A case of papillary cystadenoma of the epididymis]

BACKGROUND: In AIDS, nodular skin disease can result from various causes. OBJECTIVE: To report a new manifestation of microsporidial infection presenting as nodular skin disease with underlying osteomyelitis. DESIGN: Case report. SETTING: Tertiary-care military medical center in Washington, D.C. PATIENT: A 36-year-old woman with late-stage AIDS who presented with disseminated, nodular cutaneous lesions and underlying osteomyelitis. MEASUREMENTS: Disseminated microsporidial infection with an Encephalitozoon-like species was diagnosed by electron microscopic examination of material obtained from the skin lesions. INTERVENTION: The patient received long-term oral clindamycin therapy, which cured her disseminated infection. CONCLUSIONS: Microsporidia can cause disseminated cutaneous infections in AIDS patients. The response of this patient to long-term clindamycin therapy merits further evaluation.     

von Hippel-Lindau gene deletion detected in the stromal cell component of a cerebellar hemangioblastoma associated with von Hippel-Lindau disease

In adults, lead toxicity is most commonly caused by occupation in a lead industry. Whereas lead toxicity has been described in workers who are involved in bridge rehabilitation, as of this date there has been no systematic evaluation published regarding the conditions responsible for lead toxicity in ironworkers. This is a report of a study designed to identify risk factors for elevated blood-lead levels in ironworkers. One hundred fifty members of a 2,400-member local ironworkers union volunteered to have their blood drawn for lead and zinc protoporphyrin analysis and to complete a questionnaire regarding demographics, health, and occupation. The relationships between these variables and blood-lead level were analyzed using student's t-test, chi-square, and logistic regression. Current work on a lead job, rivet busting as the predominant job task, and cigarette smoking were all found to be significantly associated with elevated blood-lead level. Whereas cigarette smoking and current work with lead have been previously identified as risk factors for toxicity, interventions to prevent lead toxicity in ironworkers should also focus on work practices during rivet busting.     

Papillary cystadenoma of the epididymis. An ultrastructural and immunohistochemical study

Papillary cystadenoma of the epididymis is a rare neoplasm that is sometimes associated with von Hippel-Lindau's syndrome. Electron microscopic study of the present case revealed that neoplastic cells contained abundant glycogen granules and large lipid droplets, but a few organelles. On the apical surface there were numerous microvilli and a few single cilia, but no ciliated cells. Subepithelial basal lamina was noted, but it was occasionally disrupted. Furthermore, microvilli sprang from the circumference of the small tumor-cell nest and became associated with matrix components (microvillus-matrix associations). On immunohistochemical study, neoplastic cells showed epithelial characteristics, but positive reactivity for S-100 protein. These findings resembled those of the epithelial cells of the efferent ductules of the epididymis. In the stroma, prominent vasculature was characteristic and fenestrated-type capillaries were found in the peripheral portion of the tumor. Papillary cystadenoma of the epididymis may originate from non-ciliated epithelial cells of the efferent ductules.     

Somatic mutation in the neonatal mouse

Several mechanisms that diversify the adult immune repertoire, such as terminal deoxynucleotidyl transferase-dependent N region addition, are not available to the neonatal mouse. One important process that contributes to protective immunity in the adult is somatic mutation, which plays a major role in the generation of high affinity memory B cells. It is not clear whether B cells in the neonatal mouse can activate the somatic mutation machinery. To investigate this, we immunized neonates with poly(L-Tyr,L-Glu)-poly-D,L-Ala-poly-L-Lys complexed with methylated BSA, or (4-hydroxy-3-nitrophenyl)acetyl coupled to chicken gamma-globulin. Eight to fourteen days after priming, V(D)J rearrangements of known V(H) genes (V(H)SM7 family) were screened for mutations using a temperature-melt hybridization assay and oligonucleotide probes specific for complementarity-determining regions I and II; possible mutations were confirmed by sequence analysis. More mutations per sequence were found in heavy chains from neonates immunized with (4-hydroxy-3-nitrophenyl)acetyl coupled to chicken gamma-globulin than in those from neonates immunized with poly(L-Tyr,L-Glu)-poly-D,L-Ala-poly-L-Lys complexed with methylated BSA. Mutations were found in heavy chains lacking N regions, suggesting that B cells of the putative fetal lineage can somatically mutate and diversify an initially limited repertoire. Since neonates immunized as early as 1 or 2 days after birth had mutations, the somatic mutation machinery can be activated soon after birth, suggesting that early vaccination should result in affinity maturation and protective immunity in the neonate.     

