Dedifferentiated chromophobe renal cell carcinoma with massive osteosarcoma-like divergent differentiation: a singular entity in the spectrum of retroperitoneal calcifying tumors

[Undifferentiated and dedifferentiated renal cell carcinomas : Morphomolecular aspects and differential diagnosis in light of recent developments]

Histological subtyping of diverse renal cell carcinomas (RCCs) has seen significant changes during the last two decades. This resulted in the introduction of several new phenotypically and genetically defined entities, many which are also listed in the current WHO classification. Some of these well-defined entities may, under certain circumstances, undergo a process of dedifferentiation resulting in loss of their phenotypic and immunohistochemical features, hence adopting a non-descript anaplastic morphology. Accordingly, the original entity-defining tumor clone might be either totally overgrown and lost or just be missed by sampling the tumor. This final common pathway of dedifferentiation results in several oncological disadvantages and prevents a histology-tailored approach to systemic therapy. In addition, the possibility of inherited cancer as in the case of SDH- and FH-deficient RCC would be easily overlooked if the exact subtyping is not possible. This overview article illuminates the main RCC subtypes that may undergo dedifferentiation and their differential diagnostic approach.

Chromophobe renal cell carcinoma with sarcomatoid and heterologous osteosarcoma-like differentiation: a case report and literature review

Chromophobe renal cell carcinoma (CRCC) is a subtype of renal cell carcinoma (RCC) with a favorable prognosis. Sarcomatoid differentiation in RCC is assumed to be the outcome of the parent tumor's dedifferentiation and associated with poorer prognosis. Sarcomatoid differentiation can be detected in CRCC as well as other subtypes, but the occurrence of divergent osteosarcoma-like components in sarcomatoid CRCC is extremely unusual. Only six cases have been previously reported in the literature, we reviewed them and presented the seventh case in a 71-year-old male who had a left kidney heterogeneous mass. The resected tumor showed a sarcoma-like spindle cell area with an adjacent osteosarcoma area producing lacy bone material and bony trabeculae in a hard area mixed with a typical CRCC. In conclusion, sarcomatoid CRCC with osteosarcomatous differentiation is a very rare tumor and should be kept in mind especially when dealing with small or frozen sections biopsies.

Clinicopathologic and Immunohistochemical Characterization of Sarcomatoid Chromophobe Renal Cell Carcinoma: An Analysis of 22 Cases

Sarcomatoid differentiation in chromophobe renal cell carcinoma (ChRCC) is a rare finding and a significant predictor of worse outcomes. When the sarcomatoid component overgrows the conventional component or is the only component on a biopsy, the differential diagnoses encompass a variety of entities. Therefore, we reviewed 22 sarcomatoid ChRCCs and characterized the immunophenotype. Given that renal carcinomas with sarcomatoid features may benefit from immune checkpoint inhibitor-based therapy we also assessed the programmed death-ligand 1 (PD-L1) (28-8) expression. DOG1, CD117, cytokeratin 7, and PAX8 were negative in 100%, 88%, 63%, and 44% of the sarcomatoid components, respectively. GATA3 was expressed in 31% of the conventional components and in 50% of the sarcomatoid components. One conventional and 3 sarcomatoid components expressed PD-L1. Sarcomatoid ChRCCs have a high propensity for metastases and cancer progression. Distant metastatic disease was seen in 73% of the cases and median survival in this cohort was <1 year. The sarcomatoid portion had increased expression of PD-L1 and frequent loss of expression of multiple immunohistochemical markers associated with ChRCC. Half of the sarcomatoid ChRCC exhibited GATA3 expression, 3 of which did not express PAX8.

Undifferentiated and dedifferentiated urological carcinomas: lessons learned from the recent developments

