Histogenesis of sarcomatoid urothelial carcinoma of the urinary bladder: evidence for a common clonal origin with divergent differentiation.

The histogenesis of sarcomatoid urothelial carcinoma, a rare neoplasm with bidirectional epithelial and mesenchymal differentiation, has been a matter of controversy. To clarify its origin, we analysed the status of X-chromosome inactivation in sarcomatoid urothelial carcinomas from 10 female patients and examined losses of heterozygosity (LOH) in these specimens and in additional 20 tumours from male patients. Six polymorphic microsatellite markers where genetic alterations occur frequently in early or advanced stages of urothelial carcinomas, including D3S3050, D8S261, IFNA, D9S177, D11S569 and TP53, were investigated in the current study. The identical pattern of non-random X-chromosome inactivation in both carcinomatous and sarcomatous components was identified in five of eight informative female patients, and the remaining three informative cases showed a random, but concordant, pattern of X-chromosome inactivation. The concordant X-chromosome inactivation results in all eight informative cases support the concept of a monoclonal origin of both components of this biphasic neoplasm. Among the tumours demonstrating loss of heterozygosity, high incidences of an identical pattern of allelic loss between carcinomatous and sarcomatous components were identified in genetic alterations associated with early carcinogenesis: 86% at D8S261, 78% at D11S569, 75% at D9S177 and 57% at IFNA. In contrast, concordant LOH patterns were less frequently observed for microsatellites related to advanced carcinogenesis: only 40% at D3S3050 and 40% at TP53. The significant overlap of loss of heterozygosity supports a monoclonal cell origin and suggests that clonal divergence may occur during tumour progression and differentiation. Divergent patterns of discordant allelic loss of microsatellite markers imply that heterogeneous pathogenetic pathways may exist in the evolution of this enigmatic neoplasm.

Overexpression of Pim-1 during progression of prostatic adenocarcinoma.

AIMS: Pim-1 is a serine/threonine kinase that has been shown to play an integral role in the development of a number of human cancers, such as haematolymphoid malignancies. Recently, evidence has shown Pim-1 to be important in prostatic carcinogenesis. In order to further our understanding of its role in prostate cancer, we investigated Pim-1 expression in normal, premalignant, and malignant prostate tissue. METHODS: Using immunohistochemistry, Pim-1 expression was analysed in prostate tissue from 120 radical prostatectomy specimens. In each case, Pim-1 staining was evaluated in benign prostatic epithelium, high grade prostatic intraepithelial neoplasia (PIN), and prostatic adenocarcinoma. The number of positively staining cells was estimated, and the intensity of staining was scored on a scale of 0 to 3+. RESULTS: Pim-1 immunoreactivity was identified in 120 cases (100%) of adenocarcinoma, 120 cases (100%) of high grade PIN, and 62 cases (52%) of benign glands. The number of cells staining in benign epithelium (mean 34%) was much lower than that in high grade PIN (mean 80%; p<0.0001) or adenocarcinoma (mean, 84%; p<0.0001). There was no significant difference between high grade PIN and adenocarcinoma in the percentage of cells staining positively for Pim-1 (p = 0.34). The staining intensity for Pim-1 was significantly lower in benign prostatic epithelium than in PIN and adenocarcinoma (p<0.001). There was no statistically significant correlation between the level of Pim-1 expression and Gleason score, patient age, tumour stage, lymph node metastasis, perineural invasion, vascular invasion, surgical margin status, extraprostatic extension, or seminal vesicle invasion. CONCLUSIONS: Pim-1 expression is elevated in PIN and prostatic adenocarcinoma compared with benign prostatic epithelium. This finding suggests that upregulation of Pim-1 may play a role in prostatic neoplasia.

Molecular genetic evidence for different clonal origin of components of human renal angiomyolipomas.

Renal angiomyolipoma is a benign neoplasm composed of variable proportions of blood vessels, smooth muscle, and adipose tissue. Smooth muscle, adipose tissue, blood vessels, and adjacent normal kidney tissue were separately microdissected from sections prepared from formalin-fixed, paraffin-processed tissues from angiomyolipomas from 18 women. X chromosome inactivation analysis using the methylation pattern at exon 1 of the human androgen receptor gene on chromosome Xq11-12 was used to study the clonal origin of each component. Nonrandom inactivation of X chromosomes was found in six of the 15 informative tumors. The smooth muscle and adipose tissue showed differing patterns of nonrandom inactivation of X chromosomes in five angiomyolipomas and the same pattern of nonrandom inactivation of X chromosomes in one. Samples from the blood vessels showed random inactivation of X chromosomes in all informative cases. Our data showed that the adipose tissue and smooth muscle cells of renal angiomyolipoma are both monoclonal but may arise independently. The coexistence of tumor subclones with morphologic heterogeneity can lead to the formation of a clinically detectable tumor.