Renal transplantation in patients with renal cell carcinoma and von Hippel-Lindau disease

This study reviewed the management and outcome of patients with von Hippel-Lindau disease (VHLD) who underwent renal transplantation after being rendered anephric to treat multifocal bilateral renal cell carcinoma (RCC). Five patients with bilateral RCC and VHLD underwent renal transplantation at our hospital. Initial treatment of RCC consisted of bilateral nephrectomy in 2 patients and unilateral nephron-sparing surgery with contralateral nephrectomy in 3 patients. All of the latter 3 patients experienced isolated tumor recurrence in the renal remnant at 48, 64, and 66 months postoperatively; this was managed by complete excision of the renal remnant. Renal transplantation was performed 11 to 24 months after initiation of dialysis. Postoperatively, all of the allografts functioned well with no further requirement for dialysis. Currently, 4 patients are alive at a mean post-transplant follow-up interval of 26 months (range, 7 to 66 months) with excellent graft function and no evidence of malignancy. One patient died 17 months following transplantation due to metastatic disease. Renal transplantation can provide satisfactory replacement therapy for patients with end-stage renal disease with VHLD and treated RCC.     

Down-regulation of transmembrane carbonic anhydrases in renal cell carcinoma cell lines by wild-type von Hippel-Lindau transgenes

To discover genes involved in von Hippel-Lindau (VHL)-mediated carcinogenesis, we used renal cell carcinoma cell lines stably transfected with wild-type VHL-expressing transgenes. Large-scale RNA differential display technology applied to these cell lines identified several differentially expressed genes, including an alpha carbonic anhydrase gene, termed CA12. The deduced protein sequence was classified as a one-pass transmembrane CA possessing an apparently intact catalytic domain in the extracellular CA module. Reintroduced wild-type VHL strongly inhibited the overexpression of the CA12 gene in the parental renal cell carcinoma cell lines. Similar results were obtained with CA9, encoding another transmembrane CA with an intact catalytic domain. Although both domains of the VHL protein contribute to regulation of CA12 expression, the elongin binding domain alone could effectively regulate CA9 expression. We mapped CA12 and CA9 loci to chromosome bands 15q22 and 17q21.2 respectively, regions prone to amplification in some human cancers. Additional experiments are needed to define the role of CA IX and CA XII enzymes in the regulation of pH in the extracellular microenvironment and its potential impact on cancer cell growth.     

Somatic mutation favors the evolution of diploidy

Explanation of diploidy have focused on advantages gained from masking deleterious mutations that are inherited. Recent theory has shown that these explanations are flawed. Indeed, we still lack any satisfactory explanation of diploidy in species that are asexual or that recombine only rarely. Here I consider a possibility first suggested by Efroimson in 1932, by Muller in 1964 and by Crow and Kimura in 1965: diploidy may provide protection against somatic, not inherited, mutations. I both compare the mean fitness of haploid and diploid populations that are asexual and investigate the invasion of "diploidy" alleles in sexual populations. When deleterious mutations are partially recessive and somatic mutation is sufficiently common, somatic mutation provides a clear advantage to diploidy in both asexual and sexual species.     

Bilateral renal carcinoma in von Hippel-Lindau Disease

Von Hippel-Lindau disease, one of the phakomatoses, is believed to be a disorder of mesodermal differentiation. Renal lesions, usually cysts or adenocarcinomas with an occasional hemangioblastoma, occur in approximately two thirds of all patients. The renal neoplasms previously reported have been multiple, bilateral, and usually beyond resection. A thirty-eight-year-old white male with a cerebellar hemangioblastoma and bilateral renal adenocarcinoma underwent suboccipital craniotomy, right heminephrectomy, and left radical nephrectomy. No evidence of recurrent disease can be identified ten months postoperatively. An aggressive approach in this systemic disease appears to be warranted.     

