Epithelioid angiomyolipoma: a pathological entity discovered in Verona with the endorsement of Doctor Rosai

In this manuscript, we summarize the main features of angiomyolipoma highlighting the recognition of epithelioid angiomyolipoma and the discovery of immunohistochemical expression of HMB45 in a group of tumors that now are referred to as as PEComas. In this scenario, Dr. Rosai believed in our intuition, demonstrating his intellectual honesty and motivated us with his experience (“when a tumor seems malignant it is malignant”) and enthusiasm for the new entities (“in Verona, you use HMB45 instead of H&E”). He really pushed the improvement of the knowledge in this field.

Investigating the CVD Synthesis of Graphene on Ge(100): toward Layer-by-Layer Growth

Germanium is emerging as the substrate of choice for the growth of graphene in CMOS-compatible processes. For future application in next generation devices the accurate control over the properties of high-quality graphene synthesized on Ge surfaces, such as number of layers and domain size, is of paramount importance. Here we investigate the role of the process gas flows on the CVD growth of graphene on Ge(100). The quality and morphology of the deposited material is assessed by using μ-Raman spectroscopy, X-ray photoemission spectroscopy, scanning electron microscopy, and atomic force microscopy. We find that by simply varying the carbon precursor flow different growth regimes yielding to graphene nanoribbons, graphene monolayer, and graphene multilayer are established. We identify the growth conditions yielding to a layer-by-layer growth regime and report on the achievement of homogeneous monolayer graphene with an average intensity ratio of 2D and G bands in the Raman map larger than 3.

Nanowire-based field effect transistors for terahertz detection and imaging systems

The development of self-assembled nanostructure technologies has recently opened the way towards a wide class of semiconductor integrated devices, with progressively optimized performances and the potential for a widespread range of electronic and photonic applications. Here we report on the development of field effect transistors (FETs) based on semiconductor nanowires (NWs) as highly-sensitive room-temperature plasma-wave broadband terahertz (THz) detectors. The electromagnetic radiation at 0.3 THz is funneled onto a broadband bow-tie antenna, whose lobes are connected to the source and gate FET electrodes. The oscillating electric field experienced by the channel electrons, combined with the charge density modulation by the gate electrode, results in a source-drain signal rectification, which can be read as a DC signal output. We investigated the influence of Se-doping concentration of InAs NWs on the detection performances, reaching responsivity values higher than 100 V W⁻¹, with noise-equivalent-power of ∼10⁻⁹ W Hz(⁻½). Transmission imaging experiments at 0.3 THz show the good reliability and sensitivity of the devices in a real practical application.

Healing of fresh extraction sockets filled with bioactive glass particles: histological findings in humans

PURPOSE

The aim of the present study was to histologically evaluate fresh human sockets filled with bioactive glass after 6 months of healing.

MATERIALS AND METHODS

In 13 patients, 32 single extraction sites in the anterior area underwent socket ridge preservation procedure (RPP) with a bioactive glass (BioRestore™, Inion Oy, Tampere, Finland). At implant installation, 22 bone cores were trephined out and processed for histomorphometric and immunohistochemical analysis.

RESULTS

Newly formed immature bone around residual particles of bioactive glass was found in all 22 biopsies. The histomorphometry of the amount of bone, provisional matrix, and residual graft returned a mean ± SD value of 54 ± 31%, 37.9 ± 25.6%, and 8.1 ± 7.8, respectively, 6 months after RPP.

CONCLUSION

The use of this grafting material in fresh extraction sockets appears to delay the healing processes of the alveolar bone; therefore, its indication as a material for RPP when implant placement is considered within 6 months after extraction should be revised.

Molecular pathology of lymphangioleiomyomatosis and other perivascular epithelioid cell tumors

CONTEXT

Lymphangioleiomyomatosis (LAM) is a cystic lung disease that can be included in the wide group of proliferative lesions named PEComas (perivascular epithelioid cell tumors). These proliferative tumors are characterized by the coexpression of myogenic and melanogenesis-related markers. In all these lesions, genetic alterations related to the tuberous sclerosis complex (TSC) have been demonstrated. Striking improvements in the understanding of the genetic basis of this autosomal dominant genetic disease are coupled to the understanding of the mechanisms that link the loss of TSC1 (9q34) or TSC2 (16p13.3) genes with the regulation of the Rheb/m-TOR/p70S6K pathway. These data have opened a new era in the comprehension of the pathogenesis of LAM and have also suggested new therapeutic strategies for this potentially lethal disease.

OBJECTIVE

To present and discuss the pathologic and molecular features of LAM within the spectrum of PEComas, providing a rational approach to their diagnosis.

DATA SOURCES

The published literature and personal experience.

CONCLUSIONS

The inclusion of LAM within the PEComa category is supported by a variety of biologic data and can significantly help in providing a comprehensive view of this interesting and clinically relevant group of lesions. The demonstration of molecular alterations of the mTOR pathway in LAM and other PEComas represents a rational basis for innovative therapeutic approaches with inhibitors of mTOR signaling.

