Allelic deletions of the VHL gene detected in multiple microscopic clear cell renal lesions in von Hippel-Lindau disease patients.

Patients with von Hippel-Lindau (VHL) disease develop a spectrum of bilateral clear-cell renal lesions including cysts and renal cell carcinomas (RCCs). VHL gene deletions have been previously reported in VHL-associated macroscopic RCC. Although histological analysis suggests that microscopic cystic lesions in the VHL patients may represent precursors of the RCC, there is at present no direct molecular evidence of their relationship. To investigate the relationship between cystic lesions and RCC, 26 microdissected archival renal lesions from two VHL disease patients were studied for loss of heterozygosity at the VHL gene locus using polymerase chain reaction single-strand conformation polymorphism analysis. The renal lesions included 2 benign cysts, 5 atypical cysts, 5 microscopic RCCs in situ, 5 cysts lined by a single layer of cells, in which RCCs in situ were developing, and 2 microscopic and 7 macroscopic RCCs. Except for a single benign cyst, 25 of 26 renal lesions showed nonrandom allelic loss of the VHL gene. In either of the 2 patients, the same VHL allele was deleted in all of the lesions tested, indicating loss of the wild-type allele and retention of the inherited, mutated VHL allele. The results suggest that all clear-cell lesions in the VHL kidney represent neoplasms and that the loss of the VHL gene occurs early in their development. Atypical and benign cysts most likely represent the initial phenotype in malignant transformation to the RCC.     

Comparison of epigenetic and genetic alterations in mucinous cystic neoplasm and serous microcystic adenoma of pancreas.

Mucinous cystic neoplasms and serous microcystic adenomas account for the majority of cystic tumors of pancreas. Mucinous cystic neoplasms and serous microcystic adenomas have different frequencies of progression to malignancy. The genetic and epigenetic alterations of these tumors have not been studied in detail. In this study, we compared methylation status of p16, p14, VHL, and ppENK genes by methylation-specific PCR (MSP), and genetic alterations including K-ras and beta-catenin gene mutations, chromosome 3p loss, and microsatellite instability in 15 mucinous cystic neoplasms (10 benign and 5 borderline) and 16 serous microcystic adenomas. There were no significant differences between mucinous cystic neoplasms and serous microcystic adenomas in methylation of p16 (14%, 2/14 and 12%, 2/16), p14 (15%, 2/13 and 37%, 6/16), VHL (0/14 and 7%, 1/14), and ppENK (0/14 and 0/13), respectively. K-ras mutation was present only in mucinous cystic neoplasms but not in serous microcystic adenomas (33%, 5/15 versus 0/16; P =.004). In addition, LOH at 3p25, the chromosomal location of VHL gene, was present in 57% (8/14) of serous microcystic adenomas compared with in 17% (2/12) of mucinous cystic neoplasms (P =.03). No beta-catenin mutation, microsatellite instability, or mutation of transforming growth factor beta type II receptor was present in either type of tumors. In conclusion, K-ras mutations and allelic loss of VHL locus at 3p25, but not methylation, distinguished mucinous cystic neoplasms and serous microcystic adenomas. The differences in genetic alterations but not epigenetic alterations may explain the pathogenesis and progression to malignancy of these cystic tumors of pancreas.     

Serous neoplasms of the pancreas constitute a continuous spectrum of morphological patterns rather than distinct clinico-pathological variants. A study of 40 cases

