Cases of sarcomatoid renal cell carcinoma are very rare. It has been known that sarcomatoid renal cell carcinoma is an epithelial cell variant that has been metaplastically transformed with a very poor prognosis. Diagnosis of sarcomatoid renal cell carcinoma is performed by examining a nephrectomy specimen to see if epithelial and sarcomatoid components are variously mixed together. Therefore, the aim of this paper is to report five cases of sarcomatoid renal cell carcinoma.
Carcinoma, Renal Cell* ; Diagnosis ; Epithelial Cells ; Nephrectomy ; Pathology ; Prognosis

Tubulocystic renal cell carcinoma (TC-RCC) is a recently recognized, rare but distinct malignant entity. Pathologists have endeavored to completely define its histomorphologic, immunohistochemical and molecular features. Recounted is a case where the diagnosis of TC-RCC was confounded by presence of papillary morphology. Immunohistochemical expression of alpha-methyl acyl-CoA-racemase and vimentin with corresponding negativity for CK7 and CD10, following distinctive gross and microscopic findings, confirmed a diagnosis of TC-RCC. This report demonstrates the strategic value of performing immunohistochemistry studies to establish a diagnosis of TC-RCC especially when unusual histologic features are encountered. Immunohistochemistry continues to be the most practical approach to diagnosis as molecular testing methods, such as next generation sequencing, remain unfeasible in the local setting. Cautious prognostication is required as accounts of recurrence and metastasis continue to emerge.
Carcinoma, Renal Cell ; Histology ; Immunohistochemistry ; Diagnosis ; Pathology, Surgical

Adenoma ; pathology ; Carcinoma, Renal Cell ; pathology ; Diagnosis, Differential ; Female ; Humans ; Kidney Neoplasms ; pathology ; Middle Aged

Adult ; Carcinoma, Renal Cell ; diagnosis ; Diagnosis, Differential ; Humans ; Kidney ; pathology ; Kidney Neoplasms ; diagnosis

Atypical carcinoma of the kidney arising from the epithelium of renal collecting duct is a rare disease. Clinical manifestations are mimicking that of the renal cell carcinoma. Diagnosis is confirmed by pathology with immunocytochemical study(cytokeratin) using immunoperoxidase technique. Management is not discussed here. The prognosis is poor with a relatively rapid progression of the disease. We present a case of atypical carcinoma of kidney in a 56 years old male patient with brier review of the literature.
Carcinoma, Renal Cell ; Diagnosis ; Epithelium ; Humans ; Immunoenzyme Techniques ; Kidney* ; Male ; Middle Aged ; Pathology ; Prognosis ; Rare Diseases

Carcinoma, Renal Cell ; classification ; diagnosis ; genetics ; pathology ; Chromosomes, Human ; Humans ; Immunohistochemistry ; methods ; Kidney Neoplasms ; classification ; diagnosis ; genetics ; pathology ; Translocation, Genetic

Epithelioid angiomyolipoma is a recently described rare variant of renal angiomyolipoma. It can occur in patients with or without tuberous sclerosis. We report the imaging findings of a case of epithelioid angiomyolipoma that showed the presence of fatty tissue undifferentiated from the typical angiomyolipoma at the beginning. After partial nephrectomy, tumour recurrence occurred two years later, presenting as completely solid tumours with no adipose tissue, and with invasion into the psoas muscle and left adrenal gland. Differentiation of this tumour from renal cell carcinoma is difficult. Both the radiologist and surgeon should be aware of the existence of this tumour and its potentially malignant behaviour.
Aged ; Angiomyolipoma ; diagnosis ; pathology ; surgery ; Carcinoma, Renal Cell ; diagnosis ; Diagnosis, Differential ; Female ; Humans ; Kidney ; pathology ; Kidney Neoplasms ; diagnosis ; pathology ; surgery ; Neoplasm Recurrence, Local ; pathology ; Tomography, X-Ray Computed

