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

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.

Incidence of renal carcinoma in non-functioning kidney due to renal pelvic stone disease

The objective of This study was to report our pathological findings in nephrectomy specimens from patients treated for non-functioning hydronephrotic kidney due to renal pelvic stone disease. A total of 97 patients who underwent nephrectomy for non-functioning hydronephrotic kidneys between January, 2011 and June, 2014 were retrospectively reviewed. A non-functioning kidney was defined as one having paper-thin parenchyma on urinary ultrasound or computed tomography, exhibiting no contrast visualization in the collecting duct system on intravenous urography and having a split renal function of <10% on nuclear renal function studies. Following pathological evaluation, 9 patients were diagnosed with xanthogranulomatous pyelonephritis, 9 with malignant tumors and 79 with chronic pyelonephritis. Of the patients with chronic pyelonephritis, 2 also had renal adenomas. The malignant tumors included 3 transitional cell carcinomas (TCC), 2 squamous cell carcinomas (SCC), 3 renal cell carcinomas (RCC) (1 sarcomatoid, 1 papillary and 1 clear cell RCC), whereas 1 patient had concurrent RCC and TCC. In conclusion, non-functioning kidneys, particularly those with kidney stones, should be managed as possible malignancies, due to the higher incidence of malignant tumors in such patients compared with the normal population.

A High Association of Upper Urinary Tract Transitional Cell Carcinoma with Nonfunctioning Kidney Caused by Stone Disease in Taiwan

INTRODUCTION

Although many studies have reported that upper urinary tract stones in patients with nonfunctioning kidneys are associated with malignancy, the incidence and frequency of the tumor cell type remain unclear. Therefore, we aimed to investigate the percentage of malignancies present in patients with nonfunctional kidneys who underwent nephrectomy.

MATERIALS AND METHODS

From July 1995 to December 2005, we reviewed a total of 47 patients who underwent nephrectomy to treat a nonfunctional kidney due to urolithiasis with clinical symptoms such as complicated chronic infection. Pathology revealed malignancies in 24 patients. Relationships between clinical presentations and malignancy were analyzed.

RESULTS

Malignancy was diagnosed in 24 patients after nephrectomy. Image studies revealed possible malignancy in only 7 patients before surgery. A high incidence (17/24) of transitional cell carcinoma was noted. The remaining malignancies included 5 renal cell carcinomas, 1 squamous cell carcinoma and 1 epidermoid carcinoma. There were 5 deaths during the follow-up interval.

CONCLUSIONS

There is a high incidence of malignancy associated with nonfunctional kidney caused by stone disease. We suggest careful examination of the pathological specimens from nephrectomy for nonfunctional kidney regardless of clinical manifestations.

Sarcomatoid Renal Cell Carcinoma With Divergent Sarcomatoid Growth Patterns: A Case Report and Review of the Literature

A 71-year-old woman who presented with left abdominal pain was found to have a noncalcified renal mass with a perisplenic extension on imaging studies. Histologically, the tumor showed predominantly malignant spindle cells with extensive osteoid and chondroid matrix production. Various growth patterns resembling rhabdomyosarcoma, malignant fibrous histiocytoma, and fibrosarcoma were also observed. Immunohistochemistry showed positive staining of the neoplastic cells for cytokeratin and focally positive staining for CD10 and CD117 (c-Kit). Electron microscopic examination revealed a poorly differentiated neoplasm with both mesenchymal and epithelial features. The tumor was diagnosed as a sarcomatoid renal cell carcinoma with overgrowth of the sarcomatoid component (World Health Organization: renal cell carcinoma, unclassified). To our knowledge, sarcomatoid renal cell carcinoma with such a broad morphologic phenotype in a single case has not been documented. Furthermore, the CD117 expression in a sarcomatoid renal cell carcinoma that was observed in this case merits further investigation.

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.