Serous neoplasms (SN) of the pancreas account for 1-2% of all pancreatic tumours. Six morphological variants of SN were previously recognized: serous microcystic (cyst)adenoma, serous macrocystic (cyst)adenoma, von Hippel-Lindau-associated serous cystic neoplasm, solid serous adenoma/neoplasm, mixed serous-neuroendocrine neoplasm and serous cystadenocarcinoma. It was recently postulated that SN shows a continuous spectrum of morphological patterns rather than distinct clinico-pathological subtypes. To address this issue, we performed a detailed review of 40 SN cases diagnosed at our institution between 1989 and 2011. We found 11 cases of serous microcystic (cyst)adenoma, 5 cases of serous macrocystic (cyst)adenoma, and a single case of von Hippel-Lindau-associated serous cystic neoplasm. Apart from that, we found 20 cases of SN which showed features of both microcystic and macrocystic (cyst)adenomas, 2 cases of small 'incipient' SN and a single case of a mixed microcystic and solid adenoma. In conclusion, we showed that 'borderline' lesions among SNs truly exist and are not rare. The reason for such a wide diversity of morphological patterns of SN remains unknown.     

Serous oligocystic and ill-demarcated adenoma of the pancreas: a variant of serous cystic adenoma

Serous cystic tumours of the pancreas are uncommon and are usually classified as microcystic adenomas (MCA). As new types of serous cystic tumours of this organ have been reported we reviewed a series of 14 lesions and from macroscopic findings two groups were distinguished: ten tumours revealed the features of MCA, while four were clearly distinct from MCA. Grossly, the latter tumours showed only few cysts which were irregularly assembled in fibrous stroma. On the cut surface, there was neither a central stellate scar nor a circumscribed tumour border, features characterizing MCA. Microscopically, the cysts were lined by cuboidal, non-mucin-producing cells. Immunocytochemical staining for cytokeratins 7, 8, 18 and 19 revealed a ductal phenotype. All non-MCA were found in the head of the pancreas and three of them occurred in men. There were no tumour recurrences or signs of malignant transformation after resection (mean follow-up, 2.9 years). These results suggest that there are serous cystic tumours distinct from MCA which may represent another variant of the category of serous cystic adenomas of the pancreas. We propose the term serous oligocystic and ill-demarcated adenoma (SOIA) for these tumours. It is possible that the recently described macrocystic subtype of serous cystadenoma and SOIA are variants of the same tumour.     

Macrocystic serous cystadenoma of the pancreas: a morphologic variant differing from microcystic adenoma.

The term "microcystic adenoma" of the pancreas has gained nearly universal acceptance among pathologists owing to the characteristic gross and microscopic features of this tumor. The possible existence of macrocystic variants of serous cystadenoma has been largely ignored in the literature. We report five cases of macrocystic serous cystadenoma of the pancreas, two of which were of the unilocular type. These tumors exhibited distinctly different macroscopic features from microcystic adenoma, which created diagnostic difficulties for both the radiologist and pathologist. Computed tomography scans on all five cases were thought to represent either mucinous cystic neoplasms or pseudocysts and the tumors were misclassified in two of three cases on which intraoperative frozen sections were performed. In our opinion, microcystic and macrocystic serous tumors represent morphologic variants of the same benign pancreatic neoplasm and we suggest that the term "serous cystadenoma" be used to encompass all variants of this benign neoplasm.     

Multiple Neuroendocrine Tumors of the Pancreas in von Hippel-Lindau Disease Patients : Histopathological and Molecular Genetic Analysis

Although pancreatic neuroendocrine tumors (NETs) in von Hippel-Lindau (VHL) disease have been reported, their pathological features have not been characterized. In addition, it is unknown whether alterations of the VHL gene are responsible for pancreatic NET development. To evaluate NETs in VHL patients, we performed histopathological analysis of 30 pancreatic tumors in 14 patients. In addition, DNA from NETs and normal pancreatic tissue from 6 patients with documented germ-line VHL gene mutations was studied for allelic deletions of the second copy of the VHL gene by fluorescence in situ hybridization and polymerase chain reaction-based single-strand conformational polymorphism analysis. Morphologically, the tumors were characterized by solid, trabecular, and/or glandular architecture and prominent stromal collagen bands. Sixty percent of the tumors revealed at least focally clear-cell cytology. All tumors were positive for panendocrine immunohistochemistry markers (chromogranin A and/or synaptophysin); 35% of NETs demonstrated focal positivity for pancreatic polypeptide, somatostatin, insulin, and/or glucagon; and no immunostaining for pancreatic and gastrointestinal hormones was observed in 65% of tumors. Dense core neurosecretory granules were evident by electron microscopic examination, and the clear cells additionally revealed abundant intracytoplasmic lipid. All NETs that were subjected to genetic analysis showed allelic loss of the second copy of the VHL gene. We conclude that multiple, nonfunctional pancreatic NETs occur in VHL patients. Stromal collagen bands and clear-cell morphology are important histological features of VHL-associated NETs. The presence of allelic deletions of the VHL gene in pancreatic NETs provides direct molecular evidence for a role of the gene in their tumorigenesis and establishes NET as an independent tumor type of VHL disease.     

