Bilateral multiple renal oncocytomas and cysts associated with a constitutional translocation (8;9)(q24.1;q34.3) and a rare constitutional VHL missense substitution

Potential Role of VHL, PTEN, and BAP1 Mutations in Renal Tumors

The genetic profiling of renal tumors has revealed genomic regions commonly affected by structural changes and a general genetic heterogeneity. The VHL, PTEN, and BAP1 genes are often mutated in renal tumors. The frequency and clinical relevance of these mutations in renal tumors are still being researched. In our study, we investigated VHL, PTEN, and BAP1 genes and the sequencing of 24 samples of patients with renal tumors, revealing that VHL was mutated at a noticeable frequency (25%). Six of the investigated samples showed mutations, and one genetic polymorphism (rs779805) was detected in both heterozygote and homozygote forms. PTEN gene mutation was observed in only one sample, and one specimen showed genetic polymorphism. In the case of the BAP1 gene, all of the samples were wild types. Interestingly, VHL mutation was detected in two female patients diagnosed with AML and in one with oncocytoma. We assume that VHL or PTEN mutations may contribute to the development of human renal cancer. However, the overall mutation rate was low in all specimens investigated, and the development and prognosis of the disease were not exclusively associated with these types of genetic alterations.

Emerging entities in renal cell neoplasia: thyroid-like follicular renal cell carcinoma and multifocal oncocytoma-like tumours associated with oncocytosis

The list of accepted entities of renal cell neoplasia has burgeoned since the turn of the century through recognition of rare tumour types and the discovery of genetic mutations driving renal neoplasia syndromes. This growth has not finished and in this report we present examples of each of these types which were not included in the 2016 World Health Organization classification of renal neoplasia, but are candidates for inclusion in the next edition of the classification. Thyroid-like follicular renal cell carcinoma is a rare tumour type with a distinctive microscopic appearance resembling follicles of the thyroid gland. Thirty-nine cases have been described and the findings have been reasonably consistent. Oncocytoma-like tumours associated with oncocytosis arise as a result of somatic mutations in the mitochondrial genome. The differential diagnosis is mainly with the renal lesions of the Birt-Hogg-Dubé syndrome, which is the result of germline mutations in the folliculin gene. Patients with oncocytoma-like tumours associated with oncocytosis are at great risk of developing renal failure as the proliferating lesions replace the renal parenchyma. Oncocytoma-like tumours have never been found to metastasise.

Advances in the genetics of familial renal cancer

We discuss recent advances in the diagnosis and management of renal cell cancer (RCC) given the enhanced molecular genetics knowledge in this area. A number of hereditary renal cancer syndromes have been described, including von Hippel-Lindau disease, Birt-Hogg-Dubé syndrome, hereditary leiomyomatosis/RCC syndrome, and hereditary papillary renal cancer. Early molecular diagnosis now facilitates the management and prevention of RCC in families. Recommendations for screening in families are discussed.

Pathologic Features of Adult Renal Cortical Tumors

In the past few years, a much better understanding of the morphologic spectrum of renal cortical tumors has resulted in a clinically highly relevant contemporary classification system of these tumors. The current and still evolving era of targeted therapies in kidney cancer further highlights the importance of the appropriate pathologic classification. The recently gained knowledge about molecular-driven antigen expression almost certainly will have a major role to play in the characterization, development, and evaluation of targeted therapies in kidney cancer in the future.

Multiple bilateral renal oncocytoms in a known case of tuberous sclerosis: a case report

One of the rare patterns of renal involvement by tuberous sclerosis is oncocytoma. This is a report of a known male patient diagnosed with tuberous sclerosis. He was asymptomatic, but his periodic abdominal ultrasound examination revealed bilateral renal masses. CT and MRI confirmed the presence of these masses which were proven histopathologically to be multiple oncocytomas.

An 11-bp duplication in the promoter region of the VHL gene in a patient with cerebellar hemangioblastoma and renal oncocytoma

Central nervous system hemangioblastomas are benign vascular tumours that may present sporadically or as manifestation of the von Hippel-Lindau (VHL) disease. VHL Syndrome is a rare autosomal dominant disorder characterized, besides hemangioblastomas, by susceptibility to multifocal and bilateral renal cell carcinoma and cysts, retinal angiomas, pheochromocytoma, epididymis cystoadenoma, pancreatic cysts and/or islet cell tumours. Germline mutations of VHL tumour suppressor gene cause the VHL disease, while somatic mutations have been associated with sporadic hemangioblastomas and clear-cell renal carcinomas. We identified an 11-bp duplication in the promoter region of the VHL gene in a VHL-affected individual. Functional analysis revealed that this variant affects the binding or the binding affinity of one or more transcription factors that regulate the transcription of VHL in vivo, reducing the endogenous levels of VHL mRNA. Moreover, consistent with the "two hits" model, microsatellite analysis of hemangioblastoma tissue from this patient revealed Allelic Imbalance for the chromosomal region near the VHL gene. We propose that these molecular events, through a loss of pVHL function, lead to the onset of the VHL-related tumours in that individual.

