Rhabdoid differentiation of chromophobe renal cell carcinoma

Sarcomatoid and Rhabdoid Renal Cell Carcinoma: Clinical, Pathologic, and Molecular Genetic Features

Renal cell carcinoma (RCC) with sarcomatoid and rhabdoid morphologies has an aggressive biological behavior and a typically poor prognosis. The current 2022 WHO classification of renal tumors does not include them as distinct histologic entities but rather as transformational changes that may arise in a background of various distinct histologic types of RCC. The sarcomatoid component shows malignant spindle cells that may grow as intersecting fascicles, which is reminiscent of pleomorphic undifferentiated sarcoma. The rhabdoid cells are epithelioid cells with eccentrically located vesicular nuclei with prominent nucleoli and large intracytoplasmic eosinophilic inclusions. Studies have shown that RCCs with sarcomatoid and rhabdoid differentiation have distinctive molecular features. Sarcomatoid RCC harbors shared genomic alterations in carcinomatous and rhabdoid components, but also enrichment of specific genomic alterations in the sarcomatoid element, suggesting molecular pathways for development of sarcomatoid growth from a common clonal ancestor. Rhabdoid differentiation also arises through clonal evolution although less is known of specific genomic alterations in rhabdoid cells. Historically, treatment has lacked efficacy, although recently immunotherapy with PD-1/PD-L1/CTLA-4 inhibitors has produced significant clinical responses. Reporting of sarcomatoid and rhabdoid features in renal cell carcinoma is required by the College of American Pathologists and the International Collaboration on Cancer Reporting. This manuscript reviews the clinical, pathologic, and molecular features of sarcomatoid RCC and rhabdoid RCC with emphasis on the morphologic features of these tumors, significance of diagnostic recognition, the molecular mechanisms of tumorigenesis and differentiation along sarcomatoid and rhabdoid lines, and advances in treatment, particularly immunotherapy.

The significance of sarcomatoid and rhabdoid dedifferentiation in renal cell carcinoma

Dedifferentiation in renal cell carcinoma (RCC), either sarcomatoid or rhabdoid, is an infrequent event that may occur heterogeneously in the setting of any RCC histology and is associated with poor outcomes. Sarcomatoid dedifferentiation is associated with inferior survival with angiogenesis targeted therapy and infrequent responses to cytotoxic chemotherapy. However, immune checkpoint therapy has significantly improved outcomes for patients with sarcomatoid dedifferentiation. Biologically, sarcomatoid dedifferentiation has increased programmed death-ligand 1 (PD-L1) expression and an inflamed tumor microenvironment, in addition to other distinct molecular alterations. Less is known about rhabdoid dedifferentiation from either a clinical, biological, or therapeutic perspective. In this focused review, we will discuss the prognostic implications, outcomes with systemic therapy, and underlying biology in RCC with either sarcomatoid or rhabdoid dedifferentiation present.

Updates in Histologic Grading of Urologic Neoplasms

CONTEXT.—

Tumor histology offers a composite view of the genetic, epigenetic, proteomic, and microenvironmental determinants of tumor biology. As a marker of tumor histology, histologic grading has persisted as a highly relevant factor in risk stratification and management of urologic neoplasms (ie, renal cell carcinoma, prostatic adenocarcinoma, and urothelial carcinoma). Ongoing research and consensus meetings have attempted to improve the accuracy, consistency, and biologic relevance of histologic grading, as well as provide guidance for many challenging scenarios.

OBJECTIVE.—

To review the most recent updates to the grading system of urologic neoplasms, including those in the 2016 4th edition of the World Health Organization (WHO) Bluebook, with emphasis on issues encountered in routine practice.

DATA SOURCES.—

Peer-reviewed publications and the 4th edition of the WHO Bluebook on the pathology and genetics of the urinary system and male genital organs.

CONCLUSIONS.—

This article summarizes the recently updated grading schemes for renal cell carcinoma, prostate adenocarcinomas, and bladder neoplasms of the genitourinary tract.