Pancreatic serous microcystic adenoma with extensive oncocytic change

Herein is reported a case of pancreatic serous microcystic adenoma with extensive oncocytic change in a 73-year-old woman. Histologically the tumor consisted of numerous small cysts, separated by thin or broad fibrous septa. These cysts were lined with uniform cells having abundant eosinophilic granular cytoplasm, which was negatively or weakly stained with PAS. Immunohistochemically, the cyst-lining cells were positive for cytokeratin (CK) 7, CK19, MUC1, MUC6, α-inhibin, and neuron-specific enolase (NSE), and negative for CK8, CK20, MUC2, and MUC5AC; these immunoprofiles coincide with those of serous microcystic adenoma. Immunostaining with anti-mitochondrial antibody showed dense granular positivity in the cytoplasm, which suggested an oncocytic phenotype. Thus, this case is considered a variant of serous microcystic adenoma characterized by extensive oncocytic change. To the authors' knowledge no similar case has been reported in the literature. It may pose problems in the differential diagnosis of the cystic pancreatic tumors with oncocytic change, but can be diagnosed on histology and immunohistochemistry.     

Allelic deletion and mutation of the von Hippel-Lindau (VHL) tumor suppressor gene in pancreatic microcystic adenomas.

An association between pancreatic microcystic (serous) adenomas (MCAs) and von Hippel-Lindau (VHL) disease has been suggested. However, genetic alterations of the VHL gene in MCAs of the pancreas have never been reported. In this study, we performed genetic analysis of 12 pancreatic MCAs. In 2 cases, VHL disease was documented clinically, and 10 cases were sporadic. For LOH analysis, tumor and normal pancreatic cells were procured from formalin-fixed, paraffin-embedded material using tissue microdissection. After DNA extraction, the samples were amplified by polymerase chain reaction using the polymorphic markers D3S2452, D3S1110, D3S192, and D3S656. In addition, the sporadic tumors were analyzed for VHL gene mutations using probes 3b/10b and K55/K56. Both MCAs associated with VHL disease showed LOH with at least one of the microsatellite markers tested. Among the 10 sporadic cases, 7 tumors showed LOH at the VHL gene locus. A somatic VHL gene mutation on exon 2 was documented in one sporadic case. The study provides the first direct genetic evidence for the role of the VHL gene in MCA tumorigenesis. Furthermore, VHL gene alterations may be detected in both VHL-associated and sporadic pancreatic MCAs.     

Molecular characterization of pancreatic serous microcystic adenomas: evidence for a tumor suppressor gene on chromosome 10q

Pancreatic serous microcystic adenomas (SCAs) are rare, benign tumors with a striking female preference. Virtually no information is available about chromosomal or genetic anomalies in this disease. We performed extensive molecular characterization of 21 cases of formalin-fixed, paraffin-embedded sporadic SCAs consisting in genome-wide allelic loss analysis with 79 microsatellite markers covering all 22 autosomes, assessment of microsatellite instability, and mutational analysis of the VHL, K-ras, and p53 genes in nine cases for which frozen tissue was available. Although no case showed microsatellite instability of the type seen in mismatch repair-deficient tumors, a relatively low fractional allelic loss of 0.08 was found. Losses on chromosome 10q were the most frequent event in SCAs (50% of cases), followed by allelic losses on chromosome 3p (40% of cases). Moderately frequent losses (>25% of cases) were found on chromosomes 1q, 2q, and 7q. The VHL gene, located on chromosome 3p, had somatic inactivating mutations in two of nine cases (22%), whereas no mutations were found in either K-ras or p53, in agreement with the finding that all 21 cases stained negative for p53 by immunohistochemistry. Our study indicates that the involvement of chromosomal arms 10q and 3p is characteristic of SCAs and that the VHL gene is involved in a subset of sporadic cases.     

