesions. Out of the 29 tumors, 15 (52%) were located in the left kidney and 14 (48%) in the right kidney. The mean tumor diameter was 3.3 ± 1.7 cm. Furthermore, 19 (66%), 3 (10%), and 7 (24%) tumors were solid, cystic, mixed solid, and cystic type, respectively. The growth mode was endogenous and exogenous in 8 (28%) and 21 (72%) tumors, respectively. The tumor shape was irregular and round in 5 (17%) and 24 (83%) tumors, respectively. The CT value of the tumor was approximately 33.2 ± 9.8 HU, which was not significantly different from that of the renal cortex(31.1 ± 6.3HU)(p = 0.343). Furthermore, 7 (24%), 12 (41%), and 3 (10%) had calcification, cystic degeneration, and hemorrhage, respectively. In 12 tumors, hypointense and hyperintense were predominant on T1 and T2-weighted images, respectively. The tumor capsule was found at the edge of 12 tumors. The average ADC value of the tumor (1.54 ± 0.74 × 10-3 mm2/s) and that of the renal cortex(1.68 ± 0.63×10-3mm2 /s) was not statistically significantly different (p = 0.260). The enhancement scanning revealed "wash-in and wash-out" enhancement in 19 (68%) tumors, continuous or progressive enhancement in 6 (21%) tumors, and enhanced cystic wall and central separation in 3 (11%) tumors. CONCLUSION: CCPRCC occurs more likely in middle-aged and elderly individuals, and the tumor is prone to cystic degeneration, with rare bleeding and calcification, and no obvious limitation on MRI diffusion-weighted imaging, which enhancement form performs as mainly "wash-in and washout," but the final diagnosis depends on histopathology.

Clinicopathological features and prognosis of clear cell papillary renal cell carcinoma / 现代泌尿外科杂志

【Objective】 To investigate the clinicopathological features and prognosis of clear cell papillary renal cell carcinoma (CCPRCC). 【Methods】 The clinicopathological and follow-up data of 40 CCPRCC patients treated during Jun. 2011 and Oct.2021 were retrospectively analyzed. The prognosis was compared with that of 40 cases of clear cell renal cell carcinoma (ccRCC) and 19 cases of papillary renal cell carcinoma (PRCC) treated in the same period. Survival analysis was performed by Log-rank test and Kaplan-Meier survival curves were plotted. 【Results】 Among the 40 patients, 28 were male and 12 were female, aged 31-84 years; 38 cases had unilateral and 2 cases had bilateral tumors; 3 cases had multifocal lesions. All patients received surgery. The maximum diameter of the masses ranged from 3.0 to 95.0 mm, with an average of (27.6±18.1) mm. Pathological grade was Fuhrman 1-2 in all cases. Immunohistochemical tests were positive for CK7 and CA-IX. During the follow-up of 5-129 (average 56) months, 1 case died after bone metastasis, 2 had ipsilateral recurrence, and 1 developed primary esophageal cancer. CCPRCC patients had a significantly better prognosis than CCRCC (P<0.001) and PRCC (P=0.005) patients, while there was no significant difference in the prognosis between CCRCC and PRCC patients (P=0.93). 【Conclusions】 CCPRCC has low malignancy. The diagnosis relies on characteristic pathological and immunohistochemical features. Surgery is an effective treatment. CCPRCC has a better overall prognosis than CCRCC and PRCC.

Clinical characteristics and survival analysis of patients with clear cell papillary renal cell carcinoma based on SEER database / 现代泌尿外科杂志

