Differential expression of erythropoietin and its receptor in von hippel-lindau-associated and multiple endocrine neoplasia type 2-associated pheochromocytomas.

Pheochromocytoma is a neuroendocrine tumor associated with a variety of genetic disorders, which include von Hippel-Lindau disease (VHL), multiple endocrine neoplasia type 2 (MEN 2), neurofibromatosis type 1, hereditary paraganglioma, and succinate dehydrogenase gene-related tumors. Previous studies of VHL-associated and MEN 2-associated pheochromocytomas suggest morphological, biochemical, and clinical differences exist among the tumors, but the process by which they develop remains unclear. Studies in other VHL-associated tumors suggest that VHL gene deficiency causes coexpression of erythropoietin (Epo) and its receptor (Epo-R), which facilitates tumor growth. The objective of this study was to understand the different process of tumorigenesis for VHL and MEN 2-associated pheochromocytomas. Ten pheochromocytomas (VHL patients n = 5, MEN 2 patients n = 5) were examined for the presence or absence of Epo and Epo-R using Western blot, immunohistochemistry, and RT-PCR analyses. Coexpression of Epo and Epo-R was found in all five VHL-associated pheochromocytomas; in contrast, expression of Epo-R, but not Epo, was documented in all five MEN 2-associated pheochromocytomas. Expression of Epo appears to be a result of VHL gene deficiency, possibly through activation of the hypoxia inducible factor-1 pathway, whereas Epo-R is an embryonal marker whose sustained expression in both VHL- and MEN 2-associated pheochromocytomas reflects an arrest or defect in development. These findings suggest an alternative process of tumorigenesis in VHL- and MEN 2-associated pheochromocytomas and implicate Epo as a clinical biomarker to differentiate these tumors.

Genetic basis of cancer of the kidney: disease-specific approaches to therapy.

Studies during the past two decades have shown that kidney cancer is not a single disease; it is made up of a number of different types of cancer that occur in this organ. Clear cell renal carcinoma is characterized by mutation of the VHL gene. The VHL gene product forms a heterotrimeric complex with elongin C, elongin B, and Cul-2 to target hypoxia-inducible factors 1 and 2alpha for ubiquitin-mediated degradation. VHL-/- clear cell renal carcinoma overexpresses epidermal growth factor receptor and transforming growth factor alpha. Both hypoxia-inducible factor 1alpha and the epidermal growth factor receptor are potential therapeutic targets in clear cell renal carcinoma. Studies of the hereditary form of renal cell carcinoma (RCC) associated with hereditary papillary renal carcinoma (HPRC) determined that the c-Met proto-oncogene on chromosome 7 is the gene for HPRC and for a number of sporadic papillary RCCs. The HPRC c-Met mutations are activating mutations in the tyrosine kinase domain of the gene. The gene for a new form of hereditary RCC (Birt Hogg Dubé syndrome) associated with cutaneous tumors, lung cysts, and colon polyps or cancer has recently been identified. Studies are currently under way to determine what type of gene BHD is and how damage to this gene leads to kidney cancer. Individuals affected with hereditary leiomyomatosis renal cell carcinoma are at risk for the development of cutaneous leiomyomas, uterine leiomyomas (fibroids), and type 2 papillary RCC. The HLRC gene has been found to be the Krebs cycle enzyme, fumarate hydratase. Studies are under way to understand the downstream pathway of this cancer gene.

Solid renal tumor severity in von Hippel Lindau disease is related to germline deletion length and location.

von Hippel Lindau disease (VHL) is an autosomal dominant familial cancer syndrome linked to alteration of the VHL tumor suppressor gene. Affected patients are predisposed to develop pheochromocytomas and cystic and solid tumors of the kidney, CNS, pancreas, retina, and epididymis. However, organ involvement varies considerably among families and has been shown to correlate with the underlying germline alteration. Clinically, we observed a paradoxically lower prevalence of renal cell carcinoma (RCC) in patients with complete germline deletion of VHL. To determine if a relationship existed between the type of VHL deletion and disease, we retrospectively evaluated 123 patients from 55 families with large germline VHL deletions, including 42 intragenic partial deletions and 13 complete VHL deletions, by history and radiographic imaging. Each individual and family was scored for cystic or solid involvement of CNS, pancreas, and kidney, and for pheochromocytoma. Germline deletions were mapped using a combination of fluorescent in situ hybridization (FISH) and quantitative Southern and Southern blot analysis. An age-adjusted comparison demonstrated a higher prevalence of RCC in patients with partial germline VHL deletions relative to complete deletions (48.9 vs. 22.6%, p=0.007). This striking phenotypic dichotomy was not seen for cystic renal lesions or for CNS (p=0.22), pancreas (p=0.72), or pheochromocytoma (p=0.34). Deletion mapping revealed that development of RCC had an even greater correlation with retention of HSPC300 (C3orf10), located within the 30-kb region of chromosome 3p, immediately telomeric to VHL (52.3 vs. 18.9%, p <0.001), suggesting the presence of a neighboring gene or genes critical to the development and maintenance of RCC. Careful correlation of genotypic data with objective phenotypic measures will provide further insight into the mechanisms of tumor formation.