Cathepsin-k expression in pulmonary lymphangioleiomyomatosis

Lymphangioleiomyomatosis is a rare and progressive lung cystic disease, caused by the infiltration of lung parenchyma by mesenchymal cells characterized by co-expression of contractile proteins and melanocytic markers. The pathogenesis of lymphangioleiomyomatosis is determined by mutations affecting tuberous sclerosis complex (TSC) genes, with eventual deregulation of the Rheb/mTOR/p70S6K pathway, and the potential therapeutic activity of mTOR inhibitors is currently under investigation. To better understand the molecular mechanisms involved in the pathogenesis of lymphangioleiomyomatosis, we investigated the expression of cathepsin-k (a papain-like cysteine protease with high matrix-degrading activity). The rationale of this choice was based on the recent demonstration that mTOR inhibitors can regulate major functional activities of osteoclasts, including the expression of cathepsin-k. The immunohistochemical study included 12 cases of lymphangioleiomyomatosis. Twelve angiomyolipomas and several lung diseases (sarcoidosis, organizing pneumonia, usual interstitial pneumonia, emphysema) were investigated as controls. In all lymphangioleiomyomatosis cases, strong cathepsin-k immunoreactivity was demonstrated, restricted to lymphangioleiomyomatosis cells. Similar expression levels were observed in renal angiomyolipomas. These observations extend the knowledge regarding the immunophenotypic profile of lymphangioleiomyomatosis cells, and provide a useful new marker for diagnosis in difficult cases (eg, in small transbronchial biopsies). The strong expression of such a potent papain-like cysteine protease in lymphangioleiomyomatosis cells can significantly contribute to the progressive remodelling of lung parenchyma observed in this deadly disease, with eventual formation of lung cysts. It is possible to speculate that mTOR inhibitors may exert part of their action by limiting the destructive remodelling of lung structure.

PEComas: the past, the present and the future

The perivascular epithelioid cell (PEC) is a cell type constantly present in a group of tumors called PEComas. PEC expresses myogenic and melanocytic markers, such as HMB45 and actin. Recently, recurrent chromosomal alterations have been demonstrated in PEC. At present, PEComa is a widely accepted entity. In the past 10 years, the use of this term has allowed to report and describe numerous cases permitting to start highlighting the biology of this group of lesions. PEComas are related to the genetic alterations of tuberous sclerosis complex (TSC), an autosomal dominant genetic disease due to losses of TSC1 (9q34) or TSC2 (16p13.3) genes which seem to have a role in the regulation of the Rheb/mTOR/p70S6K pathway. There are some open questions about PEComas regarding its histogenesis, the definition of epithelioid angiomyolipoma and the identification of the histological criteria of malignancy. An innovative therapeutic trial using rapamycin is under way for tumors occurring in TSC such as renal angiomyolipoma and lymphangioleiomyomatosis. Its success could provide the rationale for the use of the same drug in other lesions composed of PECs, especially in the malignant ones.

Diagnostic utility of S100A1 expression in renal cell neoplasms: an immunohistochemical and quantitative RT-PCR study

S100A1 is a calcium-binding protein, which has been recently found in renal cell neoplasms. We evaluated the diagnostic utility of immunohistochemical detection of S100A1 in 164 renal cell neoplasms. Forty-one clear cell, 32 papillary, and 51 chromophobe renal cell carcinomas, and 40 oncocytomas, 164 samples of normal renal parenchyma adjacent to the tumors and 13 fetal kidneys were analyzed. The levels of S100A1 mRNA detected by quantitative RT-PCR analysis of frozen tissues from seven clear cell, five papillary, and six chromophobe renal cell carcinomas, four oncocytomas, and nine samples of normal renal tissues adjacent to neoplasms were compared with the immunohistochemical detection of protein expression. Clear cell and papillary renal cell carcinomas showed positive reactions for S100A1 in 30 out of 41 tumors (73%) and in 30 out of 32 (94%) tumors, respectively. Thirty-seven renal oncocytomas out of 40 (93%) were positive for S100A1, whereas 48 of 51 (94%) chromophobe renal cell carcinomas were negative. S100A1 protein was detected in all samples of unaffected and fetal kidneys. S100A1 mRNA was detected by RT-PCR in all normal kidneys and renal cell neoplasms, although at very different levels. Statistical analyses comparing the different expression of S100A1 in clear cell and chromophobe renal cell carcinomas observed by immunohistochemical and RT-PCR methods showed significant values (P<0.001), such as when comparing by both techniques the different levels of S100A1 expression in chromophobe renal cell carcinomas and oncocytomas (P<0.001). Our study shows that S100A1 protein is expressed in oncocytomas, clear cell and papillary renal cell carcinomas but not in chromophobe renal cell carcinomas. Its immunodetection is potentially useful for the differential diagnosis between chromophobe renal cell carcinoma and oncocytoma. Further, S100A1 protein expression is constantly detected in the normal parenchyma of the adult and fetal kidney.

Chromosomal gains in the sarcomatoid transformation of chromophobe renal cell carcinoma

The hallmark of chromophobe renal cell carcinoma is multiple chromosomal losses from among chromosomes 1, 2, 6, 10 and 17. Chromophobe renal cell carcinoma with distant metastases or sarcomatoid transformation are uncommon and little is known about their chromosomal abnormalities. We collected six sarcomatoid chromophobe renal cell carcinomas and three primary chromophobe renal cell carcinomas with distant metastases. A cytogenetic analysis by fluorescent in situ hybridization on paraffin-embedded tissue was performed using centromeric probes for chromosomes 1, 2, 6, 10 and 17. We found more than one signal in four of six (66%) sarcomatoid chromophobe renal cell carcinomas, in both sarcomatoid and adjacent epithelial components. Both primary chromophobe renal cell carcinomas and matched metastases showed single signals for all chromosomes studied in two cases and no abnormalities in the remaining case. We concluded that: (1) both epithelial and sarcomatoid components of sarcomatoid chromophobe renal cell carcinoma show different genetic abnormalities from those characteristic of chromophobe renal cell carcinoma; (2) sarcomatoid chromophobe renal cell carcinomas frequently have multiple gains (polysomy) of chromosomes 1, 2, 6, 10 and 17; (3) distant metastases show the same genetic patterns, usually chromosomal losses (monosomy), found in the primary tumors.

Role of molecular markers in diagnosis and prognosis of renal cell carcinoma

It has been demonstrated that different renal cell neoplasms have characteristic morphologic and genetic features. Histologic subtyping of renal epithelial neoplasms has been shown to be of prognostic value; therefore they must be correctly classified. Although adequate sampling and a good understanding of the morphologic features usually minimize diagnostic errors, the use of immunohistochemical and chromosomal analysis on formalin-fixed, paraffin-embedded tissues can be necessary. These techniques can facilitate diagnosis on small biopsies, which are increasingly obtained from renal masses. An immunohistochemical panel including CD10, parvalbumin, AMACR, CK7 and S100A1 seems the most promising; fluorescence in situ hybridization analysis using centromeric probes to evaluate the gains and losses of the chromosomes can be helpful in selected cases. A wide variety of molecular markers have been examined, but further research is required to prove their value as prognostic tools.

