Osteogenic and sarcomatoid differentiation of a 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.

A Case of Sarcomatoid Renal Cell Carcinoma With Osseous Metaplasia and Papillary Renal Cell Carcinoma Metastasis

Sarcomatoid renal cell carcinoma is an uncommon and aggressive renal tumor with rapid disease progression. A median survival time is only 4-9 months after diagnosis. Osteogenic differentiation is a rare feature of the tumor. Here, we present a case of renal cell carcinoma with sarcomatoid feature and osteoid differentiation, and papillary renal cell carcinoma metastasis in a 58 year-old African-American male. This is the first reported renal cell carcinoma case with the combination of sarcomatoid feature, osteoid differentiation, and papillary renal cell carcinoma metastasis.

Papillary Renal Cell Carcinoma With Osteosarcomatous Heterologous Differentiation: A Case Report With Molecular Genetic Analysis and Review of the Literature

Sarcomatoid differentiation can occur in all subtypes of renal cell carcinoma (RCC). In rare cases, heterologous differentiation has been described. We present a case of heterologous osteosarcomatous differentiation in association with sarcomatoid papillary RCC including an analysis of chromosomal copy number alteration. This is the first case to identify heterologous differentiation in association with papillary RCC. The patient was a 70-year-old man who had a mass in the right kidney. Speckled calcification was seen on computed tomography scan. Histological assessment demonstrated papillary RCC merging with areas of sarcomatoid change and malignant bone formation simulating osteosarcoma. Cytogenetic evaluation demonstrated additional copies of chromosome 7 in both epithelial and osteosarcomatous components. A literature review identified 33 previous cases of heterologous differentiation in association with RCC. Of the 14 cases that reported an epithelial subtype, 13 cases were reported to be chromophobe RCC and 1 case was reported to be clear cell RCC.

The Pathology and Molecular Genetics of Sarcomatoid Renal Cell Carcinoma: A Mini-Review

Sarcomatoid renal cell carcinoma is a highly aggressive tumor. It is not a distinct histologic entity as it can be found in any subtypes of renal cell carcinoma. Recent molecular and genetic evidence suggest that sarcomatoid component is transformed from a common progenitor of the associated renal cell carcinoma, and the TP53 gene plays a pivotal role in this process. The presence of sarcomatoid carcinoma indicates poor prognosis, which also correlates with the amount of the sarcomatoid component. Therefore, the presence and quantity of sarcomatoid component should be reflected in pathology reports. However, pathology reporting seems to vary among laboratories prompting the need for a unified reporting system. We propose a pathology reporting system similar to that of transformed follicular lymphoma that is consistent with the molecular pathogenesis to ensure uniform reporting.

Sarcomatoid renal cell carcinoma with scant epithelial components in an Angora cat

CASE HISTORY

A 6-year-old, neutered, female Angora cat presented with a history of lethargy and anorexia for 2 months and a clinically palpable and gradually enlarging, solid mass in the abdominal cavity extending from the last costal arch to the pelvic cavity.

CLINICAL FINDINGS

Examination of the cat revealed jaundice, dehydration and hypothermia. Haematological manifestations included lymphopenia and substantial decrease in haematocrit value. Biochemical analysis of the blood revealed hypoglycaemia, three-fold elevated blood urea nitrogen values, increased level of serum aspartate aminotransferase and increased total bilirubin while the creatinine level was normal. Ultrasonographic examination of the abdomen showed a disrupted and large hypoechoic area around the left kidney. The cat was anaesthetised and the left kidney was removed, but the cat died following surgery.

PATHOLOGICAL FINDINGS

On post-mortem examination, the left kidney was markedly enlarged and both the cortical and medullary parenchyma were replaced by confluent, multilobulated, pale tan-white, firm nodular masses protruding above the capsular surface. Metastasis was not observed. Cytological examination revealed a population of spindle-shaped cells of variable size, with abundant coarse chromatin and occasionally prominent nucleoli. Initial sections of the kidney were indicative of undifferentiated sarcoma confirmed by immunohistochemistry revealing vimentin-positive and cytokeratin-negative results in all tumour tissues. Additional sections showed very small amounts of both cytokeratin-positive and vimentin-positive areas.