Utility of plasma free metanephrines for detecting childhood pheochromocytoma.

Measurements of plasma free metanephrines, normetanephrine (NMN) and metanephrine (MN), provide a sensitive test for diagnosis of pheochromocytoma in adults but have not been evaluated in children. We therefore established reference ranges for plasma and urinary metanephrines and the catecholamines, norepinephrine (NE) and epinephrine (E), in 86 healthy children (age 5-17). A group of 158 healthy adults (age 18-72) served as a comparison group. Pediatric reference ranges were applied to examine the diagnostic utility of the various tests in 45 children evaluated for pheochromocytoma (age 8-17; 38 with von Hippel-Lindau syndrome), with tumors found on 12 occasions. Upper reference limits for E and MN were higher and those for NE and NMN lower in children than in adults. Boys had higher plasma levels of E and MN and higher urinary excretion of all four amines than girls. Plasma free metanephrines provided a diagnostic test with values for sensitivity (100%) and specificity (94%) that were equal to or higher than those of other tests. In two children screened for pheochromocytoma on multiple occasions, use of pediatric reference ranges for plasma free metanephrines indicated the tumor a year earlier than indicated using adult reference ranges. The findings indicate that plasma free metanephrines provide a sensitive tool for detection of pheochromocytoma in children. Age appropriate reference ranges should be used and gender differences should be considered.

Biochemical diagnosis of pheochromocytoma: how to distinguish true- from false-positive test results.

Measurements of plasma normetanephrine and metanephrine provide a highly sensitive test for diagnosis of pheochromocytoma, but false-positive results remain a problem. We therefore assessed medication-associated false-positive results and use of supplementary tests, including plasma normetanephrine responses to clonidine, to distinguish true- from false-positive results. The study included 208 patients with pheochromocytoma and 648 patients in whom pheochromocytoma was excluded. Clonidine-suppression tests were carried out in 48 patients with and 49 patients without the tumor. Tricyclic antidepressants and phenoxybenzamine accounted for 41% of false-positive elevations of plasma normetanephrine and 44-45% those of plasma and urinary norepinephrine. High plasma normetanephrine to norepinephrine or metanephrine to epinephrine ratios were strongly predictive of pheochromocytoma. Lack of decrease and elevated plasma levels of norepinephrine or normetanephrine after clonidine also confirmed pheochromocytoma with high specificity. However, 16 of 48 patients with pheochromocytoma had normal levels or decreases of norepinephrine after clonidine. In contrast, plasma normetanephrine remained elevated in all but 2 patients, indicating more reliable diagnosis using normetanephrine than norepinephrine responses to clonidine. Thus, in patients with suspected pheochromocytoma and positive biochemical results, false-positive elevations due to medications should first be eliminated. Patterns of biochemical test results and responses of plasma normetanephrine to clonidine can then help distinguish true- from false-positive results.

Renal tumors in the Birt-Hogg-Dubé syndrome.