Molecular analysis of the von Hippel-Lindau disease tumor suppressor gene in human lung cancer cell lines

The deletion of the short arm of chromosome 3 is frequently observed in lung cancer. To determine whether the von Hippel-Lindau (VHL) disease tumor suppressor gene located at 3p25 is responsible for oncogenesis in lung cancer, we searched the known open reading frame using the single-strand conformation polymorphism (SSCP) technique for mutations in the VHL gene in 72 cancer cell lines including small cell (SCLC) and non-small cell (NSCLC) lung cancers, carcinoids, and mesotheliomas. SSCP analysis showed that four cell lines have altered SSCP patterns within the coding region and one in an intron of the VHL gene. SCLC line NCI-H1672 had a somatic mutation, G to A at nucleotide (nt) 530, leading to amino acid substitution (glycine to aspartic acid) compared to normal DNA from the same patient. Mesothelioma line NCI-H28 had T to A mutation at nt 479 leading to leucine to histidine amino acid change. We found one frequent polymorphism A (0.72) or G (0.28) at nt 19 resulting in either serine or glycine at this position, changes also found in normal peripheral blood cell DNA, often in a heterozygous state. In addition, we found single rare polymorphisms which did not alter the coding region including: C to G at nt 396, G to T at nt 843, and C to T change in an intron. These results suggest that the VHL gene is only rarely mutated in thoracic malignancies.     

Molecular genetic analysis of von Hippel-Lindau disease

Von Hippel-Lindau (VHL) disease is a dominantly inherited multisystem family cancer syndrome predisposing to retinal and central nervous system haemangioblastomas, renal carcinoma, phaeochromocytoma, pancreatic islet cell tumours and endolymphatic sac tumours. In addition, renal, pancreatic and epididymal cysts occur. Morbidity and mortality from VHL disease can be reduced by the identification and surveillance of affected individuals and at-risk relatives so that complications are diagnosed at an early presymptomatic stage. The detailed mapping and subsequent isolation of the VHL tumour suppressor gene has enabled molecular genetic analysis in families and patients with definite or possible VHL disease. Initially, linked DNA markers were used in informative families to modify individual risks and then to make appropriate alterations in surveillance programs. However, currently most DNA analysis involves the characterisation of germline mutations. World-wide, mutations have been identified in almost 500 families (including 132 in our laboratory). These studies have revealed considerable heterogeneity both in the type and in the location of mutations within the VHL gene. In our experience, most recurrent mutations result from de novo mutations at hypermutable sequences, although a founder effect for the Tyr98His ('Black Forest') mutation has been reported in German and American families. Although many mutations are predicted to impair the ability of pVHL to combine with the elongin regulatory subunits, analysis of genotype-phenotype relationships suggests that the VHL protein has multiple and tissue specific functions. Calculation of tumour risks for different classes of VHL mutations has provided important prognostic information especially with respect to the likelihood of phaeochromocytoma. However, there is evidence that retinal involvement does not correlate with allelic heterogeneity, but that the variability in retinal angiomatosis is influenced by modifier gene effects. VHL gene mutation analysis also provides a basis for investigating the genetic basis of familial phaeochromocytoma and renal cell carcinoma, and apparently isolated retinal angiomas. Results to date suggest that a substantial proportion of patients with familial pheochromocytoma have VHL gene mutations but in contrast, most familial clusters of clear cell renal cell carcinoma (RCC) without evidence of VHL do not have germline VHL mutations.     

Prevalence, morphology and biology of renal cell carcinoma in von Hippel-Lindau disease compared to sporadic renal cell carcinoma

PURPOSE: Renal cell carcinoma occurs as a sporadic tumor but may be part of the autosomal dominant von Hippel-Lindau disease, characterized by retinal and central nervous system hemangioblastoma, pheochromocytoma, pancreatic cysts and renal cell carcinoma. We determine the prevalence of von Hippel-Lindau disease in a series of unselected renal cell carcinoma cases by molecular genetic analysis, and compare sporadic to von Hippel-Lindau renal cell carcinoma with respect to morphology and biology. MATERIALS AND METHODS: We established registers comprising 63 subjects with von Hippel-Lindau renal cell carcinoma, belonging to 30 distinct families (register A), and 460 unselected patients operated on for renal cell carcinoma in an 11-year period (register B). Molecular genetic analysis of the von Hippel-Lindau gene was performed for living patients of register A, representing 80% of von Hippel-Lindau families, and register B, 62% living patients, to identify von Hippel-Lindau germline mutations. In addition, register B was evaluated by a questionnaire (95% response) for familial occurrence of von Hippel-Lindau disease. RESULTS: The prevalence of von Hippel-Lindau renal cell carcinoma was 1.6% in 189 consenting unselected renal cell carcinoma patients. Risk factors for occult germline von Hippel-Lindau gene mutations in register B included familial renal cell carcinoma in 3 of 3 patients (100%), multifocal or bilateral renal cell carcinoma in 1 of 10 (10%) and age younger than 50 years at diagnosis in 1 of 33 (3%). Compared to sporadic von Hippel-Lindau renal cell carcinoma was characterized by an occurrence 25 years earlier, association with renal cysts, multifocal and bilateral tumors, cystic organization and low grade histology, and a better 10-year survival (p < 0.001 each). In von Hippel-Lindau disease metastases occurred only in tumors larger than 7 cm. CONCLUSIONS: von Hippel-Lindau differs from sporadic renal cell carcinoma in morphology and biology. Our data provide arguments for planning surgery for von Hippel-Lindau renal cell carcinoma and should stimulate future investigations.     