【Objective】 To evaluate the clinical characteristics and survival of patients with rare clear cell papillary renal cell carcinoma (ccpRCC). 【Methods】 Clinical data of ccpRCC cases treated during 2016 and 2019 were analyzed, clinical characteristics were described, and survival was analyzed using the Kaplan-Meier method. 【Results】 In the SEER database, 191 ccpRCC cases with complete clinical data and positive histology were retrieved, including 112 males (58.7%) and 79 females (41.3%), 136 Grade 1-2 (71.2%) cases and 19 Grade 3-4 (10.0%) cases, 174 stage T1 (91.1%) cases and 17 stage T2-3 (8.9%) cases. Distant metastasis (lung metastasis combined with lymph node involvement and major vein involvement) occurred in one case, and vein tumor thrombosis occurred in two patients. Surgery especially radical nephrectomy and partial nephrectomy was performed in 181 patients (94.8%). One patient died due to recurrence, and 4 due to other causes. The 12-month and 24-month survival were 98.5% and 97.4%, respectively. 【Conclusion】 Patients with ccpRCC have low clinical stage and histological grade, minimal tumor progression and distant metastasis, good prognosis and extremely low disease-specific mortality. Radical nephrectomy and partial nephrectomy have significant therapeutic effects.

Papillary renal neoplasm with reverse polarity-a comparative study with CCPRCC, OPRCC, and PRCC1.

Papillary renal neoplasm with reverse polarity (PRNRP) is a newly defined entity with distinct histomorphology and recurrent KRAS mutation. In this study, we aimed to identify and analyze the clinicopathological, immunohistochemical (IHC), and molecular features of PRNRP in our center and to evaluate its differential diagnosis with other tumors with which it is easily confused: clear cell papillary renal cell carcinoma (CCPRCC), oncocytic papillary renal cell carcinoma (OPRCC), and papillary renal cell carcinoma type 1 (PRCC1). Nephrectomy specimens of PRNRP (n = 15), CCPRCC (n = 11), and OPRCC (n = 12) were retrieved from our pathology archives. We also selected typical cases of PRCC1 (n = 15) as a control group. PRNRP accounted for 3.05% (15/492) of all PRCC cases at our center. The median follow-up period was 41.3 months. All PRNRP cases were pT1N0M0, and only one involved recurrence (1 year after surgery). IHC analysis showed diffuse staining of CK7, EMA, and GATA3 but weak or negative staining of CD10, CD117, p504s, and vimentin in the PRNRP samples and distinctive IHC features in the other three tumor types. KRAS mutation was detected in 4/10 PRNRP cases. Among the 40 most commonly mutated genes identified, 5 (BCLAF1, PDE4DIP, NCOR1, PARP4, and PABPC1) have actionable alterations. Our study supports the suggestion that PRNRP is an entity distinct from CCPRCC, OPRCC, and PRCC1.

Renal Cell Carcinoma in End-Stage Renal Disease: A Review and Update.

Renal cell carcinoma (RCC) occurring in the setting of end-stage renal disease (ESRD) shows unique clinicopathological characteristics. The two most frequent types of ESRD-associated RCC are acquired cystic kidney disease-associated renal cell carcinoma (ACKD-RCC) and clear-cell papillary renal cell carcinoma (ccpRCC). Other types of RCC also occur in ESRD, albeit with different frequencies from the non-ESRD general population. The histological features of RCC do not vary in the setting of ESRD vs. non-ESRD, yet other findings, such as multifocality and multiple tumor types, are more frequent in ESRD. Studies have generated novel and important knowledge of the etiology, epidemiology, diagnosis, treatment, immunophenotype, and molecular characteristics of ESRD-associated RCC. Knowledge of these data is important for both pathologists and other physicians who may encounter ESRD patients with RCC. This review presents a comprehensive summary and update of the literature on RCC in ESRD, with a focus on the two most frequent types, ACKD-RCC and ccpRCC.

Vascular architectural patterns in clear cell renal cell carcinoma and clear cell papillary renal cell carcinoma.