DIAGNOSIS

Sarcomatoid renal cell carcinoma (SRCC) with scant epithelial components originating from left kidney.

CLINICAL RELEVANCE

Clinical and pathological features were similar to those of human SRCC, even though there was no evidence of metastases. Immunohistochemistry for vimentin and cytokeratin may be useful for definitive diagnosis of renal cell carcinoma with sarcomatoid differentiation, although staining of sections from several different parts of the tumour may be necessary. When a primary renal tumour is presented, SRCC should be considered as this diagnosis may influence treatment protocols and the clinical outcome.

Sarcomatoid renal cell carcinoma: a comprehensive review of the biology and current treatment strategies

Recent advancements in the molecular characterization of renal cell carcinoma altered the classification system and now kidney cancer is divided into several distinct histologic subtypes. Although once a separate histologic category, sarcomatoid renal cell carcinoma is no longer considered a separate tumor type because it can occur with all histologic subtypes. Limited research on tumors with sarcomatoid change has led to minimal progress in the understanding and treatment of these tumors. Because the sarcomatoid variant of renal cell carcinoma can account for approximately one in six cases of advanced kidney cancer, we hope to familiarize clinicians with these tumors by describing the historic background, histologic features, molecular characterization, diagnosis, prognosis, treatment strategies, and active clinical trials of this aggressive type of tumor.

Histologic evaluation of metastases in renal cell carcinoma with sarcomatoid transformation and its implications for systemic therapy

BACKGROUND

Sarcomatoid features in renal cell carcinoma may represent an aggressive subclone arising from the primary tumor. The patterns of metastases for these tumors were evaluated to determine if sarcomatoid features were retained at metastasis and whether the percentage of sarcomatoid features in the primary tumor influenced spread.

METHODS

All patients with sarcomatoid features found at nephrectomy with synchronous or metachronous resection of metastases were evaluated. The histology, grade, and percentage of sarcomatoid features in the primary and metastatic site were recorded. The association between percentage of sarcomatoid features, grade, histology, and pattern of metastases was evaluated.

RESULTS

Thirty-two patients were identified with sarcomatoid features and resected metastases. Fifty-two metastatic sites were evaluated. A single histologic appearance (sarcomatoid or carcinomatoid) was present in 50 of 52 sites (96%). Thirty sites (58%) demonstrated only a sarcomatoid pattern, whereas 20 (38%) contained only a carcinoma pattern. Histology and carcinoma grade did not influence metastatic pattern; however, greater percentage of sarcomatoid features was associated with the presence of distant sarcomatoid histology. A cutoff of 30% sarcomatoid features in the primary tumor was useful in predicting systemic sarcomatoid histology.

CONCLUSIONS

Sarcomatoid elements are frequently observed in the metastases of primary tumors with sarcomatoid features, and these metastases generally contain a solitary pattern supporting the subclone hypothesis. However, both components can metastasize in the same patient. The percentage of sarcomatoid features influences the pattern of spread, and patients with >30% sarcomatoid features in the primary tumor frequently have distant sarcomatoid histology. This cutpoint may be helpful for inclusion criteria for future clinical trials.

[Sarcomatoid carcinoma of the kidney. Report of a new case and review of the bibliography]

We report a new case of sarcomatoid renal cell carcinoma, in a male of 67 years old, with locoregional recidive four months after first surgery, with two episodes of retroperitoneal hemorrhage after second surgery. The objective of this work is to contribute a new case and of doing one revision.

Carcinoma renal sarcomatóide: achados de imagem e anatomopatológicos. A propósito de um caso

O carcinoma renal sarcomatóide é uma neoplasia agressiva cujas características clínicas e radiológicas são similares às do carcinoma de células renais convencionais (células claras). O tumor é composto por camadas de células fusiformes malignas com aspectos imuno-histoquímicos e ultra-estruturais de células epiteliais e estromais, também podendo conter áreas mixóides de células gigantes osteoclasto-símile, células pleomórficas rabdomioblasto-símile, bem como outros componentes sarcomatóides raros. Os autores relatam um caso de carcinoma renal sarcomatóide em paciente do sexo masculino, com 54 anos de idade, apresentando a clássica tríade clínica do carcinoma de células renais. Ressaltam, também, as características macroscópicas e microscópicas típicas da lesão, e discutem os achados dos métodos de imagem e seu diagnóstico diferencial com sarcomas renais verdadeiros.