Efficacy of gene testing for von Hippel-Lindau disease

OBJECTIVE: To determine the efficacy of genetic testing of individuals presenting with features possibly indicative of von Hippel-Lindau (VHL) disease, regardless of other relevant family and clinical details. SETTING AND PARTICIPANTS: Between September 1994 and December 1997, 16 unrelated individuals were referred to Genetic Services of Western Australia by local clinicians and by similar genetic services in other States, for VHL gene mutation analysis because of clinical manifestations suggestive of the diagnosis. METHODS: The subjects were investigated by screening for mutations in the polymerase chain reaction products of the three VHL gene exons using single-stranded conformational polymorphism analysis (SSCP). If no mutations were detected the exons were sequenced, and if no variations were found DNA was examined by Southern analysis for germinal rearrangements. RESULTS: Mutations in the VHL gene were detected in eight of 16 individuals (50%), including 3 individuals with no family history suggestive of VHL disease. Five mutations were detected by SSCP, two by gene sequencing and one by Southern analysis. Each mutation occurred only in a single family and three had not been previously reported. CONCLUSION: Genetic screening of individuals presenting with clinical features suggestive of VHL facilitates confirmation of the diagnosis, accurate genetic counselling and surveillance of at-risk family members. The necessity for costly and time-consuming screening programs can be reduced and screening directed at those carrying the mutation. Our low stringency criteria are justified for screening for VHL mutations.     

Molecular genetic diagnosis of von Hippel-Lindau disease in familial phaeochromocytoma

Inherited predisposition to phaeochromocytoma is seen in multiple endocrine neoplasia type 2 syndromes, von Hippel-Lindau (VHL) disease, and neuro-fibromatosis type 1. In addition familial phaeochromocytoma alone has been reported. To investigate the genetic basis for familial phaeochromocytoma alone, we screened three affected kindreds for mutations in the RET proto-oncogene and the VHL tumour suppressor gene. We did not detect MEN 2 associated RET mutations in any family, but missense VHL gene mutations (V155L and R238W) were identified in two kindreds with no clinical evidence of VHL disease. Patients with familial, multiple, or early onset phaeochromocytoma should be investigated for germline VHL and RET gene mutations as the molecular diagnosis of multisystem familial cancer syndromes enables appropriate counselling and screening to be provided.     

Independent segregation of von Hippel-Lindau disease and cerebral cavernomas

A probable diagnosis of von Hippel-Lindau disease was made in a two generation family in which the proband had a phaeochromocytoma, renal cysts, and multiple cerebral cavernomas. His sister had multiple similar cerebral vascular lesions and his father died from renal carcinoma aged 42. Although the family did not satisfy the conventional diagnostic criteria for von Hippel-Lindau disease, an underlying germline mutation in the von Hippel-Lindau disease tumour suppressor gene was identified in the proband. Molecular genetic analysis not only confirmed the putative diagnosis of the disease in the proband but also showed that the cerebral vascular lesions segregated independently from the von Hippel-Lindau disease mutation. This report exemplifies how molecular genetic investigations can enhance the diagnosis and management of families with suspected von Hippel-Lindau disease, particularly when the manifestations, as in this family, are not typical.     

von Hippel-Lindau gene mutations in N-nitrosodimethylamine-induced rat renal epithelial tumors