Renal cell carcinomas (RCC) are well-vascularized tumors. Although clear cell RCC (CCRCC) show a characteristic vascular network, some cases show overlapping features with other RCC. We aimed to evaluate vascular architectural patterns, microvessel density (MVD), and endothelial cell density (ECD) in CCRCC compared to clear cell papillary RCC (ccpRCC). Thirty-four RCC (17 CCRCC and 17 ccpRCC) were included in the study. CD34 was used to evaluate vascular architectural patterns by microscopic estimation in all cases. CD34, ERG, and Bioquant Osteo 2019 Imaging Analysis Software were used to evaluate MVD and ECD in 17 CCRCC and 15 ccpRCC. Mean MVD was 526.63 in CCRCC vs. 426.18 in ccpRCC (p = 0.16); mean ECD was 937.50 in CCRCC vs. 1060.21 in ccpRCC (p = 0.25). CD34 highlighted four distinct vascular architectural patterns: pseudoacinar, Golgi-like, lacunae, and scattered. Lacunae and pseudoacinar was the most frequent combination in CCRCC; lacunae and Golgi-like was the predominant combination among ccpRCC. Pseudoacinar was most extensive in CCRCC and least in ccpRCC; Golgi-like was predominant in ccpRCC and uncommon in CCRCC. The extent of pseudoacinar and Golgi-like vascular architectural patterns was significantly different between CCRCC and ccpRCC (p < 0.05). Pathologists acquainted with these different vascular architectural patterns may utilize them as an additional tool in the distinction of CCRCC from ccpRCC.

Clear Cell Papillary Renal Cell Carcinoma Shares Distinct Molecular Characteristics and may be Significantly Associated With Higher Risk of Developing Second Primary Malignancy.

Traditionally, clear cell papillary renal cell carcinoma (ccpRCC) was considered to share similar molecular and histological characteristics with clear cell renal cell carcinoma (ccRCC) and papillary renal cell carcinoma (pRCC). Here we aimed to identify somatic and germline variants of ccpRCC. For this purpose, we conducted whole-exome sequencing to detect somatic variants in the tissues of 18 patients with pathologically confirmed ccpRCC, who underwent surgical treatment at Fudan University Shanghai Cancer Center. Targeted sequencing was conducted to detect germline variants in paired tumor or normal tissues or blood. Somatic and germline variants of ccRCC and Renal cell carcinoma included in The Cancer Genome Atlas data and other published data were analyzed as well. The molecular profiles of ccpRCC, ccRCC and pRCC were compared. Among the 387 somatic variants identified, TCEB1 (3/18) and VHL (3/18) variants occurred at the highest frequencies. Germline mutation detection showed that nine variants associated with Fanconi anemia (VAFAs) pathway (FANCA, 6/18; FANCI, 3/18) were identified in 18 ccpRCC patients. Among ccpRCC patients with VAFAs, five out of eight patients had second primary malignancy or family history of cancer. Somatic variants characteristics may distinguish ccpRCC from ccRCC or pRCC and germline VAFAs may be a molecular characterization of ccpRCC. Compared with ccRCC or pRCC, ccpRCC patients may be significantly correlated with higher risk of developing second primary malignancy.

Relationship between miR-155 expression and clear cell papillary renal cell carcinoma in the dialyzed kidney.

INTRODUCTION: Clear cell papillary renal cell carcinoma often develops in the context of the dialyzed kidney (end-stage renal disease). However, the relationship between clear cell papillary renal cell carcinoma and microRNA expression in patients with end-stage renal disease remains unclear. CASE PRESENTATION: A left renal tumor measuring 22 mm was detected and a radical nephrectomy was performed on a 50-year-old man who had received hemodialysis for the past 6 years. A pathological diagnosis of pT1aNxMx, clear cell papillary renal cell carcinoma was made. We studied the expression of miR-155 in this case and compared it to the expression in nondialysis kidney tissue. The expression level of miR-155 was upregulated in tumor tissue compared with expression levels in the renal cortex for the present case. The expression level of miR-155 in the renal cortex was lower in the present case than in nondialysis kidney tissues. CONCLUSION: We demonstrated upregulation of miR-155 in a case of clear cell papillary renal cell carcinoma arising from end-stage renal disease.

Clear cell papillary renal cell carcinoma: an update after 15 years.