Macrocystic serous cystadenocarcinoma of the pancreas: the first report of a new pattern of pancreatic carcinoma

Cystic pancreatic neoplasms are rare and include mucinous and microcystic cystadenoma (carcinomas) and the recently described macrocystic adenoma. Their accurate diagnosis is difficult by radiology, and histopathology remains the modality of choice. The case of a 42-year-old woman presenting with a gradually enlarging abdominal mass is reported. Imaging studies revealed a large unilocular cystic lesion in the pancreas. An exploratory laparotomy was done with excision of the cyst along with pancreas. Numerous microscopic sections revealed a serous neoplasm with atypical nuclear features and focal invasion of the cyst wall. A final pathological diagnosis of macrocystic serous cystadenocarcinoma of the pancreas was made. The patient has been doing well two years after surgery. This is the first case of a macrocystic serous cystadenocarcinoma of the pancreas, highlighting the need for extensive sampling of all cystic lesions of the pancreas in order to reach a correct diagnosis.     

Contrast-enhanced ultrasonograpic findings in pancreatic tumors

OBJECTIVE: The purpose of this article is to present the potentials and limits of contrast-enhanced ultrasonography (CEUS) in the characterization of pancreatic tumors, usually hypoechoic or cystic at B-mode ultrasound.CONCLUSION: As regards hypoechoic lesions at B-mode ultrasound, CEUS often can distinguish among adenocarcinoma, islet cell tumor and serous microcystic adenoma. As regards cystic lesions, CEUS in most cases doesn't add significative diagnostic information; therefore CT, MR or endoscopic US are almost always necessary for their proper characterization.     

Needle aspiration cytology of pancreatic cystic lesions

Forty-two histologically confirmed cases of pancreatic cystic lesions with cytologic evaluation by needle aspiration biopsy (NAB) were reviewed. There were 21 inflammatory pseudocysts (IPC), nine mucinous cystic neoplasms (MCN), six microcystic serous adenomas (MSA), one macrocystic serous adenoma, and five papillary solid and cystic neoplasms (PSCN). Correct cytodiagnosis was made in all cases of IPC and MCN. The contents of IPCs were characterized by turbid or blood-tinged fluid containing cellular debris, numerous foamy macrophages, and other inflammatory cells. There were few or no epithelial lining cells. The aspirates from MCNs showed gelatinous mucoid material containing mucus-secreting cells that were present singly, in clusters, or in sheets. Depending on the individual case, benign or malignant columnar cells, or an admixture of these cells, were present in a mucinous background. The preoperative needle aspirates of five MSAs were acellular. In one case of MSA and in one example of macrocystic serous adenoma, small monolayered sheets of benign cubic epithelial cells were seen in the needle aspirates. Similar cytologic findings were noted in the materials obtained by intraoperative NAB performed under direct vision of the aforementioned five MSAs. Difficulties were encountered in typing three PSCNs that yielded in NAB cells resembling those of an islet cell tumor. They were diagnosed as low-grade neoplasms (PSCN vs. islet cell tumor). In two other patients, a cytodiagnosis of PSCN was correctly made as the NAB revealed monomorphic tumor cells wrapping around small capillary blood vessels. Diagn. Cytopathol. 1997;17:177–182. © 1997 Wiley-Liss, Inc.     