Chromophobe renal cell carcinoma with osteosarcoma-like differentiation

Sarcomatoid differentiation in renal cell carcinoma is thought to be the result of the dedifferentiation of the parent tumor, and it can be found in the chromophobe renal cell carcinoma just as other subtypes. We report a case of chromophobe renal cell carcinoma, which showed osteosarcoma-like differentiation. This is the first known case ever to be clearly identified as such. The patient was a 74-year-old man, and the CT scan revealed a huge retroperitoneal mass, which protruded from the lower half of the kidney and directly invaded the colon. Intraabdominal dissemination and metastases to the liver and lungs were also found. The resected tumor histologically showed sarcoma-like spindle cell proliferation and partly produced massive osteoid, which simulated the osteosarcoma. In addition, a typical histology of chromophobe renal cell carcinoma was found in part of the tumor. Immunohistochemically, spindle cells were reactive for epithelial membrane antigen, cytokeratin, and vimentin. The cell nests that were labeled by epithelial membrane antigen and cytokeratin were also found in the osteosarcoma-like area. We think that these phenomena were the result of "dedifferentiation" and metaplasia of the chromophobe renal cell carcinoma.

Sarcomatoid renal cell carcinoma with scant carcinomatous components

A 30-year-old male underwent radical nephrectomy for a right renal tumor 15 cm in diameter. On microscopic examination of initial 17 sections, the tumor consisted of pleomorphic giant cells and spindle neoplastic cells. There was no carcinomatous component. Immunohistochemically, the neoplastic cells were negative for keratin and epithelial membrane antigen but positive for vimentin. The giant cells were also scatteringly, weakly positive for myoglobin. At that time a diagnosis of rhabdomyosarcoma of the kidney was made. However, further microscopic examination of another eight sections revealed small areas of clear cell-type renal cell carcinoma (RCC) which transited to sarcomatous components and led to a diagnosis of sarcomatoid RCC. The patient underwent three cycles of adjuvant chemotherapy. He has been free of the disease for 14 months after nephrectomy.

Sarcomatoid renal carcinoma: the final common dedifferentiation pathway of renal epithelial malignancies

Sarcomatoid renal carcinoma (SRC) is an aggressive neoplasm with an age and gender distribution similar to that of conventional (clear cell) renal cell carcinoma (RCC). Genetic and morphologic evidence indicates that the tumor results from de-differentiation of renal epithelial malignancy and associations with RCC, papillary renal carcinoma, chromophobe renal carcinoma and collecting duct carcinoma have been reported. The tumor is composed of sheets of malignant spindle cells that have immunohistochemical and ultrastructural features of both stromal and epithelial cells, and may contain myxoid areas containing osteoclast-like giant cells or pleomorphic sarcomatoid spindle cells resembling rhabdomyoblasts. Rare cases of osteogenic SRC have been described. The tumor shows marked proliferative activity in growth kinetic studies and is usually associated with a poor patient survival that is best predicted by staging.

Epithelial-mesenchymal transdifferentiation and extracellular matrix gene expression in pleomorphic adenomas of the parotid salivary gland

Mesenchymal and epithelial cell differentiation are assumed to be dichotomic primary events in embryonic development. In this study, pleomorphic adenomas of the parotid gland were analysed as a model which shows morphological features of both epithelial and mesenchymal tissue types. Using matrix gene expression profiles as a supplementary criterion for the identification of cellular phenotypes, areas with unequivocal epithelial and mesenchymal differentiation could be demonstrated. Many areas displayed a transitional phenotype with cells showing both epithelial and mesenchymal features. The data provide evidence that epithelial-mesenchymal transitions represent the basic principle of the tisuse heterogeneity in pleomorphic adenomas. Thus, pleomorphic adenomas demonstrate the potential of adult (neoplastic) epithelial cells to transdifferentiate into mesenchymal cells in vivo.