Perivascular epithelioid cell tumor (PEComa) in the genitourinary tract

Perivascular epithelioid cell tumors (PEComas) are mesenchymal tumors composed of histologically, immunohistochemically, ultrastructurally, and genetically distinctive cells. PEComas have been described in different organs and are considered ubiquitous tumors. In this review we discuss recent informations related to PEComas in the genitourinary tract.

Needle Core Length is a Quality Indicator of Systematic Transperineal Prostate Biopsy

OBJECTIVE

To analyse the length of needle cores sampled as a quality indicator in systematic transperineal prostate biopsy. We assessed the correlation of core length with the other clinical and topographic parameters.

MATERIAL AND METHODS

We prospectively evaluated data from 509 consecutive patients who underwent a first set of transrectal ultrasound-guided transperineal prostate biopsy for suspected prostate cancer. Fourteen cores were sampled from each patient. Needle cores were stretched and placed in tissue cassettes between two nylon meshes according to the pre-embedding methods of prostate needle biopsy specimens. For single biopsy core, the measurement of length (in millimetres) and any percentage of cancer in the biopsy specimen were reported.

RESULTS

The mean length of 7,126 analysed cores was 14.14+/-4.35mm. All cores were longer than 10mm. The mean length of needle cores sampled did not correlate with patient age, total prostate-specific antigen value, digital rectal examination, and prostate volume. The whole mean length of the six samples from the peripheral zone of the right lobe was higher than the mean corresponding value of the six samples from the left lobe peripheral zone (p<0.001). The transperineal approach allows a greater sampling of the prostate apex than of the midgland and prostate base (p<0.001).

CONCLUSIONS

The length of the needle cores sampled during transperineal prostate biopsy fulfils the parameters of quality required by pathologists for an appropriate evaluation of the biopsy specimen.

External validation of the Mayo Clinic Stage, Size, Grade and Necrosis (SSIGN) score to predict cancer specific survival using a European series of conventional renal cell carcinoma

PURPOSE

We validated the Mayo Clinic SSIGN score in an independent European sample of patients who were surgically treated for conventional RCC.

MATERIALS AND METHODS

In our kidney cancer database we identified 388 patients who were treated with radical or partial nephrectomy for conventional RCC between 1986 and 2000. Associations of the pathological features studied with death from RCC were evaluated using the log rank test and Cox proportional hazards regression model. The predictive ability of competing models was evaluated using the c index.

RESULTS

Median followup in the 290 patients who were alive at last followup was 5 years (range 5 months to 17 years). The estimated cancer specific survival rate 5 years following surgery was 81.3%. All features that comprise the SSIGN score except tumor size were significantly associated with death from RCC in a multivariate setting, resulting in a c index of 0.90. The median SSIGN score in the 388 patients studied was 3 (range 0 to 15). The c index in a model containing the clear cell SSIGN score was 0.88. Five-year cancer specific survival rates in patients with a score of 0 to 2, 3 to 4, 5 to 6, 7 to 9 and 10 or more were 100.0%, 90.5%, 63.6%, 46.8% and 0%, respectively.

CONCLUSIONS

We provide the first external validation of the Mayo Clinic SSIGN score for conventional RCC. This simple algorithm resulted in a high degree of prognostic accuracy.

Prognostic role of the histologic subtypes of renal cell carcinoma after slide revision

OBJECTIVES

To evaluate concordance, using the kappa statistic, between tumour histotypes assigned at initial diagnosis and those after slide revision, and to assess the independent predictive value of reviewed tumour histotype.

MATERIALS AND METHODS

We analysed records of 491 patients who had undergone partial or radical nephrectomy for renal cell carcinoma (RCC) in our department from 1986 to 2000. Pathologic slides were reviewed by one uropathologist blinded to original diagnoses and follow-up data, who reassigned histologic subtype and nuclear grades.

RESULTS

Concordance between original and reviewed histotypes was substantial (kappa = 0.52). Data were affected by the year of initial diagnosis: Concordance was moderate (kappa = 0.43) in patients treated from 1986 to 1997 and substantial (kappa = 0.73) in those observed thereafter. The original histotype did not stratify the cancer-related outcome. According to the reviewed histotypes, the 5-year cancer-specific survival probabilities of conventional, papillary and chromophobe RCC patients were 81.3%, 90.1% and 100%, respectively (p = 0.009). Patients with conventional RCC showed significantly lower cancer-specific survival than those with papillary or chromophobe RCC, even in the cases with locally advanced (p = 0.04) or high-grade (p = 0.02) neoplasms. The reviewed histologic subtype was not an independent prediction of cancer-specific survival on multivariate analysis.

CONCLUSION

Concordance between histologic subtype assigned before 1997 and after slide revision was only moderate. In univariate analysis, reviewed tumour histotype stratified cancer-related outcome, but the data of multivariate analysis were strongly influenced by the prevalent number of conventional RCC.

The Potential Impact of Prostate Volume in the Planning of Optimal Number of Cores in the Systematic Transperineal Prostate Biopsy

OBJECTIVES

We compared the detection rates of different transperineal prostate biopsy protocols with the aim to optimize the number of cores to sample according to prostate volume.

MATERIAL AND METHODS

From October 2002 to October 2004 we evaluated 480 consecutive patients with PSA between 2.5 and 20 ng/ml undergoing the first set of prostate biopsy. All patients underwent a 14-core TRUS-guided transperineal prostate biopsy, including 12 cores in the peripheral and two in the transitional zone. The detection rate of the 14-core scheme was compared to the one of the other biopsy schemes obtained through the exclusion of pairs of cores. Data were stratified according to the different TRUS estimated prostate volumes.