Birt-Hogg-Dubé (BHD) syndrome is an autosomal dominant genodermatosis characterized by the development of small dome-shaped papules on the face, neck, and upper trunk (fibrofolliculomas). In addition to these benign hair follicle tumors, BHD confers an increased risk of renal neoplasia and spontaneous pneumothorax. To date, there has been no systematic pathologic analysis of the renal tumors associated with this syndrome. We reviewed 130 solid renal tumors resected from 30 patients with BHD in 19 different families. Preoperative computed tomography scans demonstrated a mean of 5.3 tumors per patient (range 1-28 tumors), the largest tumors averaging 5.7 cm in diameter (+/- 3.4 cm, range 1.2-15 cm). Multiple and bilateral tumors were noted at an early age (mean 50.7 years). The resected tumors consisted predominantly of chromophobe renal cell carcinomas (44 of 130, 34%) or of hybrid oncocytic neoplasms that had areas reminiscent of chromophobe renal cell carcinoma and oncocytoma (65 of 130, 50%). Twelve clear cell (conventional) renal carcinomas (12 of 130, 9%) were diagnosed in nine patients. These tumors were on average larger (4.7 +/- 4.2 cm) than the chromophobe (3.0 +/- 2.5 cm) and hybrid tumors (2.2 +/- 2.4 cm). Microscopic oncocytosis was found in the renal parenchyma of most patients, including the parenchyma of five patients with evidence of clear cell renal cell carcinoma. Our findings suggest that microscopic oncocytic lesions may be precursors of hybrid oncocytic tumors, chromophobe renal cell carcinomas, and perhaps clear cell renal cell carcinomas in patients with BHD syndrome. Recognition by the pathologist of the unusual renal tumors associated with BHD may assist in the clinical diagnosis of the syndrome.

New therapeutic and surgical approaches for sporadic and hereditary pheochromocytoma.

Pheochromocytoma is a rare, surgically correctable cause of hypertension. Modern medical blockade has significantly improved patient survival and morbidity. The last decade has seen the identification of the genes responsible for several hereditary causes of pheochromocytoma. Evaluation of these patients has demonstrated different catecholamine profiles associated with the different syndromes. Genetic testing and new, more sensitive catecholamine tests are allowing better, earlier diagnosis of affected patients. Some patients with small tumors deemed nonfunctional by traditional methods may be safely observed until function is demonstrated. Laparoscopic surgery has supplanted the use of open surgery in the management of these tumors. Adrenocortical-sparing surgery may be performed using laparoscopy in patients with hereditary forms of pheochromocytoma.

Hereditary kidney cancer.

Significant advances have been made in the understanding of the genetic basis of familial renal neoplasia. Identification of key genes in the pathogenesis of various hereditary renal cancer syndromes has provided opportunities to screen family members at risk and to explore the significance of these genetic abnormalities in the development and genesis of much more common sporadic counterparts. As researchers continue to delineate critical carcinogenic pathways and accumulate expansive knowledge on oncogenic mechanisms driving cancer initiation and progression at the cellular and molecular levels, this information will be integrated and translated into effective diagnostic and therapeutic strategies that will dictate clinical management of all renal cancers.

Surgical management of lumbosacral nerve root hemangioblastomas in von Hippel-Lindau syndrome.

OBJECT: Hemangioblastomas in the lumbosacral region are rare, and the authors of prior reports have not defined the surgical management, histopathological features, or outcome in a group of patients after resection of these tumors. To identify features that will help guide the operative and clinical management of these lesions, the authors reviewed data obtained in a series of patients with von Hippel-Lindau syndrome who underwent resection of lumbosacral nerve root hemangioblastomas. METHODS: Six consecutive patients (three men and three women; mean age at surgery 39 years [range 31-48 years]) who underwent operations for resection of lumbosacral nerve root hemangioblastomas were included in this study. The mean follow-up period was 23 months (range 6-45 months). Data derived from examination, hospital charts, operative findings, histopathological analysis, and magnetic resonance imaging were used to analyze surgical management and clinical outcome. The resected tumors were located in the lumbar (five cases) or sacral (one case) regions; the mean tumor size was 2728 mm3 (range 80-15,022 mm3). Consistent with central nervous system (CNS) regional variation of space available to accommodate the neural compressive effect of the hemangioblastoma size, the mean tumor volume (2728 mm3) of these symptomatic lesions was much larger than that of symptomatic hemangioblastomas resected in the other regions of the CNS. Histopathological examination showed infiltration of the associated nerve root by the hemangioblastoma in each case. In five of the six patients complete resection was achieved, and in one patient intradural exploration of two hemangioblastomas was performed, but resection was not achieved because of motor root involvement. In all cases involving complete resections the patients experienced symptomatic improvement. CONCLUSIONS: Lumbosacral nerve root hemangioblastomas can be safely removed in most patients with von Hippel-Lindau syndrome. Generally, hemangioblastomas of the lumbosacral nerve roots should be resected when they become symptomatic. Because these neoplasms appear to originate from the nerve root, it is necessary to sacrifice the nerve root from which the hemangioblastoma originates to achieve complete resection.

Specimen morcellation after laparoscopic radical nephrectomy: confirmation of histologic diagnosis using needle biopsy.