Does the finding of a indeterminate mass lesion in screening CT result in kidney loss and is postoperative follow-up necessary in renal encocytomas? A retrospective study

OBJECTIVE

Sixteen patients who were operated on with a preoperative diagnosis of renal tumor were diagnosed with renal oncocytoma between 1991 and 2004. The reliability of preoperative diagnosis, the role of screening CT in organ preservation and the need for follow-up for renal oncocytomas are discussed in the light of literature findings.

MATERIAL AND METHODS

Among 345 patients diagnosed with renal tumors in the previous 13 years, the clinical and radiological features of the 16 patients with renal oncocytomas and the results during the postoperative follow-up period were evaluated in this retrospective study. The female:male ratio was 4.3. Two of the patients complained of hematuria whereas the other 14 experienced lumbocostal pain. The mean dimensions of the tumors on CT scans were 5.7+/-2.88 cm. Central fibrous scarring existed in three patients. Two patients underwent tumor enucleation, three underwent partial nephrectomy and 11 underwent radical nephrectomy.

RESULTS

Screening CT could not achieve a precise preoperative differential diagnosis from malignant renal mass. The organ preservation ratio was approximately 1:3 based on the radiological diagnosis. Screening CT scans showed oncocytomas with diameters greater than those reported in the literature, indicating a need for urgent nephrectomy. No recurrences, metastases or deaths due to renal oncocytoma were observed in the postoperative follow-up period (mean 6.7+/-4 years; range 1-13 years).

CONCLUSIONS

Preoperative diagnosis of renal oncocytoma is very difficult. The postoperative follow-up period in our series was 13 years, which is significantly longer than the duration proposed in the literature.

Multifocal renal oncocytoma in a patient with Von Hippel-Lindau mutation

Von Hippel-Lindau disease (VHL) is a rare genetic disease with a lifetime risk of clear cell renal cell carcinoma in approximately 70% of cases. We present a case of a 63-year-old man with bilateral, multifocal renal masses. Genetic testing results were consistent with a VHL deletion. The patient had no other disease manifestations consistent with VHL. The patient underwent staged bilateral nephron-sparing procedures. Pathology of all renal masses revealed oncocytoma. To our knowledge, we describe the first reported case of multiple renal oncocytomas in a male patient with a germline VHL mutation.

Molecular genetics of familial renal cell carcinoma syndromes

RCC represents a group of clinically and genetically diverse diseases. Familial RCC syndromes, although rare, provide an invaluable model to study the molecular mechanisms of renal carcinogenesis. Many causative oncogenes and tumor suppressor genes have been identified and it is now possible to identify the affected individuals and carriers by genetic testing. Understanding of the molecular pathways of these genes will have a significant impact on the diagnosis and treatment of familial and sporadic RCC.

Familial adult renal neoplasia

Our understanding of the molecular mechanisms underlying the tumorigenesis of renal cell carcinoma (RCC) has partially come from studies of RCC related familial cancer syndromes such as von Hippel-Lindau (VHL) disease and hereditary papillary RCC (HPRC). These studies have led to the identification of RCC related genes, which, besides allowing accurate diagnosis of these diseases, have been found mutated or abnormally expressed in the sporadic counterparts of these familial renal tumours. To date, a number of renal tumour related syndromes have been described. We review recent advances in this field and discuss a genetic approach to managing familial cases of renal tumours occasionally encountered by cancer geneticists and urologists.

Molecular cytogenetic characterization and origin of two de novo duplication 9p cases

We report on two additional cases with duplication of 9p, minor with facial anomalies and developmental delay. Using fluorescence in situ hybridization and single-copy probes, we showed that the first case was a direct duplication, whereas the second case was inverted. The extent of the direct duplication was defined as 9p12 --> p24 by microdissection and microcloning of the aberrant chromosome and subsequent chromosome-specific comparative genomic hybridization. DNA polymorphism analysis with eight microsatellite markers revealed that the origin of the dup(9p) was maternal in the first case, whereas it was paternal in the second.

Inherited carcinomas of the kidney

Studies of families with inherited carcinomas have provided powerful tools to identify the genes involved in the pathogenesis of human cancers. In this review, we summarize the clinical, pathological, and genetic characteristics of the inherited carcinomas of the kidney. We emphasize the observation that different genes predispose to histologically different types of renal carcinoma. Hereditary papillary renal carcinoma, a recently described inherited disorder, is discussed in detail along with the predisposing gene, the MET protooncogene. The data support a classification of renal carcinomas based on molecular genetics.

Familial renal oncocytoma: clinicopathological study of 5 families

PURPOSE

We analyzed familial renal oncocytoma to provide a foundation for studies aimed at defining genes involved in the pathogenesis of renal oncocytoma.

MATERIALS AND METHODS

We describe 5 families with multiple members affected with renal oncocytoma. Tumors were analyzed pathologically, and affected and nonaffected members were screened clinically and genetically.

RESULTS

We identified 12 affected male and 3 affected female (ratio 4:1) individuals in the 5 families. In affected family members renal oncocytomas were often multiple and bilateral. No metastatic disease was observed. Most renal oncocytomas were detected incidentally in asymptomatic individuals or during screening of asymptomatic members of renal oncocytoma families. One identical twin pair was affected with bilateral multiple renal oncocytomas.

CONCLUSIONS

Renal oncocytoma may be inherited in some families.