RESULTS

The detection rate of the standard sextant was 35.2%, while those of the 8-core schemes ranged from 37.1 to 38.8%. The 10-core schemes yielded detection rates of 39.6-40.8% and the protocol with 12 biopsies in the peripheral zone diagnosed prostate cancer in 42.1% of the patients. In patients with <30 cc prostate volume, the detection rate of the 14-core scheme was 43.8% and resulted statistically overlapping to the 8-peripheral cores protocol. In patients with 30.1-50 cc prostate volume a 12-peripheral core biopsy reproduced the results of the 14-core sampling. In prostates larger than 50 cc, an even more extensive procedure was mandatory, considering the low detection rate of the 14-core scheme (24.2%).

CONCLUSION

Transperineal prostate biopsy is a safe procedure with a very low complication rate and high cancer detection rate. Prostate volume is the most relevant variable in the planning of the optimal number of cores in the extensive first biopsy set. A protocol with more than 8 peripheral cores) is recommended only in patients with prostate volume larger than 30 cc.

CD10 is expressed in a subset of chromophobe renal cell carcinomas

CD10 has been considered a useful marker in the diagnosis of renal carcinomas, because of its expression in clear cell and papillary renal cell carcinomas and its absence in chromophobe renal cell carcinomas. On the other hand, chromophobe renal cell carcinoma expresses parvalbumin, which is absent in clear cell and papillary renal cell carcinomas. To further address the relevance of these markers, we studied the expression of CD10 and parvalbumin in 42 samples of chromophobe renal cell carcinoma (seven of which had aggressive features, including invasion beyond the renal capsule, renal vein invasion, metastases, or sarcomatoid transformation), 75 clear cell renal cell carcinomas (eight metastatic) and 51 papillary renal cell carcinomas (two metastatic). CD10 was found in 100% of clear cell renal cell carcinomas, 63% of papillary renal cell carcinomas and in all metastatic cases of both types. At variance with previous studies, we found CD10 expression in from 30 to 90% of the neoplastic cells, in 11 of 42 (26%) chromophobe renal cell carcinomas. The CD10-positive cases included five of the seven (71%) chromophobe renal cell carcinoma with aggressive features. Statistical analysis showed significant association of CD10-positive tumors with clinicopathologic aggressiveness (P=0.003) and mitotic figures (P=0.04). Parvalbumin was strongly expressed in all primary and metastatic chromophobe renal cell carcinomas. Western blot analysis was utilized to confirm the expression of both CD10 and parvalbumin in chromophobe renal cell carcinomas.

Cushing's syndrome induced by bronchopulmonary carcinoid tumours: a review of 98 cases and our experience of two cases

Bronchopulmonary carcinoids are one of the most common cause of ectopic secretion of corticotropin (ACTH) and account for approximately 1% of all the patients in whom Cushing's syndrome develops. We reviewed 98 cases described in the World Literature and we report on two new cases. A 60-year old woman affected by Cushing's syndrome underwent to surgical wedge resection of a peripheral pulmonary nodule and a 30-year old woman with similar clinical features underwent to middle lobectomy for a small hilar neoplasm. Histopathologic examination of the tumours defined them as typical bronchopulmonary carcinoids. The patients are asymptomatic and with no sign of recurrence 72 and 30 months after surgery. According to our review we found no clear evidence that bronchial carcinoids associated with Cushing's syndrome should be considered a more aggressive variant or subtype of the typical carcinoid. If Cushing's syndrome does not disappear after surgery, the presence of residual disease (often a nodal involvement) should be investigated. A long-term relapse of the syndrome requires a careful search for local or distant neoplastic recurrence.

Original and reviewed nuclear grading according to the Fuhrman system

BACKGROUND

The objective of the current study was to evaluate the reproducibility of the Fuhrman nuclear grading system as well as its independent predictive value in a series of patients with conventional renal cell carcinoma (RCC).

METHODS

The authors selected 388 patients who had undergone surgical treatment for conventional RCC between 1986 and 2000. Pathology slides from the selected patients were reviewed by a single pathologist, who reassigned a Fuhrman nuclear grade and assessed the presence of tumor necrosis. The pathologist was blinded to both the original pathologic diagnosis and follow-up data. The kappa statistic was used to evaluate concordance between original and reviewed nuclear grades. The log-rank test was used for univariate analyses, and a Cox proportional hazards model was used for multivariate analyses.

RESULTS

The original Fuhrman nuclear grade was Grade 1 (G1) in 111 patients (28.6%), G2 in 141 patients (36.3%), G3 in 108 patients (27.8%), and G4 in 28 patients (7.3%). After pathology slide review, nuclear grades were reassigned as follows: G1 in 49 patients (12.6%), G2 in 138 patients (35.6%), G3 in 150 patients (38.7%), and G4 in 51 patients (13.1%). The grade of concordance was moderate (kappa=0.44; P <0.001). Univariate analyses identified three separate prognostic categories defined by nuclear grade (G1 and G2 vs. G3 vs. G4). Both the original and the reviewed Fuhrman nuclear grading systems were capable of independently predicting disease-specific survival in patients with conventional RCC.

CONCLUSIONS

The interobserver reproducibility of Fuhrman nuclear grading was moderate. The substantial overlap in survival curves for G1 and G2 tumors provided an opportunity to cluster those categories, and the resulting three-tiered nuclear grading system was an independent predictor of cause-specific survival in patients with conventional RCC. Other independent predictors of survival included pathologic stage and tumor necrosis status.

Collagen I and III mRNA gene expression and cell growth potential of skin fibroblasts in patients with essential hypertension

OBJECTIVES

Despite the claimed disregulation of extracellular matrix synthesis and the increased proliferation rate of different cell types in experimental models of hypertension, very few data are available on collagen synthesis and the proliferation rate of fibroblasts in essential hypertensive patients.