BACKGROUND AND PURPOSE: Laparoscopic radical nephrectomy (LRN) is being increasingly offered for the management of renal-cell carcinoma (RCC). Specimen removal may be performed through a small or hand-port incision or by specimen morcellation. Limited studies exist addressing the accuracy of histopathologic diagnosis in morcellated renal tumors. Because of concerns about the lack of a diagnosis secondary to the morcellation process, we performed premorcellation needle biopsies to obtain nondisrupted tissue for pathologic analysis. Herein, we compare the histopathologic diagnosis achieved via needle biopsy prior to morcellation with that of the final specimen. PATIENTS AND METHODS: Following successful laparoscopic resection, specimens were entrapped in a Lapsac. Needle biopsies were performed manually through the mouth of the Lapsac, and morcellation was then done in some patients using manual and mechanical methods. The histopathologic diagnoses in the needle biopsy specimens and the morcellated material were compared. RESULTS: Laparoscopic radical nephrectomy with specimen morcellation was performed in 15 patients. Nine patients had premorcellation needle biopsies. Eight of these biopsies had sufficient tissue for diagnosis of RCC. This finding correlated with final diagnosis from the morcellated material. Perinephric fat invasion was identified in three morcellated specimens. CONCLUSIONS: Needle biopsy prior to specimen morcellation confirmed the histologic diagnosis of the morcellated specimen. This finding suggests that such histopathology material is adequate for diagnosis and may make premorcellation needle biopsy redundant.

Pheochromocytoma in von hippel-lindau disease: distinct histopathologic phenotype compared to pheochromocytoma in multiple endocrine neoplasia type 2.

Pheochromocytomas are rare neuroendocrine tumors that arise from chromaffin tissue. In a small subset of patients, pheochromocytomas occur as a manifestation of von Hippel- Lindau (VHL) disease. The histology of VHL-associated pheochromocytomas has not been reported in detail. In this article, we describe histopathologic features of 14 pheochromocytomas in eight patients with VHL disease and demonstrate that VHL-associated pheochromocytomas have a distinct histologic phenotype as compared with pheochromocytomas in patients with multiple endocrine neoplasia type 2 (MEN 2). VHL tumors are characterized by a thick vascular tumor capsule; myxoid and hyalinized stroma; round, small to medium tumor cells intermixed with small vessels; predominantly amphophilic and clear cytoplasm; absence of cytoplasmic hyaline globules; and lack of nuclear atypia or mitoses. In contrast to MEN 2, there is no extratumoral adrenomedullary hyperplasia in the VHL adrenal gland. Our findings of a distinct histologic phenotype of VHL pheochromocytoma may further help in subdividing patients who clinically present with multiple, bilateral pheochromocytomas.

Transperitoneal laparoscopic radical nephrectomy for bulky renal tumors.

Laparoscopic management of kidney cancer is becoming accepted as an alternative to open radical nephrectomy. Technical considerations have limited the application of laparoscopic radical nephrectomy to relatively small, clinically localized tumors. At the National Cancer Institute, we have broadened the indications to include bulky tumors. Herein, we describe the operation with attention to the technical caveats that have been gained with experience.

Management of von Hippel-Lindau-associated kidney cancer.

Von Hippel-Lindau disease (VHL) is an autosomal-dominant inherited condition that predisposes patients to develop renal cysts and tumors, most commonly in the second to fourth decades of life. Renal cysts and tumors have historically been a major cause of disease-related morbidity and mortality, so urologists are often called on to manage patients with VHL. Knowledge of the extrarenal manifestations of VHL (hemangioblastomas of the central nervous system and retina, endolymphatic sac tumors, pancreatic cysts, epididymal and broad-ligament cysts, and pheochromocytomas) and integration of nonurologic specialties into management teams for VHL patients will help to achieve successful outcomes. Screening for renal manifestations of VHL, by regular imaging of the abdomen, begins late in the second decade of life. Because renal tumors in VHL can be multifocal and bilateral, management can be complex. Radical nephrectomy removes all tissue at risk for forming renal tumors; however, this necessitates renal replacement therapy. In an effort to control cancer effectively while preserving native renal function and minimizing intervention, some researchers have proposed an observational strategy. Patients are screened until the largest tumor reaches 3 cm in diameter, at which time operative intervention is recommended. Nephron-sparing surgery is undertaken, whenever technically feasible, with the goal of removing all tumors in that renal unit. The role of minimally invasive technologies is currently being evaluated in selected patients with VHL renal masses. Elucidation of molecular pathways associated with VHL renal tumors may facilitate development of effective medical treatments for these lesions in the future.