Chromophobe renal cell carcinoma: New genetic and metabolic insights

Chromophobe renal cell carcinoma (chRCC) represents 5% of all RCC. ChRCC appears to arise from the distal nephron, in contrast to clear cell RCC that arises from the proximal nephron. ChRCC is distinctive because the tumor cells contain abundant abnormal mitochondria, and frequently have loss of one copy of multiple chromosomes, with a low rate of somatic mutations. Here, we focus on recent discoveries related to genetic and metabolic factors that may promote the progression of chRCC and summarize how these findings may relate to the prognosis and treatment of chRCC.

A Composite Renal Tumor with Dual Differentiation, Chromophobe and Collecting Duct Carcinoma

Chromophobe carcinoma constitutes a small subset of all renal carcinomas. Within this category, rare tumors with divergent differentiation have been recognized. Herein, we report a rare case of composite chromophobe and collecting duct carcinoma and describe its pathologic and clinical features.

Malignant rhabdoid tumor in the renal allograft of an adult transplant recipient: a unique case of a rare tumor

Background

Renal transplant recipients have increased risk for developing malignant diseases because of immunosuppression or donor-to-recipient transmission. Malignant rhabdoid tumor (MRT) is a rare, highly aggressive and lethal tumor primarily affecting the kidney of infants and young children. MRT has not been reported in the renal allograft of an adult recipient after kidney transplantation.

Case presentation

In this report, a 47-year-old woman who received a kidney transplantation from an infant donor and developed a mass in the transplanted kidney is presented. Pathological examinations revealed a malignant tumor with rhabdoid cells morphologically and the loss of INI1 expression immunohistochemically. The diagnosis of malignant rhabdoid tumor in the transplanted kidney was made. We confirmed that donor-to-recipient malignancy transmission was the cause of MRT in the transplanted kidney by fluorescence in situ hybridization (FISH) and short tandem repeat (STR) analysis.

Conclusion

To our knowledge, this is the first case of MRT in an adult renal allograft recipient. This report highlights the importance of the criteria for selection of donors to screen possible malignant tumors transmission.

Rhabdoid differentiation is associated with aggressive behavior in renal cell carcinoma: a clinicopathologic analysis of 76 cases with clinical follow-up

Rhabdoid differentiation has been associated with aggressive behavior in carcinomas from different organ systems. A recent consensus statement of the International Society of Urological Pathology (ISUP), in addition to proposing a nucleolar grading system (ISUP grade) for renal cell carcinoma (RCC) to replace the Fuhrman system, recommended reporting the presence of rhabdoid differentiation in RCC and considering tumors with rhabdoid differentiation to be ISUP grade 4. Although it has been shown that rhabdoid differentiation is associated with increased grade and stage of RCC, it has not been fully demonstrated whether it has an adverse effect independent of this association with increased grade and stage. We provide the largest clinicopathologic analysis of RCC with rhabdoid differentiation to date (76 cases), including characterization of metastatic disease. In addition, by constructing a multivariable model including tumor grade, stage, necrosis, and distant metastasis to compare a series of 49 clear cell RCC with rhabdoid differentiation with a cohort of 41 clear cell RCCs without rhabdoid differentiation, we demonstrate that the presence of rhabdoid differentiation in clear cell RCC confers an increased risk of death (hazard ratio=5.25; 95% confidence interval, 2.1-14.3) independent of these other adverse prognostic factors. These findings underscore the significance of rhabdoid differentiation in RCC as an adverse prognostic factor and support the recent reporting and grading recommendations of the ISUP.

Two cases of eosinophilic variant chromophobe renal cell carcinoma, with a rare association of right atrial myxoma in one of them

Chromophobe renal cell carcinoma is a relatively uncommon variant of renal cell carcinoma. Eosinophilic variant of chromophobe renal cell carcinoma (EVCRCC) is still less frequent and is composed predominantly of small to medium-sized cells with abundant granular eosinophilic cytoplasm. We report two cases of EVCRCC, with one having a rare association of right atrial myxoma. We present these cases, due to the rarity of EVCRCC and an unusual association of right atrial myxoma in one of them. Both patients recovered well after surgery, with no recurrence or metastasis after 2 years of follow-up.