DESIGN

We measured collagen I, collagen III, histone H3 mRNA gene expression, collagen protein concentration and thymidine incorporation in fibroblasts from 17 essential hypertensive patients (EH) and 13 healthy normotensive control subjects (NC).

METHODS

A Northern blot analysis was performed on fibroblasts in culture obtained from skin biopsies. Collagen protein concentration and DNA synthesis were measured by means of incorporation of tritiated proline and tritiated thymidine, respectively.

RESULTS

In cultivated fibroblasts from hypertensives, the expression of collagen III mRNA after addition of fetal calf serum was significantly increased in comparison with that of normotensive-derived cells. After addition of fetal calf serum, collagen protein was statistically increased in cultures from EH patients as compared to NC. In hypertensives, the expression of histone H3 mRNA as well as tritiated thymidine incorporation were both increased as compared to normotensives.

CONCLUSIONS

Our data suggest that cultivated fibroblasts from essential hypertensive patients are characterized by an increased expression of type III collagen mRNA and collagen protein synthesis in response to fetal serum, as compared to normotensive-derived cells. Cells from hypertensives are characterized by an increased rate of proliferation after addition of fetal serum, as ascertained by increased thymidine incorporation and increased histone H3 mRNA gene expression, as compared to normotensive-derived cells. This phenotype could be genetically determined and may have an important role in the pathogenesis of essential hypertension.

Oncocytoma-like angiomyolipoma. A clinicopathologic and immunohistochemical study of 2 cases

We report the clinical, pathologic, and immunohistochemical features of an unusual tumor of the kidney composed of densely eosinophilic, polygonal epithelioid cells. The patients were a 56-year-old woman and a 35-year-old man. The renal tumors were discovered during follow-up for breast carcinoma and evaluation for abdominal pain, respectively. The tumors closely resembled oncocytoma in routine sections, but were negative for epithelial markers and positive for HMB-45, a pattern of reactions characteristic of angiomyolipoma. In the woman, a single additional microscopic angiomyolipoma was present in the renal parenchyma at a distance from the main tumor. Both patients are alive without recurrence 7 and 10 years after surgery, respectively. Based on clinical, morphologic, and immunophenotypic features, we conclude that these tumors are oncocytoma-like angiomyolipomas.

Renal disease in adults with TSC2/PKD1 contiguous gene syndrome

The most common renal lesions of tuberous sclerosis complex, an autosomal-dominant syndrome resulting from losses of TSC1 (9q34) or TSC2 (16p13.3), are renal cysts and angiomyolipomas. Epithelial neoplasms are less common. The TSC2 gene lies adjacent to PKD1, the major gene responsible for autosomal-dominant polycystic kidney disease. Recently, a deletion mutation disrupting both TSC2 and PKD1 has been described in young children with tuberous sclerosis complex with severe renal cystic disease. This disease has been termed the TSC2/PKD1 contiguous gene syndrome. We describe the lesions in the resected kidneys of two adults with TSC2/PDK1 contiguous gene syndrome, at the time of the nephrectomies: a 31-year-old man and his 44-year-old mother. The four kidneys were enlarged reniform masses composed of cysts lined by flattened, cuboidal, or, infrequently, large deeply eosinophilic epithelial cells. The kidneys also contained numerous classic angiomyolipomas and rare intraglomerular microlesions. In the son the largest tumor was a monotypic epithelioid angiomyolipoma. In the wall of his left renal pelvis there was a plaque-shaped, HMB-45-positive localized lesion of lymphangioleiomyomatosis. This is the first description of the renal lesions in adults with genetically confirmed TSC2/PDK1 contiguous gene syndrome. The pathologic findings highlight the importance of thorough sampling for histology in polycystic kidney diseases and indicate that the observation of an angiomyolipoma in biopsy material from patients with enlarged cystic kidneys should suggest the diagnosis of TSC2/PKD1 contiguous gene syndrome, even in cases without ultrasonographic and macroscopic evidence of angiomyolipoma.

Parvalbumin is constantly expressed in chromophobe renal carcinoma

Chromophobe renal carcinoma is composed of neoplastic cell showing several features similar to those found in the intercalated cells of the collecting ducts. Because the distal nephron expresses calcium-binding proteins playing a role in calcium homeostasis, we reasoned that these proteins could be expressed by chromophobe carcinoma and therefore represent a diagnostic marker. We studied the immunohistochemical expression of different calcium-binding proteins (parvalbumin, calbindin-D28K, and calretinin) in 140 renal tumors, including 75 conventional (clear cell) carcinomas, 32 chromophobe carcinomas, 17 papillary renal cell carcinomas, and 16 oncocytomas. Parvalbumin was strongly positive in all primary chromophobe carcinomas and in one pancreatic metastasis; it was positive in 11 of 16 oncocytomas and absent in conventional (clear cell) and papillary renal cell carcinomas, either primary or metastatic. Calbindin-D28K and calretinin were negative in all tumors, with the exception of two chromophobe carcinomas, four oncocytomas, and two papillary renal cell carcinomas showing inconspicuous calretinin expression. Our data demonstrate that parvalbumin may be a suitable marker for distinguishing primary and metastatic chromophobe carcinoma from conventional (clear cell) and papillary renal cell carcinoma. Moreover, they suggest a relationship between chromophobe renal carcinoma and renal oncocytoma and indicate that chromophobe carcinoma exhibits differentiation toward the collecting-duct phenotype.

Renal angiomyolipoma with epithelioid sarcomatous transformation and metastases: demonstration of the same genetic defects in the primary and metastatic lesions

Angiomyolipoma (AML) is a benign neoplasm that occurs either sporadically or in patients with tuberous sclerosis complex (TSC) and shows frequent allelic losses at chromosome arm 16p. It has been suggested recently that the melanogenesis marker-positive perivascular epithelioid cell (PEC) has been found consistently in AML. The authors report a 50-year-old woman without evidence of TSC affected by classic renal AML containing an area composed of atypical epithelioid cells with the same morphoimmunophenotypic characters of PEC. After 7 years from surgical removal of the lesion, the patient developed a local recurrence and successive lung and abdominal metastases that showed morphologic and immunohistochemical features overlapping those of the epithelioid area of the previously removed AML. Genetic analysis showed that the classic AML and its epithelioid area as well as the pulmonary and abdominal metastases shared the same allelic loss on chromosome arm 16p. Based on these findings, the authors view this case as evidence of a malignant transformation of a classic AML with morphologic, immunophenotypic, and genetic demonstration of its clonal origin.