Fifteen years since the first recognition of clear cell papillary renal cell carcinoma, this distinct renal tumour type is now well accepted as a distinct entity in major classification schemes. It occurs both with and without end-stage renal disease and may be multifocal or bilateral in both scenarios. Recognisable morphological features include clear cells lining branching glands and variable papillary formations with nuclear alignment. Most tumours are small (pT1a) and nucleolar grade 1-2. Immunohistochemistry consistently shows positivity for carbonic anhydrase IX and cytokeratin 7, and often high molecular weight cytokeratin or GATA3, the latter suggesting distal nephron phenotype. Labeling for AMACR and CD10 is consistently negative or minimal. Despite a resemblance to clear cell renal cell carcinoma, molecular alterations of VHL and chromosome 3p are typically lacking, with debatable rare exceptions. Potential mimics include clear cell renal cell carcinoma (with branching architecture or nuclear alignment), papillary renal cell carcinoma with clear cytoplasm, or rarely MITF family translocation renal cell carcinoma. Clinical behaviour is highly favourable with rare, debatable reports of aggressive behaviour. Combined with striking similarity to several extrarenal benign neoplasms, it would be reasonable to reclassify this entity as a benign or low malignant potential neoplasm. Using the nomenclature of the extrarenal counterparts, clear cell papillary (cyst)adenoma is proposed.

Characteristics of Clear Cell Papillary Renal Cell Carcinoma (ccpRCC).

Renal cell carcinomas (RCCs) is a group of various malignant tumours of the renal cortex displaying distinct clinical, morphologic, and genetic features. Clear cell papillary renal cell carcinoma (ccpRCC), belonging to this group, shares morphologic features with both clear cell renal cell carcinoma (ccRCC) and papillary renal cell carcinoma (pRCC) and therefore, more strict diagnostic criteria should be developed to avoid misdiagnosis. Despite overlapping features, ccpRCC has also distinct clinical behaviour, histologic characteristics (morphologic and immunohistochemical), and genomic features. The concepts concerning this tumour are constantly developing since its biological potential and molecular basis remains to be fully unravelled. First reports indicated the presence of ccpRCC in end-stage renal disease, and they underlined the enriched development in this group of patients; however, currently, it is known that such tumours can also occur spontaneously in the normal kidney. Numerous studies have demonstrated that clinical outcomes and prognosis of ccpRCC patients is highly favourable. Till now, no convincing evidence of metastatic ccpRCC or death caused by the disease has been found. Therefore, it is of high importance to correctly differentiate ccpRCC from other subtypes of RCC with a much worse prognosis and to introduce appropriate management.

Cytomorphologic analysis of clear cell papillary renal cell carcinoma: Distinguishing diagnostic features.

BACKGROUND: Clear cell papillary renal cell carcinoma (CCPRCC) shares histomorphologic and immunophenotypic features with clear cell RCC (CCRCC) and papillary RCC (PRCC). METHODS: We compared the cytomorphology, immunoprofile, and clinical management of CCPRCC (n = 18), CCRCC (n = 20), and PRCC (n = 18). RESULTS: Useful cytomorphologic features for comparing CCPRCC with CCRCC include 3-dimensional clusters (72% vs 0%), papillae (50% vs 0%) and sheets (22% vs 70%), vasculature (papillary vs traversing), naked nuclei (17% vs 100%), prominent nucleoli (0% vs 65%), and amount of cytoplasm (small vs large). Useful cytomorphologic features for comparing CCPRCC with PRCC include sheets (22% vs 61%), naked nuclei (17% vs 67%), nuclear grooves (5% vs 67%) and inclusions (17% vs 67%), and pigmented cytoplasm (17% vs 83%). At on-site evaluation, 16 of 18 (86%) CCPRCC specimens were deemed adequate, with suspicion for CCPRCC in 5 of 16 (31%) cases. Core histology of CCPRCC showed low-grade malignant cells in nests (67%), tubules (100%), and papillae (72%), frequently in myxohyaline stroma (67%). Immunostains demonstrated expression of cytokeratin 7 (CK7; 100%), carbonic anhydrase IX (CA IX; 100%, cup-like), CD10 (53%, reverse cup-like), and α-methylacyl-CoA racemase (AMACR; 35%). Among 18 CCPRCC patients, 9 (50%) underwent nephrectomy, 5 (28%) underwent cryo-ablation, and 4 (22%) were under surveillance with serial imaging. CONCLUSION: Certain morphologic features represent diagnostic criteria of CCPRCC in cytology specimens and help distinguish CCPRCC from CCRCC and PRCC. Immunostaining patterns with CK7, CA IX, CD10, and AMACR can confirm the diagnosis. Delineating CCPRCC from more biologically aggressive RCC types in cytology specimens enhances presurgical and clinical management of patients given CCPRCC's low-grade, indolent behavior.