Treatment of adult rhabdoid renal cell carcinoma with sorafenib

Renal cell carcinoma (RCC) with rhabdoid features is an uncommon and highly aggressive malignancy. We report a case of adult clear-cell RCC with extensive rhabdoid features treated with the tyrosine kinase inhibitor sorafenib. A review of the literature summarizes important aspects of this malignancy. We discuss clinical and histological findings as well as the patient's response to sorafenib therapy.

Adult renal cell carcinoma with rhabdoid morphology represents a neoplastic dedifferentiation analogous to sarcomatoid carcinoma

Renal cell carcinoma (RCC) with rhabdoid morphology (RCC-RM) is a recently described variant of RCC, which has an aggressive biologic behavior and poor prognosis, akin to sarcomatoid RCC. The current World Health Organization classification of RCC does not include the rhabdoid phenotype as a distinct histologic entity. The aim of this study is to investigate whether RCC-RM represents a dedifferentiation of a classifiable-type World Health Organization RCC or a carcinosarcoma with muscle differentiation. We reviewed 168 cases of RCC obtained between 2003 and 2008. From these cases, 10 (6%) were found to have areas of classic rhabdoid morphology. Immunohistochemistry for cytokeratin, epithelial membrane antigen, desmin, CD10, and CD117 was performed in each case using the labeled streptavidin-biotin method. Rhabdoid differentiation was identified in association with conventional-type RCC (9) and with unclassifiable-type RCC with spindle cell morphology (1). In all cases, both the rhabdoid and nonrhabdoid tumoral areas were positive for cytokeratin and epithelial membrane antigen and negative for desmin. Cytokeratin positivity in the rhabdoid areas was focal. In cases associated with conventional-type RCC, CD10 was positive in both the rhabdoid and nonrhabdoid foci. CD117 was negative in these tumors. The unclassifiable-type RCC with spindle cell morphology was negative for both CD10 and CD117. The similar immunophenotype between the rhabdoid and nonrhabdoid tumoral foci supports the origin of the rhabdoid cells from the classifiable-type RCC. Areas of rhabdoid morphology do not represent muscle metaplastic differentiation. Renal cell carcinoma with rhabdoid morphology may represent a dedifferentiation of a classifiable-type RCC, similar to that of sarcomatoid differentiation. The recognition of RCC-RM is important as it allows for the inclusion of these high-grade malignancies into a category associated with poor prognosis despite lacking the spindle cell component classically identified as sarcomatoid change.

Can renal oncocytoma be distinguished from chromophobe renal cell carcinoma by the presence of fibrous capsule?

The most important differential diagnosis of chromophobe renal cell carcinoma (CRCC) is renal oncocytoma. Due to overlapping morphological characteristics of renal oncocytoma and CRCC, particularly its eosinophilic variant, making a correct diagnosis can be challenging. To date, no data are available on the presence of the tumor fibrous capsule as a diagnostic feature in differentiating these tumors. The main purpose of this study was to establish the presence and compare the thickness of the tumor fibrous capsule between two tumor groups. A total of 37 tumors--18 cases of CRCC (three eosinophilic and 15 classic) and 19 cases of renal oncocytoma--were analyzed. Four slides of each tumor stained with hematoxylin and eosin were first scanned at low-power magnification (x40) to assess the presence of the capsule. If present, the capsule was measured in three different thickest areas at higher magnification (x200). The mean value of capsule thickness was calculated and taken into consideration. The capsule was present in 12 (66.7%) cases of CRCCs and in only two (10.5%) cases of renal oncocytomas. Statistical analysis showed significant difference between the presence of fibrous capsule in these two observed tumor groups (P = 0.001). Average thickness of capsule in CRCCs was 337.7 microm, and 115.4 microm in renal oncocytomas, but the median was not statistically significant (P = 0.198). Studies with a larger number of cases are needed to conclude if this characteristic could be a low-cost, reliable microscopic feature in differentiating between CRCC and renal oncocytoma.