Multiple radiculopathy of the lower limbs in a cancer patient with meningeal carcinomatosis

Meningeal carcinomatosis occurs in 1%-5% of patients with breast cancer. Early diagnosis and aggressive treatment of neurologic involvement are important factors of prognosis. We report a case of a 52-year-old woman who was affected by bilateral breast carcinoma treated with surgery and chemotherapy. Six years after she had become asymptomatic, X-rays showed lumbar spine metastases which were treated with radiotherapy. After 1 year she began to suffer from lower limb paresthesias, unsteadiness and unstable gait. Clinical examination showed lower limb sensory ataxia with lack of knee and ankle reflexes, and hypopallesthesia from the iliac spine to the foot. Spinal magnetic resonance imaging (MRI) with contrast agent revealed no medullar compression. Electromyography disclosed bilateral involvement of L4-L5-S1 roots and corresponding paraspinal muscles. Sensory and motor conductions were normal. Cerebrospinal fluid (CSF) examination showed the presence of neoplastic cells, confirming the diagnosis of meningeal carcinomatosis. Our patient underwent 9 cycles of intrathecal methotrexate therapy (25 mg/cycle) with improvement of ataxia and relief of paresthesias. One year later, CSF examination is still negative. We point out the importance of electrodiagnostic studies and CSF examination in the early documentation of root involvement in cancer patients, when computed tomography, MRI and myelography are normal. Early diagnosis may lead to effective therapy which prolongs survival.

[A rare case of acute scrotum. Thrombophlebitis from ectasia of the left pampiniforme plexus]

The acutely painful scrotum may be due to testicular torsion, twisted testicular appendages, twisted spermatic cord or epididymitis. Most rarely it occurs as a result of a testicular trauma, orchitis, idiopathic scrotal edema, idiopathic infarction of testis and vaginalis tunica or testicular neoplasm; a spontaneous thrombosis of the spermatic vein vessels is quite unusual. A rare case of thrombosis of a dilated pampiniform plexus which occurred in a 6 year-old child is reported and its clinical presentation, diagnosis and treatment is discussed. The difficulty in making such a diagnosis is stressed since thrombosis of the spermatic vein is quite a rare entity; a conservative approach is suggested as a treatment of choice whenever a definite diagnosis is made, otherwise surgical intervention (ligation of the spermatic vein, if necessary) is required in order to rule out any other urologic emergency.

Congenital cystic mesoblastic nephroma

Congenital mesoblastic nephroma is a relatively rare infantile renal tumor. It comprises 3-6% of renal masses in childhood and 50% during the neonatal period. Most mesoblastic nephroma occur in the newborn period, with 80% of the cases being reported within the first month of life. Macroscopically the tumor is composed of a solid mass of different sizes tending to invade the surrounding structures and renal parenchyma. The authors report a case of cystic mesoblastic nephroma of the cellular subtype, with diffuse areas of hemorrhage and necrosis. The tumor was treated by surgical excision with radical nephrectomy and the child is doing well 4 years after the operation.

Carcinomalike monotypic epithelioid angiomyolipoma in patients without evidence of tuberous sclerosis: a clinicopathologic and genetic study

We report the clinicopathologic, immunohistochemical, ultrastructural, and genetic features of an unusual renal tumor composed of large, atypical, densely packed, clear/eosinophilic epithelioid cells. Three patients, two men and one woman (ages 31, 36, and 60 years of age, respectively), had abdominal pain. Morphologically, all cases showed aggressive features (largeness, atypical cells, sarcomatoid features, necrosis, and, in one case, invasion of the renal vein). Despite the marked morphologic resemblance of these tumors to high-grade sarcomatoid renal cell carcinoma, their phenotype (HMB45+, CD68+/-, actin+/-, and vimentin and keratin negative) is in contrast to that observed in epithelial tumors and parallels the phenotypic profile of angiomyolipoma. Ultrastructural analysis showed the presence of glycogen, mitochondria, and prominent electron-dense, membrane-bound granules in the neoplastic cells, and the absence of melanosomes or premelanosomes. Genetic study, performed using polymerase chain reaction from paraffin sections, showed a loss of heterozygosity at the TSC2-containing region on 16p in one case, and on 3p in two cases, showing that multiple genetic alterations are taking place in these tumors. Follow-up has shown local recurrence in one case after 6 years, and the patient died 1 year later of cardiorespiratory failure. The other two patients are well after 26 and 10 months. All three patients were evaluated for signs of tuberous sclerosis, and findings were negative. We suggest that these tumors should be considered close relatives of the angiomyolipoma variants, composed purely of perivascular epithelioid cells. More cases and longer follow-up durations are needed to fully evaluate its prognostic implication.

Apparent renal cell carcinomas in tuberous sclerosis are heterogeneous: the identification of malignant epithelioid angiomyolipoma

Renal epithelial tumors (carcinoma and oncocytoma) have been reported with higher a frequency than expected in patients with the tuberous sclerosis complex. However, the recent identification of a monotypic, epithelioid variant of angiomyolipoma, closely simulating renal cell carcinoma, has cast doubt on the real frequency of carcinoma. Immunohistochemical analysis with a panel of antibodies, including melanogenesis marker HMB45, can discriminate between carcinoma and carcinoma-like angiomyolipoma. We studied five tumors previously reported as carcinoma and found that only one of them showed an immunohistochemical phenotype indicative of an epithelial tumor (Ker+, HMB45-). Three tumors exhibited a phenotype compatible with the monotypic epithelioid variant of angiomyolipoma (HMB45+, Ker-), and two of the three patients died of metastatic disease. The last patient had unusual clinical features, and the tumor was positive both for HMB45 and keratin. It is concluded that (1) renal cell carcinoma is less common in tuberous sclerosis complex than previously believed, (2) some cases called renal cell carcinoma probably represent a monotypic, epithelioid variant of angiomyolipoma, and (3) epithelioid angiomyolipoma is a potentially malignant tumor with invasion and metastases. These findings indicate that all reported renal carcinomas in tuberous sclerosis complex, therefore, must be reevaluated.