Sarcomatoid renal cell carcinoma: the chromophobe connection

Eleven cases of sarcomatoid renal cell carcinoma were studied to determine the relative frequency of various subtypes of renal cell carcinoma that may be associated with sarcomatoid transformation. The epithelial components in these tumors were subcategorized according to established histologic criteria into chromophobe carcinoma (n = 6 cases), clear cell carcinoma (n = 3), papillary carcinoma (n = 1), and indeterminate (n = 1). In nine cases, material was available for immunohistochemical and DNA ploidy studies. The sarcomatoid component in all cases showed positivity for epithelial membrane antigen cytokeratin, indicating an epithelial derivation of these cells. Staining for mesenchymal markers was mostly negative, except for vimentin, which reacted strongly in all cases. DNA ploidy studies using flow cytometry and cell image analysis provided very similar results. Five of five chromophobe sarcomatoid carcinomas showed hypodiploid cell lines in the epithelial areas, whereas the sarcomatoid components mostly showed aneuploid peaks. In the remaining cases, DNA ploidy pattern was more variable. These findings indicate that chromophobe carcinoma may be the most frequent epithelial component associated with sarcomatoid renal cell carcinoma.

Sarcomatoid carcinoma: an ultrastructural study with light microscopic and immunohistochemical correlation of 10 cases from various anatomic sites

The histogenesis of sarcomatoid carcinoma has been an intriguing topic for pathologists for many years, and considerable evidence has accumulated in the fields of tissue culture, electron microscopy, and immunohistochemistry to support the concept that the sarcomatous cells derive by way of "divergent differentiation" (metaplasia) from the carcinomatous elements. We have studied a group of 10 cases of these tumors from various organs, using detailed ultrastructural analysis as well as light microscopic and immunohistochemical correlation. We found that there is an ultrastructural spectrum of differentiation from epithelial to mesenchymal type features and that the malignant spindle cells may be purely epithelial (3 cases), purely mesenchymal (3 cases), or a mixture of both (4 cases). Furthermore, individual cells may show biphasia, having desmosomes and tonofibrils as well as well developed rough endoplasmic reticulum and filaments with dense bodies. Electron microscopic and immunohistochemical results do not always correlate, illustrating the prudence of using several keratin antibodies, including wide-spectrum ones, and of performing electron microscopic examination on these tumors.

Malignant mesenchymoma of the prostate: immunohistochemical and ultrastructural observations

A case of malignant mesenchymoma of the prostate is reported. Immunohistochemical and ultrastructural examination revealed malignant chondro-osteoblastic and rhabdomyoblastic features. A separate incidental prostatic adenocarcinoma was also seen. These lesions should be differentiated from carcinosarcoma in which adenocarcinoma is intermingled with malignant mesenchymal components.

Renal cell carcinoma with osteosarcomatous differentiation simulating staghorn calculus: a case report and literature review

We report a case of renal cell carcinoma that showed extensive osteosarcomatous differentiation and simulated a staghorn calculus clinically and radiologically. The literature on osteosarcomatous differentiation in renal cell carcinoma is reviewed.

Primary renal sarcoma in adults. A natural history and management study by the American Cancer Society, Illinois Division

BACKGROUND

Primary renal sarcomas in adults are rare and unusual neoplasms. This study was performed to better define the natural history and current management of these sarcomas in a typical medical setting in the United States.

METHODS

The hospital records of 4018 adult patients with renal neoplasms treated in the state of Illinois from 1975 to 1985 were examined by American Cancer Society professional volunteers.

RESULTS

A primary renal sarcoma occurred in 34 patients (0.8% incidence). Eleven adult patients had Wilms tumor, 21 had primary renal sarcoma (47% leiomyosarcoma), and 2 were not found to have sarcoma on review. The median age of the patients with Wilms tumor was 30 years, whereas that of the patients with non-Wilms sarcoma was 65 years. Four of the patients with Wilms tumor (36%) are long-term survivors and all received adjuvant chemotherapy after radical nephrectomy. Six of the patients with non-Wilms sarcoma (29%) are long-term survivors after radical nephrectomy alone.

CONCLUSIONS

Primary renal sarcomas, when treated with radical nephrectomy and, in the case of Wilms tumor, adjuvant chemotherapy, appear to be curable in 29-36% of cases. Histologic review of patients younger than 40 years of age with renal neoplasia is recommended.