Partial adrenalectomy: the National Cancer Institute experience.

OBJECTIVES: To report our experience of partial adrenalectomy and demonstrate whether adrenal function can be preserved in patients with hereditary adrenal pheochromocytoma. Total adrenalectomy has largely been used in the treatment of patients with hereditary adrenal pheochromocytomas. Adrenal cortical-sparing surgery is an alternative approach that aims to balance tumor removal with preservation of adrenocortical function. METHODS: From 1995 to 2004, 33 patients with hereditary pheochromocytoma presented with adrenal masses. Partial adrenalectomy (open or laparoscopic) was performed if normal adrenocortical tissue was evident on preoperative imaging or intraoperative ultrasonography. Various operative parameters, as well as postoperative function of the residual adrenal remnants, were determined. RESULTS: Of the 33 patients, 8 underwent open partial adrenalectomy and 25 laparoscopic partial adrenalectomy during a 10-year period. Ten patients underwent simultaneous, bilateral partial adrenalectomy and 8 underwent surgery on a solitary adrenal gland, 4 of whom received postoperative steroid replacement (stopped in 3 after 1 to 3 months). All other patients had normal catecholamine levels and remained tumor free by imaging at a mean follow-up of 36 months (range 3 to 102). CONCLUSIONS: Partial adrenalectomy can preserve adrenal function in patients with adrenal masses. The laparoscopic approach is technically safe and associated with less morbidity without compromising tumor removal. With careful surgical planning, especially in patients with tumors in solitary glands, adrenocortical function may be preserved, thereby avoiding the morbidity associated with medical adrenal replacement.

Metastatic renal cell carcinoma to contralateral ureter presenting as acute obstructive renal failure after radical nephrectomy.

Metastatic renal cell carcinoma commonly involves the lungs, bone, liver, adrenal glands, and brain. Less commonly affected organs include the gallbladder, thyroid, and pancreas. Even metastatic spread to the contralateral kidney and the bladder has been reported. Computed tomography is the standard imaging technique to evaluate for contralateral involvement. One of the disadvantages of computed tomography as a screening modality is its difficulty in identifying small ureteral lesions. We report a rare case of metastatic renal cell carcinoma in the contralateral ureter presenting as acute obstructive renal failure after radical nephrectomy.

Pheochromocytoma catecholamine phenotypes and prediction of tumor size and location by use of plasma free metanephrines.

BACKGROUND: Measurements of plasma free metanephrines (normetanephrine and metanephrine) provide a useful test for diagnosis of pheochromocytoma and may provide other information about the nature of these tumors. METHODS: We examined relationships of tumor size, location, and catecholamine content with plasma and urinary metanephrines or catecholamines in 275 patients with pheochromocytoma. We then prospectively examined whether measurements of plasma free metanephrines could predict tumor size and location in an additional 16 patients. RESULTS: Relative proportions of epinephrine and norepinephrine in tumor tissue were closely matched by relative increases of plasma or urinary metanephrine and normetanephrine, but not by epinephrine and norepinephrine. Tumor diameter showed strong positive relationships with summed plasma concentrations or urinary outputs of metanephrine and normetanephrine (r = 0.81 and 0.77; P <0.001), whereas relationships with plasma or urinary catecholamines were weaker (r = 0.41 and 0.44). All tumors in which increases in plasma metanephrine were >15% of the combined increases of normetanephrine and metanephrine either had adrenal locations or appeared to be recurrences of previously resected adrenal tumors. Measurements of plasma free metanephrines predicted tumor diameter to within a mean of 30% of actual diameter, and high plasma concentrations of free metanephrine relative to normetanephrine accurately predicted adrenal locations. CONCLUSIONS: Measurements of plasma free metanephrines not only provide information about the likely presence or absence of a pheochromocytoma, but when a tumor is present, can also help predict tumor size and location. This additional information may be useful for clinical decision-making during tumor localization procedures.

Evaluation and management of renal tumors in the Birt-Hogg-Dubé syndrome.