Renal cell carcinoma: Pathological prognostic criteria

– Pathological criteria so far employed in the prognosis of renal cell carcinoma provide no clinically useful information. This paper emphasises the possibilities offered by histopathology today for tackling this clinical problem more effectively. Nuclear analysis, with objective and quantitative evaluation of the degree of distortion, may provide extremely useful information. The authors correctly classified 90% of the 50 cases of renal cell carcinoma considered and whose follow-up at 5 years was known.

Anti-melanoma monoclonal antibody HMB-45 on enhanced chemiluminescence-western blotting recognizes a 30-35 kDa melanosome-associated sialated glycoprotein

HMB-45 is an anti-melanoma monoclonal antibody widely used in diagnostic pathology owing to its great specificity in identifying poorly differentiated melanomas. In this study, by a series of sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) immunoblots with the enhanced chemiluminescent (ECL) detection method on the HU-214 melanoma cell line, we identified the antigen of HMB-45 in a protein or proteins of 30-35 kDa. Although this result is in discrepancy with the previous literature which identified the antigen as a protein of 7 or 10 kDa, a family of proteins of 25-70 kDa of as a protein of 100 kDa (gp100), the present data indicate that the antigen signal we found might be specific. Furthermore, immunoblots on neuraminidase-treated cell lysates show, in agreement with already published data, that the antigen might be a sialated glycoprotein with the sialic acid involved in the epitope. Immunoblots on partially purified melanosomes confirmed the presence of the antigen in these organelles.

Clear cell "sugar" tumor of the pancreas. A novel member of the family of lesions characterized by the presence of perivascular epithelioid cells

We report at unique, previously unreported pancreatic tumor occurring in a 60-year-old woman who was preoperative diagnosed on cytoaspiration as having clear cell carcinoma. The resected tumor consisted of a population of large epithelioid cells with clear or eosinophilic, granular cytoplasm, rich in glycogen, with nuclear pleomorphism and no mitotic activity. In spite of the epithelioid appearance, the tumor cells were negative for epithelial (CAM 5.2, KL1, AE1-AE3), endocrine (neuron-specific enolase [NSE], chromogranin A), and acinar (lipase, amylase) markers and positive for actin and melanogenesis-related marker HMB 45. Ultrastructurally, the neoplastic cells showed membrane-bound granules; no evidence of either epithelial or melanocytic differentiation was present. These morphophenotypic features have never been reported in a pancreatic tumor and overlap those of clear cell "sugar" tumor of the lung. The same morphophenotypic features are observed in a family of lesions characterized by the presence of the perivascular epithelioid cell that also includes lymphangiomyomatosis and angiomyolipoma. The present case may be considered a novel member of this family of lesions. We propose this new entity be named clear cell "sugar" tumor of the pancreas.

Carcinoma-like signet-ring cells in gastric mucosa-associated lymphoid tissue (MALT) lymphoma

We noticed the presence of epithelial signet-ring cells (SRCs) in a proportion of primary gastric B-cell lymphomas, and in some endoscopic biopsies we found it difficult to decide whether they represented an associated carcinoma. To evaluate the frequency and nature of this phenomenon, we reviewed 108 stomachs resected for primary lymphoma, including 70 mucosa-associated lymphoid tissue (MALT) and 38 non-MALT lymphomas. We found SRCs, either isolated or grouped in clusters, in 26 of 70 MALT lymphomas. The SRCs were always localized in the superficial portion of the lamina propria and associated exclusively with lymphomatous areas. Isolated and scarce SRCs were also found in four of 22 cases of polyclonal atypical lymphoid hyperplasia. Our data suggests that SRCs occurring in gastric MALT lymphomas represent a particular type of LEL in which the foveolar cells disaggregated by the lymphomatous infiltration acquire a globoid, signet-ring appearance. These "foveolar" LELs are found in 37% of MALT lymphomas and are usually associated with the more classic and constant "neck" LELs, which are localized between the foveolae and mucopeptic glands. An awareness of the existence of the foveolar LEL may help avoid overdiagnosis of SRC carcinoma on gastric endoscopic biopsies.

PSA-negative tumours of the prostate

The immunoperoxidase staining of normal and hyperplastic prostatic epithelium for Prostate Specific Antigen (PSA) is, with few exceptions, uniform and strong. In contrast to the benign tissue, most reports of prostatic adenocarcinoma demonstrated an apparent correlation between staining-variability and increasing tumour grades. Decreased PAP staining may be related to incorrect manipulation of prostatic tissue. Finally there are many tumours and pseudotumours of the prostate in which the PSA stain is regularly negative. In the differential diagnosis of prostate tumour, both PSA and PAP (Prostatic Acid Phosphatase) stains should be performed. It is mandatory that the stains be interpreted in the appropriate histologic and clinicopathologic setting with due consideration of positive and negative staining.

Clear cell ("sugar") tumor of the lung is a lesion strictly related to angiomyolipoma--the concept of a family of lesions characterized by the presence of the perivascular epithelioid cells (PEC)

We report a comparative study of 3 clear cell tumors of the lung (CCTL) and 3 angiomyolipomas (AML) of the kidney. Morphological analysis shows that the cells of CCTL are identical to the perivascular epithelioid component of AML. Phenotypically they both consistently expressed melanoma-associated antigens recognized by Moabs HMB45 and HMSA-1, while they were negative for HMSA-5. A minority of cells also expressed S-100 protein, vimentin and actin. In addition, one case of CCTL showed mature adipose tissue entrapped in the proliferation, thus suggesting an intermediate form between CCTL and AML. Based on morphological and phenotypical similarities, it is suggested that CCTL and AML belong to the same family of lesions, characterized by the presence of a peculiar muscle cell, expressing different melanoma-associated antigens.