Loss of the morphological and immunophenotypic characteristics of a neoplasm is a well-known phenomenon in surgical pathology and occurs across different tumor types in almost all organs. This process may be either partial, characterized by transition from well differentiated to undifferentiated tumor component (=dedifferentiated carcinomas) or complete (=undifferentiated carcinomas). Diagnosis of undifferentiated carcinoma is significantly influenced by the extent of sampling. Although the concept of undifferentiated and dedifferentiated carcinoma has been well established for other organs (e.g. endometrium), it still has not been fully defined for urological carcinomas. Accordingly, undifferentiated/ dedifferentiated genitourinary carcinomas are typically lumped into the spectrum of poorly differentiated, sarcomatoid, or unclassified (NOS) carcinomas. In the kidney, dedifferentiation occurs across all subtypes of renal cell carcinoma (RCC), but certain genetically defined RCC types (SDH-, FH- and PBRM1- deficient RCC) seem to have inherent tendency to dedifferentiate. Histologically, the undifferentiated component displays variable combination of four patterns: spindle cells, pleomorphic giant cells, rhabdoid cells, and undifferentiated monomorphic cells with/without prominent osteoclastic giant cells. Any of these may occasionally be associated with heterologous mesenchymal component/s. Their immunophenotype is often simple with expression of vimentin and variably pankeratin or EMA. Precise subtyping of undifferentiated (urothelial versus RCC and the exact underlying RCC subtype) is best done by thorough sampling supplemented as necessary by immunohistochemistry (e.g. FH, SDHB, ALK) and/ or molecular studies. This review discusses the morphological and molecular genetic spectrum and the recent develoments on the topic of dedifferentiated and undifferentiated genitourinary carcinomas.

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.

Chromophobe renal cell carcinoma with sarcomatoid differentiation containing various heterologous components

Renal cell carcinoma (RCC) occasionally has sarcomatoid differentiation and rarely contains heterologous components. We report a case of chromophobe RCC with sarcomatoid differentiation that had various heterologous components including a unique lipomatous area. The patient was an 83-year-old woman with a palpable mass in the left lower abdomen. Grossly, the tumor was 14 cm in diameter and had yellowish-to-whitish color with focal necrosis and hemorrhage. Histologically, the tumor was composed of an eosinophilic subtype of chromophobe RCC with sarcomatoid differentiation including mainly chondrosarcoma, some osteosarcoma and a lipomatous area. The heterologous components of sarcomatoid RCC are usually osteosarcoma or chondrosarcoma, and sarcomatoid RCC with multiple heterologous components is extremely rare.

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.

Sarcomatoid urothelial carcinoma with chondrosarcomatous differentiation of the ureter: A case report and review of the literature

Sarcomatoid urothelial carcinoma of the urinary tract is associated with poor prognosis. The majority of sarcomatoid urothelial carcinomas are found in the urinary bladder, while a small minority have been shown to arise from the ureter. In the present case, a 72-year-old male patient was diagnosed with sarcomatoid urothelial carcinoma with chondrosarcomatous differentiation of the left ureter, and subsequently underwent nephroureterectomy and retroperitoneal lymph node dissection. Two lymph nodes from the renal hilum and one paraaortic lymph node were also found to have metastatic involvement; however, the patient refused to receive chemotherapy or radiotherapy and succumbed to bone and omentum metastasis at 6 months after the initial diagnosis. Sarcomatoid urothelial carcinoma of the ureter is uncommon. Even rarer is the presence of malignant heterologous elements, such as chondrosarcoma. The present study reports a rare case of sarcomatoid urothelial carcinoma with chondrosarcomatous differentiation of the ureter, as well as a review of the literature, in order to demonstrate the aggressive nature of this particular malignancy.

Chromophobe renal cell carcinoma with concomitant sarcomatoid transformation and osseous metaplasia: a case report

Background

Chromophobe renal cell carcinoma is the third most common form of adult renal epithelial neoplasm. A sarcomatoid component occurs in approximately 8% of all chromophobe renal cell carcinoma cases, while metaplastic bone formation is extremely rare.

Case presentation

An abdominal computed tomography scan revealed a hypovascular tumor with focal calcification, measuring 2.5 × 2.3 cm, in the upper pole of the right kidney. The tumor was clinically diagnosed as a right renal cell carcinoma that showed signs of calcification, and a laparoscopic right radical nephrectomy was performed. The cut surface of the tumor was beige in color and indicated that the tumor was an extensively ossified mass. Histological analysis revealed three distinct morphological components of the tumor. The chromophobe renal cell carcinoma consisted of compact epithelial cells arranged in a nested pattern, and these were mixed with extensive areas of sarcomatoid spindle cells with marked nuclear pleomorphism and brisk mitotic activity. The tumor also contained multiple foci of metaplastic ossification.

Conclusion

Chromophobe renal cell carcinoma with concomitant osseous metaplasia and sarcomatoid transformation is a very rare occurrence.