[IPSILATERAL SYNCHRONOUS MUCINOUS TUBULAR AND SPINDLE CELL CARCINOMA AND CLEAR CELL PAPILLARY RENAL CELL CARCINOMA: A CASE REPORT AND REVIEW OF THE LITERATURE].

Renal cell carcinoma (RCC), the most common solid lesion of the kidney, accounts for approximately 2%-3% of all malignancies among adults. Clear cell carcinoma and papillary cell carcinoma are the most common types of renal tumors. Some case reports have described synchronous benign and malignant tumors in the same kidney. In particular, angiomyolipoma and RCC in patients with tuberous sclerosis (TSC) and non-TSC have been reported many times in the literature. However, unilateral concordance of malignant renal tumors is very rare; thus, only few cases have been reported in the literature.Here we report the case of a 58-year-old male who had ipsilateral synchronous mucinous tubular and spindle cell carcinoma (MTSCC) and clear cell papillary renal cell carcinoma (CCPRCC). Both cancers are rare and relatively recently defined subtypes of RCC. Additionally, both were successfully treated using partial nephrectomy. MTSCC has been a distinct entity in the World Health Organization classification of kidney tumors since 2004. The classic type of MTSCC is characterized by small elongated tubules lined with clear cuboidal or spindle cells with mucinous stroma. Neoplastic cells always exhibit low-grade histological features. However, unclassified variants of MTSCC, such as mucin-poor, papillary, high-grade, and sarcomatoid variants, have also been reported. MTSCC is considered to have a relatively good prognosis, but some patients with poor prognoses have recently been reported. CCPRCC is a recently recognized entity and represents the fourth most common variant of RCC. It has unique morphological and immunohistochemical features and shows indolent clinical behavior. Microscopically, CCPRCC may mimic other RCCs with clear cell features, such as clear cell RCC, translocation RCC, and papillary RCC, with clear cell changes. In 2006, CCPRCC was described as a subtype of renal tumors in patients with end-stage renal disease. However, currently, CCPRCC has also been shown to occur in kidneys with normal function.To the best of our knowledge, this is the first report of ipsilateral synchronous MTSCC and CCPRCC, which we present with a review of the pertinent literature.

Clear Cell Papillary Renal Cell Carcinoma: A Recent Entity With Distinct Imaging Patterns.

OBJECTIVE. Clear cell papillary renal cell carcinoma (RCC), an entity with strikingly indolent behavior, recently was added to the World Health Organization classification of renal tumors and represents the fourth most common histologic type of renal cell carcinoma. This article aims to describe the imaging features of clear cell papillary RCC along with its clinical and pathologic characteristics. MATERIALS AND METHODS. This retrospective study consisted of 27 patients with 44 clear cell papillary RCC tumors. The inclusion criteria were a pathologically proven clear cell papillary RCC and the availability of preoperative imaging including at least CT or MRI. Two experienced radiologists performed the imaging analysis independently. RESULTS. Patients (mean age, 62 years old) presented with renal failure in 26% of cases, and four had a tumor-predisposing disease. Multiple clear cell papillary RCC tumors occurred in 5 of the 27 patients. Two imaging patterns were recognizable. Solid clear cell papillary RCC (n = 23, 52%) presented as heterogeneous tumors with minor cystic changes (74%) and rarely exhibited calcifications (10%). All solid tumors showed hyperintensity on T2-weighted images compared with renal cortex and maximal enhancement on corticomedullary phase with a delayed washout. Cystic clear cell papillary RCC (n = 21, 48%) were classified as Bosniak IV (57%), III (33%), or IIF (10%), with a predominant unilocular pattern (76%). Pathologic stage according to TNM classification was mostly pT1a and low grade on nucleolar grade. All patients were alive at the date of last follow-up after treatment with no metastasis or recurrence. CONCLUSION. Clear cell papillary RCC exhibits two imaging patterns including cystic and solid in almost equal proportion. Imaging characteristics of solid clear cell papillary RCC including high signal T2 intensity and early arterial enhancement are unexpectedly distinct from papillary RCC and very similar to clear cell RCC.