中国人一个von Hippel-Lindau病的大家系调查及基因突变研究

目的 探讨中国人一个von Hippel-Lindau(VHL)病家系的临床特点及基因突变研究的临床意义。方法 调查一个von Hippel—Lindau病大家系，制定该家系发病的树状图；抽取27位家族成员外周血，采用聚合酶链反应和扩增产物直接测序进行基因检测；通过病史和影像学检查，获得该病的多脏器肿瘤发生情况。结果 该家族4代47人中18人患von Hippel-Lindau病，其中中枢神经系统成血管细胞瘤5例，肾癌合并中枢神经系统成血管细胞瘤3例，肾癌合并视网膜血管瘤3例，肾癌合并胰腺多发性囊肿1例，肾癌合并视网膜血管瘤及胰腺多发性囊肿2例，肾癌合并中枢神经系统成血管细胞瘤及胰腺多发性囊肿1例，肾脏多发性囊肿合并胰腺多发性囊肿1例和胰腺多发性囊肿2例。本组中，肾癌、中枢神经系统成血管细胞瘤、视网膜血管瘤和胰腺多发性囊肿的发生率分别为56％、50％、28％和39％。基因检测发现VHL基因第1外显子上第446位核苷酸A→G突变，该突变导致第78位编码氨基酸由天冬酰胺转变为丝氨酸。检测的27人中，15人呈现VHL基因突变，其中9例患病者、4例致病基因携带者及2例经影象学检查外科手术证实的无症状患者。其余12人无基因突变，同时无相应临床征象。结论 该家系属于von Hippel—Lindau病I型，肾癌发生率高而视网膜血管瘤发生率低是其主要的临床特点。基因检测在早期发现无症状患者和致病基因携带者及对该病家族成员进行临床监测方面起着重要作用，并在遗传生殖角度阻断该疾病的遗传有重要意义。     

Serous oligocystic adenoma of the pancreas: a clinicopathological and immunohistochemical study of three cases with ultrastructural findings

AIMS: Serous oligocystic adenoma of the pancreas is an uncommon benign neoplasm and is a recently described entity. To date, there are 19 adult cases of this tumour. We report three additional cases, two with macrocystic and one with unilocular types. We describe their clinicopathological, immunohistochemical and ultrastructural findings and review the world's literature. METHODS: For a 10-year period, we reviewed all benign cystic lesions of the pancreas with emphasis on serous oligocystic adenoma. We characterised serous oligocystic adenoma as an ill-demarcated or encapsulated mass, composed largely or exclusively of macrocysts (cysts measuring 20mm or more) but few in number (oligolocular). Grossly, it may contain only a single cyst (unilocular) of any size with a few satellite cysts observed on histological examination. Special stains and immunohistochemistry as well as electron microscopy were performed on three and two cases of serous oligocystic adenoma, respectively. RESULTS: Between 1990 and 2000, we collected 26 benign cystic lesions of the pancreas, three of which were serous oligocystic adenomas (two with macrocystic and one with unilocular types). Many of the cells lining the cysts showed PAS positivity. There was negative staining for PAS with diastase digestion, Alcian blue and mucicarmine. All cases showed positive staining for CAM5.2, AE1/AE3, EMA and CK7. The proliferation index marker was low. There was negative staining for CK20, insulin, glucagon, somatostatin, synaptophysin, chromogranin A, CEA and p53. Ultrastructural studies on two cases revealed similar findings. The single row of uniform epithelial cells lining the cysts was composed of simple cuboidal to flat cells which rested on a thin basal lamina. Their nuclei were round to ovoid. Glycogen granules were identified in the cytoplasm. Short microvilli emerged from the epithelial apical surface. Adjacent tumour cells were connected by microfilaments. CONCLUSIONS: Serous oligocystic adenomas of the pancreas are uncommon benign tumours. Prior to this study, 19 adults with these lesions were reported in the world's literature. No correct pre-operative diagnosis was carried out on all 22 cases. The 20 patients with follow-up ranging from 2 months to 5 years did not show tumour recurrence or malignant transformation.     