[Chromophobe renal cell carcinoma, an exceptional entity in childhood: a case report]

Chromophobe renal cell carcinoma (CRCC) is a rare variant of renal carcinomas arising from the intercalated cells of the distal renal tubule and representing 5% among all renal tumors. Its biological behaviour is variable, less aggresive than clear cell renal carcinoma. Histochemical, ultrastructural and molecular genetic characteristics are different from other renal carcinomas. Age at presentation is about the 6th decade of life. We report an exceptional 10 year-old boy case with a CRCC. Diagnostic and therapeutic aspects for the management of this tumor are reviewed.

Renal cell carcinoma with rhabdoid features: an aggressive neoplasm with overexpression of p53

CONTEXT

Adult renal cell carcinoma (RCC) with rhabdoid features is a recently recognized morphologic variant of kidney carcinoma. To date, only very few studies have been published on this subject and p53 was not previously studied.

OBJECTIVE

To evaluate clinical attributes, morphology, and immunohistochemistry in RCC with rhabdoid component.

DESIGN

Reviewing a consecutive series of 310 RCCs, we identified 14 cases of RCC with rhabdoid features. All cases were reviewed and subjected to detailed clinical and pathologic studies with immunohistochemical evaluation of p53.

RESULTS

All tumors were clear RCCs with rhabdoid component representing from 5% to 50% of the tumor volume. Rhabdoid cells were large with a central eosinophilic intracytoplasmic inclusion and an eccentric atypical nucleus. Tumor necrosis was common (13/14) and sometimes extensive. Nine of 14 tumors were staged pT3, 4 of 14 were pT2, and only 1 tumor was pT1. On immunohistochemistry, rhabdoid cells were positive for vimentin (14/ 14), epithelial membrane antigen (11/14), and cytokeratin (9/14). Desmin and smooth muscle actin were always negative. p53 was positive in 10 of 14 tumors in the rhabdoid areas (5%-50% of tumor cells stained) but only in 5 of 14 cases in usual clear renal cell areas. In the follow-up, 10 of 14 patients developed metastases and 6 of 14 died of the disease. The median of survival was 8 months.

CONCLUSIONS

We showed that RCC with rhabdoid features is a very aggressive neoplasm with a poor prognosis. We observed an overexpression of p53 in the rhabdoid component that may be implicated in the tumor dedifferentiation.

Aplicación clínica de las actuales clasificaciones del cáncer renal

The purpose of classifying neoplasias is to recognize groups with similar progress and prognosis and, if possible, receiving the same treatment. This is why those classifications are systematically being submitted to review and improvement through the new technologies. Differentiation of various entities in renal cancer has been comparatively fast, as the new genetic and molecular discoveries have confirmed the morphologic criteria of the different cell types, thus making it possible to open new therapeutic pathways. Using the current WHO classification we recognize subtypes with excellent prognosis (Multilocular cystic renal carcinoma, Type I renal papillary carcinoma, Tubular and fusocellular mucinous carcinoma), other very aggressive ones (Bellini's collecting duct carcinoma, Medullary carcinoma), and also that the sarcomatoid transformation, even in small areas, impacts the prognosis negatively. Childhood-characteristic renal carcinomas associated with chromosome translocations have been recognized (genetic fusion TFE3 or TFEB), as well as the family forms of renal carcinoma. Regarding the UICC (International Union Against Cancer) classification, there are a series of aspects under argument (size, venous invasion, microvascular invasion, invasion of the adipous tissue of the renal sinus) that shall be discussed too, since it is possible that some modifications of the TNM might occur in the near future.

Oncocytic renal neoplasms: diagnostic considerations

Advances in our understanding of renal neoplasia have resulted in recognition of numerous tumors that are composed predominantly of cells with abundant eosinophilic cytoplasm. This article discusses the features of renal oncocytoma (including oncocytosis), chromophobe renal cell carcinoma (RCC), and clear cell RCC; explores the relationship between renal oncocytoma and chromophobe RCC; briefly discusses other tumors with abundant eosinophilic cytoplasm; and emphasizes the differential diagnosis of such tumors.

Clear cell renal cell carcinoma

Clear cell RCC is the most common type of RCC that occurs in adults. It has the worst prognosis among the common epithelial tumors of the kidney. Histologically, a wide range of morphologic patterns can be encountered. Those cases with a multi-locular cystic architecture are considered to be a distinct subtype because of the clinicopathologic features.