Clear cell papillary renal cell carcinoma: molecular profile and virtual karyotype.

Clear cell papillary renal cell carcinoma (CCP-RCC) is a recently recognized tumor that shares morphologic features of both clear cell renal cell carcinoma and papillary renal cell carcinoma but behaves in a more indolent fashion. To date, there is little molecular information available on CCP-RCC. DNA was extracted from formalin-fixed, paraffin-embedded tissue blocks of 22 cases of CCP-RCC at the University of Alabama at Birmingham. Targeted next-generation sequencing and single-nucleotide polymorphism array were performed on all cases. Next-generation sequencing analysis found 30 somatic variants across 63.3% of cases. Seventeen variants (56.7%) were predicted to be deleterious or possibly/probably damaging. Single-nucleotide polymorphism array analysis found copy number abnormalities and/or loss of heterozygosity in 22.7% of cases. We analyzed the genetic characteristics of a group of CCP-RCCs cases and found them to be genetically different from one another. Some cases were genetically similar to clear cell renal cell carcinoma.

Distinctive clinicopathological features of Von Hippel-Lindau-associated hereditary renal cell carcinoma: A single-institution study.

Von Hippel-Lindau (VHL) disease is a genetic syndrome that involves the development of tumors in numerous organs. The kidney is one of the most frequently affected organs, and patients with VHL and renal tumors require repeated nephrectomy. The present study aimed to further determine the clinicopathological characteristics of patients with VHL-associated renal cell carcinoma (RCC), which may allow more rational clinical treatment decisions. This study included 27 patients with VHL who underwent radical or partial nephrectomy at the Peking University First Hospital between January 2010 and April 2018. The clinicopathological characteristics and prognosis of the patients were retrospectively reviewed. The expression of RCC-associated molecular markers was evaluated by immunohistochemistry. The mean size of the renal tumors was 4.3±2.0 cm (range 1.3-9.5 cm). The pathological type in 26 cases (96.3%) was clear cell RCC (CCRCC), whereas only one patient was diagnosed with CCRCC and clear cell papillary RCC. Renal cysts with a clear cell lining were observed, and RCC cell clusters were scattered in renal cyst cavities. Among the 27 patients, 21 (77.8%) were diagnosed with stage IA/T1N0M0, according to Tumor-Node-Metastasis staging, and 16 (59.3%) had grade 1 tumors. The mean postoperative follow-up duration was 39.0±24.0 months (range, 1.7-96.5 months). No metastasis or VHL-associated mortality was observed. VHL-associated RCC is a relatively low-risk disease, and a tumor size of 4 cm was determined as a threshold for nephron-sparing surgery. In addition, to prevent tumor cell dispersion, renal cysts should be carefully treated. A comprehensive understanding of the clinicopathological characteristics and underlying mechanisms of RCC associated with VHL syndrome may improve patient prognosis.

New entities, new technologies, new findings: A review of the cytologic features of recently established subtypes of renal cell carcinoma.

Several new renal tumor types with distinctive pathologic, epidemiologic, and genetic signatures have recently been adopted in the fourth edition of the World Health Organization classification. In succeeding years, the cytologic features of most of these new types have been described, adding to the trend of increasing diagnostic accuracy for most common renal cell carcinoma subtypes and the important diagnostic role of cytologic sampling in the management and personalization of therapy. The current article reviews the cytologic findings from these recently established renal cell carcinoma subtypes. Emphasis is placed on cytologic diagnostic clues, confirmatory ancillary testing, salient differential diagnoses, and challenges that can be encountered in an attempt to render accurate interpretations in small samples.