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.     

Cystic forms of typically solid pancreatic tumors

In addition to the well-known cystic lesions, the differential diagnosis of pancreatic cysts also includes cystic counterparts (or cystic change in) otherwise typically solid tumors of this organ. Pancreatic endocrine neoplasms (islet cell tumors) and ductal adenocarcinomas sometimes undergo cystic degeneration, the latter usually due to necrosis. Also, although acinar cell carcinoma is typically a solid tumor, its rare cystic counterpart, "acinar cell cystadenocarcinoma," has been reported. A rare variant of pancreatic ductal adenocarcinoma referred to as "large-duct-type" is characterized by microcystic ectasia of the invasive glands and may mimic other cystic tumors at the microscopic level. Secondary tumors, although exceedingly rare, may also potentially fall into the differential diagnosis of pancreatic cysts. Often, the morphological characteristics of these lesions are identical to those of their solid counterparts, and their diagnosis is not difficult if one is aware of their existence. This review focuses on these cystic counterparts of otherwise characteristically solid pancreatic neoplasms. Solid pseudopapillary tumor, in which cystic degeneration is so common that "cystic" has been a part of many alternate terms assigned to this neoplasm, is discussed in another article of this issue of Seminars in Diagnostic Pathology.     

Microcystic adenoma of pancreas: a case report

Microcystic adenomas of the pancreas are rare benign neoplasms that occur most frequently in elderly females. Characteristically, the tumors have a spongy gross appearance and are composed of innumerable cysts lined by flat, and cuboidal cells which are rich in glycogen. They commonly present with abdominal discomfort or pain. In this case report, we present a cystic neoplasm of pancreas in a 65-year-old lady who clinically presented with discomfort in the abdomen and hyperglycaemia. Proximal pancreatectomy was done. Histopathological examination of surgical specimen confirmed the diagnosis of "Microcystic Adenoma ofPancreas". Despite of the rarity, microcystic adenoma should kept in the mind as the differential diagnosis of cystic lesions of pancreas.     

Cystic neoplasms of the pancreas and tumor-like lesions with cystic features: a review of 418 cases and a classification proposal

Although cystic neoplasms and lesions of the pancreas are rare, they have attracted a great deal of attention because of their potential curability. Since, in recent years, several new entities have been identified, the relative frequency of the tumors and their classification need to be reevaluated. In a series of 1454 tumorous lesions of the pancreas collected between 1971 and 2003 in our surgical pathology files and consultation files, all cystic pancreatic neoplasms and tumor-like lesions were identified and typed both histologically and immunohistochemically. There were 418 cases (29%) showing cysts with a diameter ranging between 0.5 cm and 27 cm. Most common were solid pseudopapillary neoplasms (21%) and intraductal papillary-mucinous neoplasms (18%). When only the cystic neoplasms and lesions that had been resected in a single institution were considered, intraductal papillary mucinous neoplasms were the most frequent cystic neoplasms, while solid pseudopapillary neoplasms took fifth place behind ductal adenocarcinomas with cystic features, serous cystic neoplasms and mucinous cystic neoplasms. The most frequent cystic tumor-like lesions were pancreatitis-associated pseudocysts. New and rare entities that have recently been identified are mucinous nonneoplastic cysts, acinar cell cystadenomas and cystic hamartomas. Bearing in mind that figures from referral centers such as ours may be biased regarding the relative frequency of lesions, we concluded from our data that intraductal papillary-mucinous neoplasms are the most frequently occurring pancreatic cystic neoplasms, rather than solid pseudopapillary neoplasms. It was possible to classify all cystic lesions encountered in our files or described in the literature in a new system that distinguishes between neoplastic and nonneoplastic lesions, with further subdivisions into epithelial (adenomas, borderline neoplasms and carcinomas) and nonepithelial tumors. This classification is easy to handle and enables a distinction on the basis of clinical behavior and prognosis.