Renal angiomyolipoma (AML) is a common benign tumor in the urinary system, mainly composed of adipose tissue, blood vessels and muscle tissue. Renal AML is sporadic in most of patients, while a few are associated with tuberous sclerosis. Classical renal AML occurs predominantly in middle-aged females. Most cases are found incidentally during imaging examinations. The fat content makes AML have unique imaging characteristics and is easy to be identified with other renal tumors. However, the amount of fat varies in each tumor. AML that contains only microscopically detectable fat and whose amount of intratumoral fat may be too small to be identified on unenhanced computed tomography (CT) images is termed minimal fat or fat-poor renal AML, which appears as a high density shadow in the renal parenchyma on unenhanced CT images. Thus, it can be difficult to distinguish it from renal cell carcinoma (RCC) on imaging. Since the imaging findings are atypical, the diagnosis depends on pathological results. In addition, a few of AML can mimic malignant neoplasms. Recent studies suggested that AML might involve to peri-renal or renal sinus fat, regional lymphatics and other visceral organs, as well as inferior vena cava, which further makes the diagnosis more difficult. However, there is currently no reports about involvement of regional limphatics in minimal fat renal AML. In this article, we report a 27-year-old female patient without family history of tuberous sclerosis, who came to visit the hematologist because a high density shadow near the left kidney was found during CT scan which was accompanied by neck, armpits, groin, abdominal cavity and retroperitoneal lymph nodes enlargement. She was suspected of lymphoma in the beginning and transferred to Department of Urology to perform laparoscopic left renal mass and retroperitoneal lymph node excision and pathological examination for a definitive diagnosis. Finally, pathologic results revealed AML. Postoperative continuous lymphatic fistula developed and the retroperitoneal drainage of chylous fluid was 100-200 mL per day, lasting for 12 weeks. The fistula was successfully closed after conservative treatment including fasting and rehydration. This article summaries and discusses the diagnosis and treatment of renal AML with lymph nodes enlargement and the management of postoperative refractory lymphatic fistula by reviewing the related cases and literature.
Adult ; Angiomyolipoma/pathology* ; Carcinoma, Renal Cell/diagnosis* ; Female ; Fistula ; Humans ; Kidney Neoplasms/pathology* ; Lymph Nodes/pathology* ; Middle Aged

OBJECTIVETo compare the old classification and 2004 WHO histological classification of renal cell carcinoma, summarize the differences and possible reasons, and correct the traditional pathological concepts of kidney cancer.

METHODSSpecimens of 79 cases histopathologically diagnosed as non-clear cell renal cell carcinomas after radical nephrectomy during 1998 to 2005 in Tianjin Medical University Cancer Hospital were reclassified according to the 2004 WHO renal cell carcinoma histological classification system.

RESULTSAfter reclassification, there were 14 cases of clear cell renal cell carcinoma (CCRCC), 23 cases of papillary renal cell carcinoma (PRCC), 34 cases of chromophobe renal cell carcinoma (ChRCC), one collecting duct renal cell carcinoma, one unclassified renal cell carcinoma, 5 cases of mixed cell renal cell carcinoma (CCRCC + PRCC 2 cases, CCRCC + ChRCC 2 cases, PRCC + ChRCC 1 case), and one oncocytoma diagnosed.

CONCLUSIONSSome chromophobe renal cell carcinomas and papillary renal cell carcinomas were easier to be diagnosed as granular cell renal cell carcinoma in the past. The eosinophilic cytoplasm similar to that in the granular cells, and some confusion between PRCC and ChRCC are the main reasons. The cellular characteristic features of granular renal cell carcinoma can be found in many types of renal tumors. Granular cell renal cell carcinoma is not an independent entity, therefore, it should be removed from the histological classification of renal cell carcinoma. The diagnosis standard of mixed renal cell carcinoma (MRCC) need to be determined and consummated.

Adenocarcinoma ; pathology ; Carcinoma, Renal Cell ; classification ; pathology ; Diagnosis, Differential ; Humans ; Kidney Neoplasms ; classification ; pathology ; World Health Organization

OBJECTIVE: To investigate the capabilities of classification models based on hierarchical fusion framework of multi-classifier using a random projection strategy for differentiation of renal cell carcinoma (RCC) from small renal angiomyolipoma (< 4 cm) without visible fat (AMLwvf). METHODS: We retrospectively collected the clinical data from 163 patients with pathologically proven small renal mass, including 118 with RCC and 45 with AMLwvf.Target region of interest (ROI) delineation was performed on an unenhanced phase (UP) CT image slice displaying the largest lesion area.The radiomics features were used to establish a hierarchical fusion method.On the projection-based level, the homogeneous classifiers were fused, and the fusion results were further fused at the classifier-based level to construct a multi-classifier fusion system based on random projection for differentiation of AMLwvf and RCC.The discriminative capability of this model was quantitatively evaluated using 5-fold cross validation and 4 evaluation indexes[specificity, sensitivity, accuracy and area under ROC curve (AUC)].We quantitatively compared this multi-classifier fusion framework against different classification models using a single classifier and several multi-classifier ensemble models. RESULTS: When the projection number was set at 10, the proposed hierarchical fusion differentiation framework achieved the best results on all the evaluation measurements.At the optimal projection number of 10, the specificity, sensitivity, average accuracy and AUC of the multi-classifier ensemble classification system for differentiation between AMLwvf and RCC were 0.853, 0.693, 0.809 and 0.870, respectively. CONCLUSION The proposed model constructed based on a multi-classifier fusion system using random projection shows better performance to differentiate RCC from AMLwvf than the AMLwvf and RCC discrimination models based on a single classification algorithm and the currently available benchmark ensemble methods.
Angiomyolipoma/pathology* ; Carcinoma, Renal Cell ; Diagnosis, Differential ; Humans ; Kidney Neoplasms/pathology* ; Retrospective Studies ; Tomography, X-Ray Computed/methods*