Preoperative diagnosis of renal angiomyolipoma: fine needle aspiration cytology and immunocytochemical characterization

A preoperative diagnosis of renal angiomyolipoma (AML) is of great importance for a correct management of these patients with this tumor. In fact when the lesion is small and asymptomatic a conservative approach may be considered. We have evaluated the radiographic and fine needle aspiration cytology (FNAB) findings in 8 cases of AML. In 3 cases both radiology and cytology were suggestive of carcinoma and thus the patients underwent surgery. In one case both techniques suggested AML but surgery was performed because the lesion was large and symptomatic. In 4 cases where both radiology and cytology suggested AML no surgery was performed. Follow-up data are consistent with the benign nature of the lesions. The immunocytochemical analysis of the FNAB with a panel of antibodies including keratin, vimentin, actin and HMB-45 was indicative of AML in 7 of 8 cases, including 2 of the 3 cases misdiagnosed as carcinomas. The presence of HMB-45-positive perivascular epithelioid cells in the FNABs was the most significant finding. It is concluded that immunocytochemical analysis of FNAB with this monoclonal antibody panel can increase the accuracy of preoperative diagnosis of AML, and allow consideration of a conservative approach in selected cases.

Transbronchial biopsy in lymphangiomyomatosis of the lung. HMB45 for diagnosis

We have investigated the presence of smooth muscle cells with immunoreactivity for melanoma-related marker HMB45 in pulmonary lymphangiomyomatosis (PLAM). Of 75 lung specimens, including a variety of lesions (obtained with both transbronchial and open lung biopsies), only PLAM (six specimens from three patients) showed the presence of HMB45-positive cells. In addition, 20 specimens of normal lung were unreactive with this monoclonal antibody. It is concluded that the smooth muscle cells of PLAM regularly exhibit a peculiar phenotype, characterized by HMB45 immunoreactivity, distinct from other smooth muscle proliferations; and the histological diagnosis of PLAM can be made when only a transbronchial biopsy is available.

Basic fibroblast growth factor in human pheochromocytoma: a biochemical and immunohistochemical study

Biopsies of human normal adrenal medulla, adrenal pheochromocytoma, and chemodectoma were studied for the presence of basic fibroblast growth factor (bFGF). An immunoreactive M(r) 18,000 bFGF-like molecule was detected both in normal and neoplastic tissues. This molecule was identified as bFGF on the basis of its molecular weight, its affinity for heparin, and its capacity to induce plasminogen activator production in cultured endothelial GM 7373 cells. The levels of immunoreactive and biologically active bFGF appeared to be significantly higher in the extracts of adrenal pheochromocytoma and chemodectoma than in the extracts of normal adrenal medulla. bFGF immunostaining was detectable in the nuclei of chief (Type-I) cells and of endothelial cells both in normal adrenal medulla and in pheochromocytoma. Cytoplasmic bFGF positivity of endothelial cells was also observed in pheochromocytoma but not in normal tissue. The data are in keeping with the hypothesis that bFGF may exert autocrine and paracrine functions in the growth and neovascularization of human pheochromocytoma.

Diagnostic and therapeutic problems in multicentric renal angiomyolipoma

Multicentric renal angiomyolipoma is a rare form of benign tumor. However, its effective incidence as evaluated in autopsy studies may be as high as 8%. There are 2 main types of renal angiomyolipoma, that is isolated forms and those associated with other diseases, such as phakomatosis, polycystic kidneys and fibromuscular dysplasia. The tumor may also display malignant behavior with local invasiveness and regional lymph node involvement. However, the clinical course is benign and multicentricity is important for prognosis. Histopathological diagnosis often is difficult. Immunohistochemical analysis of surgical specimens using a panel of monoclonal antibodies, including HMB-45 and actin, enabled us to make a definitive diagnosis in 3 cases of multicentric renal angiomyolipoma.

Melanocyte-marker-HMB-45 is regularly expressed in angiomyolipoma of the kidney

HMB-45 (melanocytic cell-specific monoclonal antibody) immunoreactivity was investigated in 10 cases of angiomyolipoma (AML) (1 with massive regional lymph node involvement) of the kidney and detected in all of them. No HMB-45 immunoreactivity was found in other tumors of the region which can occasionally be confused with AML, such as renal cell carcinoma, Wilms' tumor, and retroperitoneal sarcoma (leiomyosarcoma and liposarcoma). These findings indicate that HMB-45 is not a melanocyte-restricted marker and suggest that its expression might be useful in distinguishing AML from other tumors of the kidney and retroperitoneum.

False-positive immunostaining of normal epithelia and carcinomas with ascites fluid preparations of antimelanoma monoclonal antibody HMB45

HMB45 is a melanoma-specific monoclonal antibody that has found widespread use in diagnostic pathology. Recent reports, however, have suggested that this antibody may cross-react with a small number of carcinomas and other epithelial cells. The authors tested the hypothesis that these latter reports represent examples of false-positive immunostaining by comparing the immunostaining on breast, salivary gland, and lung tumors with the following: (1) a commercial ascites preparation of this monoclonal antibody; (2) a protein A-purified antibody preparation derived from ascites fluid; and (3) supernatant fluid obtained from the hybridoma cell line. The authors found that all examples of nonmelanoma immunostaining in the carcinomas tested were eliminated with the nonascites fluid preparations, whereas strong immunostaining of melanomas was retained. The authors conclude that contaminated commercial ascites fluid preparations of HMB45 may account for most, if not all, of the reports of nonmelanoma immunostaining with HMB45.