Role Of Immunohistochemistry In Subtyping Renal Cell Carcinomas With Overlapping Morphological Features.

BACKGROUND: Renal cell carcinoma (RCC), accounts for 2-3% of all new cancers diagnosed. Most renal tumours have characteristic histological features, which help in their sub classification. However, some cases do show overlapping morphology which pose a diagnostic challenge for the pathologists. Tumour ancillary studies such as immunohistochemistry (IHC) may play a significant role in segregation of these tumours. This study was undertaken to determine the role of IHC in diagnosing these tumours. METHODS: December 2015. It was carried out in histopathology laboratory of Shifa International Hospital, Islamabad. A total of fifty-five (n=55) nephrectomy specimens having RCC subtypes were included. A specific morphological diagnosis was rendered in each case on H&E.. A panel of six immunohistochemical markers CK7, CD10, CD117, CA IX, AMACR and Vimentin was then applied in each case and a final diagnosis considering both morphology and IHC was given. Statistical analysis was done using SPSS version 20.0. Mean and SD were calculated for quantitative variables where as frequencies and percentages were calculated for qualitative variables. RESULTS: Out of a total of 55 cases, 36 (65.55%) were males whereas 19 (34.5%) were females. The mean age of patients was 54.04±14.40 years. Clear cell RCC comprised 70.9% (n=39), Papillary RCC 14.5% (n=8), Chromophobe RCC 10.9% (n=6) and clear cell papillary RCC 3.6% (n=2) of cases on morphology. After application of IHC stains in all cases, 83.6% (n=46) of cases were found to have correct diagnosis on H& E. However, 16.4% (n=9) of cases could not be correctly diagnosed on morphology alone and it was in these cases that IHC played a major role in reaching a final diagnosis. CONCLUSIONS: Although most RCC subtypes display a characteristic morphology on H&E, in a significant proportion of the cases there are considerable overlapping morphological features. Our study shows that a correct diagnosis cannot be made on H & E alone in a notable number of cases. Therefore, IHC should be applied in all cases to reach a final diagnosis, which has both prognostic and therapeutic implications.

Clinical features and survival analysis of clear cell papillary renal cell carcinoma: A 10-year retrospective study from two institutions.

Clear cell papillary renal cell carcinoma (CCPRCC) is a recently recognized subtype of renal cell carcinoma entity, however, little is known about its clinical features. In the present study, 26 cases of CCPRCC were screened out from two institutions. The patient data, tissue pathology, immunohistochemical phenotype, computed tomographic images and survival analysis were studied. The mean age was 53.3 years and the average tumor size was 2.5 cm. A total of 17 patients' body mass indexes were higher than the normal level. A total of 11 patients had hypertension and 6 patients had a smoking history. Histopathologically, all cases of CCPRCC exhibited a tubular and papillary architecture, small to medium-sized cuboidal tumor cells with clear cytoplasms, and a low Fuhrman nuclear grade. All tumors were encapsulated by variably thick fibrous capsules. Immunohistochemistry showed diffuse and moderate to strong cytoplasmic staining for CK7, CA IX and vimentin, but negative for AMACR and CD10 (sometimes focally positive) in all cases. According to the results of Ki67 labeling index, the expression of Ki67 in CCPRCC was much lower than that in clear cell renal cell carcinoma (CCRCC) (2.19 vs. 7.07%, P<0.001) and that in papillary renal cell carcinoma (PRCC) (2.19 vs. 6.65%, P<0.001). Radiographically, the tumors were shown as small masses with smooth contour and mixed enhancement pattern. The multiphasic attenuation curve for CCPRCC, like that for CCRCC, increased in the corticomedullary phase markedly and decreased in the nephrographic phase and excretory phase gradually. At a median follow-up period of 50 months, no cancer-specific death or tumor recurrence was observed. Considering the favorable prognosis of CCPRCC, preoperative biopsy in order to make clear the diagnosis is particularly important. In light of the present findings, partial nephrectomy for patients with CCPRCC is recommended. If the patients cannot tolerate surgery, closed monitoring or radiofrequency ablation may be considered.