Sarcomatoid renal cell carcinoma. An immunohistochemical and ultrastructural study

A case of sarcomatoid renal cell carcinoma is reported with light, immunohistochemical and electron microscopic findings. The tumour consisted of typical clear cells of renal cell carcinoma and spindle cells compatible with malignant fibrous histiocytoma (MFH). Although an epithelial membrane antigen was demonstrated in the clear cells, this was not detected in the MFH-like spindle cells. In contrast, the spindle cells expressed vimentin that was not identified in the clear cells. Electron microscopy reveal epithelial features in the spindle cells. Comparisons were made with previous sarcomatoid renal cell carcinoma in the literature. Thus, ultrastructural study was vital in diagnosis of sarcomatoid renal cell carcinoma.

Sarcomatoid renal cell carcinoma metastatic to the heart: report of a case

An unusual case of metastatic sarcomatoid renal cell carcinoma is presented. Fifteen months after nephrectomy for a typical clear cell carcinoma, a 63-year-old man presented with bilateral pleural effusions, cardiomegaly, and tamponade. A pericardial biopsy showed an anaplastic spindle cell tumor that was strongly keratin positive and showed desmosomes ultrastructurally. The patient died shortly thereafter, and the autopsy revealed massive tumor infiltration of the heart, pulmonary and adrenal metastases, and tumor nodules at the incision site of his nephrectomy. The differential diagnosis of sarcomatoid renal cell carcinoma is discussed.

Hepatoblastoma: an immunohistochemical and ultrastructural study

The ultrastructural and immunohistochemical features of 19 hepatoblastomas were examined to evaluate the phenotypic expressivity of this solid embryonic neoplasm of childhood. Electron microscopy confirmed the embryonal and fetal characteristics of the neoplastic hepatocytes, but in addition, cells with features intermediate between these two cell types were identified. Dense bundles of collagen corresponding to the osteoid-like material by light microscopy surrounded nests of cells; the cells within this matrix stained for epithelial membrane antigen and vimentin and focally for cytokeratin, and they showed ultrastructural features of epithelial cells. The two cases of small cell hepatoblastoma reacted positively for vimentin and cytokeratin; the remaining 17 cases were immunoreactive for cytokeratin and alpha-fetoprotein, and some also for alpha 1-antitrypsin, ferritin, and vimentin. A histogenetic scheme based on our findings is proposed to explain the divergent morphologic features of this neoplasm.

Sarcomatoid renal tumors. Clinicopathologic correlation of three cases

The clinical, light and ultrastructural features of three renal neoplasms demonstrating a sarcomatous appearance on light microscopic examination are reported. At the time of radical nephrectomy, all three tumors displayed aggressive features with capsular invasion and either metastases or invasion of adjacent organs. Ultrastructural examination revealed epithelial features in a pure spindle cell tumor and in a malignant fibrous histiocytoma-like tumor (sarcomatoid renal carcinoma) and smooth muscle differentiation (leiomyosarcoma) in a lesion showing features of malignant fibrous histiocytoma. All three patients died from 1 to 9 months after nephrectomy. Renal tumors with a sarcomatous histologic appearance are aggressive neoplasms that cannot be classified accurately solely by employing light microscopic criteria.

Sarcomatoid renal cell carcinoma: clinicopathologic. A study of 42 cases

Forty-two cases of sarcomatoid renal cell carcinoma were reviewed clinicopathologically. Twenty-four patients were men, and 18 women; average age was 56.2 years (range, 30-81 years). Eight, 9, 13, and 12 cases were Stages I, II, III, and IV, respectively. Three morphologic patterns of sarcomatoid components were identified: malignant fibrous histiocytomatous (26 cases), fibrosarcomatous (6 cases), and unclassified sarcomatoid (10 cases). Mitotic count, degree of pleomorphism, cellularity, and amount of tumor matrix in the sarcomatoid areas, and similar morphologic parameters in the carcinomatous component all failed to correlate with prognosis, as did tumor size and renal vein involvement by tumor. Clinicopathologic stage was a most significant prognostic factor, with a survival of 49.7 months for Stage I and 6.8 months for combined Stages II, III, and IV. Tumor necrosis in the sarcomatoid area and proportion of sarcomatoid components were also poor prognostic factors. When these factors were compared to the stage, necrosis was an independent variable, however, proportion of sarcomatoid components was a poor prognostic indicator only for Stages I and II.