BACKGROUND: Mutations in the von Hippel-Lindau (VHL) gene are common in human clear cell kidney cancers. Carcinogens in cigarette smoke, especially nitrosamines, are known to induce kidney tumors of a variety of histologic types in rodents--but with no evidence of VHL mutations; however, none of these tumors resembled human clear cell carcinomas. We examined N-nitrosodimethylamine-induced kidney tumors of the clear or mixed clear/granular cell type in Wistar rats to assess the presence of VHL mutations. METHODS: Sections of eight clear or mixed clear/granular cell kidney tumors that had been formalin fixed and paraffin embedded were microdissected. DNA was extracted from the microdissected tissue, and exons 1-3 of the rat VHL gene were examined by use of polymerase chain reaction and cycle sequencing techniques. RESULTS: Four VHL gene mutations (three G:C to A:T and one A:T to G:C) were detected in three of the tumors in contrast to no mutations in 40 previously reported rat kidney tumors of other histologic types (three of eight tumors versus none of 40; two-sided Fisher's exact test; P=.003). Only tumors showing prominent swollen clear cell cytology with a signet-ring appearance had VHL mutations. CONCLUSIONS: To our knowledge, this is the first report of VHL mutations in kidney tumors after direct chemical exposure and provides a possible molecular pathway linking tobacco smoking to kidney cancer.     

Putative control of angiogenesis in hemangioblastomas by the von Hippel-Lindau tumor suppressor gene

The hypoxia-inducible endothelial cell-specific mitogen vascular endothelial growth factor/vascular permeability factor (VEGF/VPF) is expressed in low amounts in adult human brain, but is highly upregulated in the perinecrotic palisading cells of glioblastomas. We observed high VEGF expression in cerebellar hemangioblastomas, which are highly vascular, nonnecrotic and presumably nonhypoxic tumors, and hypothesized that a mechanism other than hypoxia leads to VEGF upregulation. Because hemangioblastomas develop in patients with von Hippel-Lindau disease, and mutations of the von Hippel-Lindau tumor suppressor (VHL) gene have also been reported in sporadic hemangioblastomas, we investigated VHL expression in normal cerebellum and in hemangioblastomas and tested the hypothesis that mutations in the VHL gene lead to upregulation of VEGE We observed constitutive expression of VHL mRNA, but downregulation of VEGF mRNA in the postnatal cerebellum. In the adult cerebellum, VHL is predominantly expressed in neuronal cells. In hemangioblastomas, VHL expression appears to be restricted to stromal cells, suggesting that the neoplastic component is the stromal cell. VHL-deficient renal cell carcinoma cells (786-0) produced significantly higher levels of VEGF mRNA and protein compared with 786-0/ wt10 cells, which were stably transfected with the wild-type VHL gene. Our observations suggest that VHL mutations affect stromal cells in hemangioblastomas and that VEGF is upregulated in stromal cells as a consequence of mutations in the VHL gene.     

Treatment of hemangioblastomas in von Hippel-Lindau disease with linear accelerator-based radiosurgery

OBJECTIVE: Stereotactic radiosurgery is increasingly being used to treat hemangioblastomas, particularly those that are in surgically inaccessible locations or that are multiple, as is common in von Hippel-Lindau disease. The purpose of this study was to retrospectively evaluate the effectiveness of radiosurgery in the treatment of hemangioblastomas. METHODS: From 1989 to 1996, 29 hemangioblastomas in 13 patients with von Hippel-Lindau disease were treated with linear accelerator-based radiosurgery. The mean patient age was 40 years (range, 31-57 yr). The radiation dose to the tumor periphery averaged 23.2 Gy (range, 18-40 Gy). The mean tumor volume was 1.6 cm3 (range, 0.07-65.4 cm3). Tumor response was evaluated in serial, contrast-enhanced, computed tomographic and magnetic resonance imaging scans. The mean follow-up period was 43 months (range, 11-84 mo). RESULTS: Only one (3%) of the treated hemangioblastomas progressed. Five tumors (17%) disappeared, 16 (55%) regressed, and 7 (24%) remained unchanged in size. Five of nine patients with symptoms referable to treated hemangioblastomas experienced symptomatic improvement. During the follow-up period, one patient died as a result of progression of untreated hemangioblastomas in the cervical spine. Three patients developed radiation necrosis, two of whom were symptomatic. CONCLUSION: Although follow-up monitoring is limited, stereotactic radiosurgery provides a high likelihood of local control of hemangioblastomas and is an attractive alternative to multiple surgical procedures for patients with von Hippel-Lindau disease.