PURPOSE: Herein we describe the evaluation and management of renal tumors in Birt-Hogg-Dubé (BHD), an autosomal dominant disorder predisposing to cutaneous fibrofolliculomas, pulmonary cysts, spontaneous pneumothorax and renal tumors. MATERIALS AND METHODS: A total of 124 affected individuals underwent comprehensive clinical evaluation, including body computerized tomography, to determine cutaneous, pulmonary and renal manifestations of BHD. Of these individuals 14 had their renal tumors managed at our institution. RESULTS: Of the 124 BHD affected individuals 34 (27%) had renal tumors of various histologies, most commonly hybrid oncocytic tumor and chromophobe renal carcinoma. Average age at renal tumor detection was 50.4 years and multiple tumors were found in a majority of patients. Some patients with renal tumors were identified that did not have the characteristic cutaneous hallmarks of BHD. In 4 of the 14 patients treated at our institution small (less than 3 cm) renal tumors were observed, while 10 others underwent a total of 12 renal procedures, including 4 radical and 8 partial nephrectomies. At a median of 38 months of followup 5 of these 10 patients remained free of disease, 3 had small renal tumors and 2 died of metastatic renal cancer. CONCLUSIONS: Patients with BHD are at risk for multiple renal tumors that are often malignant and can metastasize. Individuals at risk or affected by BHD should be radiographically screened for renal tumors at periodic intervals and they are best treated with nephron sparing surgical approaches. Genetic testing for this syndrome is now available.

High frequency of somatic frameshift BHD gene mutations in Birt-Hogg-Dubé-associated renal tumors.

The Birt-Hogg-Dubé (BHD) syndrome is an inherited genodermatosis characterized by a predisposition to hamartomatous skin lesions, pulmonary cysts, and renal carcinoma. Seventy-seven renal tumors from 12 patients with germline BHD mutations were examined by DNA sequencing to identify somatic mutations in the second copy of BHD. Sequence alterations were detected in the majority of renal tumors (41 of 77, 53%), with loss of heterozygosity at the BHD locus in a minority of additional tumors (14 of 77, 17%). The somatic mutations were distributed across the entire gene, and the majority resulted in frameshifts that are predicted to truncate the BHD protein. These results support a role for BHD as a tumor suppressor gene that predisposes to the development of renal tumors when both copies are inactivated.

Germline BHD-mutation spectrum and phenotype analysis of a large cohort of families with Birt-Hogg-Dubé syndrome.

Birt-Hogg-Dubé syndrome (BHD), a genodermatosis characterized by multiple hamartomas of the hair follicle (fibrofolliculoma), predisposes individuals to an increased risk of developing renal neoplasms and spontaneous pneumothorax. Previously, we localized the BHD locus (also known as FLCN) to chromosome 17p11.2 by linkage analysis and subsequently identified germline mutations in a novel gene in probands from eight of the nine families with BHD in our screening panel. Affected members of five of the families inherited an insertion/deletion of a cytosine in a C8 tract in exon 11. This mutation was also identified by exon 11 screening in probands from 22 of 52 additional families with BHD and therefore represents a hypermutable "hotspot" for mutation in BHD. Here, we screened the remaining 30 families from this large BHD cohort by direct sequence analysis and identified germline BHD mutations in 84% (51/61) of all families with BHD recruited to our study. Mutations were located along the entire length of the coding region, including 16 insertion/deletion, 3 nonsense, and 3 splice-site mutations. The majority of BHD mutations were predicted to truncate the BHD protein, folliculin. Among patients with a mutation in the exon 11 hotspot, significantly fewer renal tumors were observed in patients with the C-deletion than those with the C-insertion mutation. Coding-sequence mutations were not found, however, in probands from two large families with BHD whose affected members shared their family's BHD-affected haplotype. Of the 53 families with BHD whose members inherited either a germline mutation or the affected haplotype, 24 (45%) had at least one member with renal neoplasms. Three families classified with familial renal oncocytoma were identified with BHD mutations, which represents the first disease gene associated with this rare form of renal neoplasm. This study expands the BHD-mutation spectrum and evaluates genotype-phenotype correlations among families with BHD.

Update on minimally invasive approaches to kidney tumors.

Renal tumors are being detected at increasing rates because of widespread use of modern imaging techniques such as ultrasonography and computed tomography. Typically, these tumors, many of which are discovered incidentally, tend to be small and are confined to the kidney. Advances in ablative and imaging technology have led to the application of minimally invasive therapy in the treatment of small renal tumors. Although still evolving as a cancer treatment, minimally invasive treatment potentially offers several advantages over conventional open renal surgery: shorter convalescence, improved cosmesis, reduced postoperative pain, and renal preservation. This article reviews the status and recent progress of minimally invasive approaches to renal neoplasm.