Metanephric adenosarcoma in a young adult: morphologic, immunophenotypic, ultrastructural, and fluorescence in situ hybridization analyses: a case report and review of the literature.

Metanephric neoplasms are uncommon renal tumors that arise in both children and adults. They may be composed of small epithelial cells or benign stroma, or both, and are termed metanephric adenoma, metanephric stromal tumor, or metanephric adenofibroma, respectively. Thus far, these tumors have been known for their benign behavior. We present the case of a 21-year-old woman who developed a neoplasm composed of a renal epithelial component identical to metanephric adenoma combined with a malignant spindle cell sarcoma. The epithelial component was positive for pankeratin AE1/3, whereas the sarcomatous component was negative for epithelial markers and positive for vimentin, CD34, and CD117. No smooth muscle differentiation was apparent in the sarcoma by immunohistochemistry or ultrastructural analysis. By fluorescent in situ hybridization analysis of the sarcomatous component there was monosomy of the X chromosome, but no apparent variation from the normal diploid pattern for chromosomes 3, 7, 12, and 17. We conclude that the spectrum of metanephric neoplasia should be expanded to include malignant stromal variants, and we propose the term "metanephric adenosarcoma" for the present case.

Predicting cancer progression in patients with penile squamous cell carcinoma: the importance of depth of invasion and vascular invasion.

The ability to predict cancer progression may help the clinical management of patients with penile squamous cell carcinoma. We studied 22 cases of squamous cell carcinoma of the penis diagnosed between 1989 and 1998. The depth of invasion was measured from the basement membrane of the squamous epithelium to the deepest invasive cancer cells. Cancer progression was defined as the development of lymph node metastasis or distant metastasis. The mean patient age was 63 years and the mean follow-up was 28 months. Ten patients developed cancer progression. The mean depth of invasion among patients with cancer progression was 9.8 mM, as compared to the mean depth of invasion of 4.0 mM among those patients without cancer progression (P =.02). Vascular invasion was also predictive of cancer progression (P =.02). Metastases developed in the majority (6 out of 7) of cases invading more than 6 mM, but developed only in a minority (4 out of 15) of cases invading 6 mM or less. We conclude that depth of invasion and vascular invasion are significant predictors of cancer progression for penile squamous cell carcinoma.

Molecular evidence for the independent origin of extra-ovarian papillary serous tumors of low malignant potential.

BACKGROUND: Molecular data suggest that peritoneal tumors in women with advanced-stage ovarian papillary serous adenocarcinoma are monoclonal in origin. Whether the same is true for ovarian tumors of low malignant potential is not known. We compared peritoneal and ovarian tumors from women with advanced-stage ovarian papillary serous tumors of low malignant potential to determine whether the peritoneal tumors arose from the same clone as the ovarian tumors. METHODS: We studied the clonality of 73 peritoneal and ovarian tumors from 18 women with advanced-stage ovarian papillary serous tumors of low malignant potential. Formalin-fixed, paraffin-embedded tumors and representative normal tissues were sectioned and stained with hematoxylin-eosin, representative sections from separate tumors were manually microdissected, genomic DNA was extracted from the microdissected tumors, and the polymerase chain reaction was used to amplify a CAG polymorphic site in the human androgen receptor locus on the X chromosome to determine the inactivation pattern of the X chromosome and the clonality of the tumors. RESULTS: The pattern of X-chromosome inactivation could be determined from the tumors of 13 of 18 patients. Of the 13 patients, seven (54%) had nonrandom inactivation of the X chromosome, and six of the seven had different inactivation patterns in the peritoneal and ovarian tumors. Three of these patients also had different patterns of nonrandom X-chromosome inactivation in tumors from each ovary. The remaining six patients had random patterns of X-chromosome inactivation in the peritoneal and ovarian tumors. CONCLUSIONS: Our data suggest that peritoneal and ovarian tumors of low malignant potential arise independently.

Morphologic typing of papillary renal cell carcinoma: comparison of growth kinetics and patient survival in 66 cases.

Whereas papillary renal cell carcinoma is now established as a subtype of renal cell neoplasia, division of these tumors into 2 distinctive morphotypes has been proposed. Type 1 tumors have cells with scanty pale cytoplasm arranged in a single layer on the basement membrane of papillary cores. In these tumors, psammoma bodies and foamy macrophages are frequently seen, and the tumors frequently express cytokeratin 7. Type 2 tumor cells have pseudostratified nuclei and usually have voluminous eosinophilic cytoplasm. Recent studies have supported this subclassification of papillary renal cell carcinoma by demonstrating differing genotypes for type 1 and 2 tumors. To further study the subclassification of papillary renal carcinoma, we compared clinical features, nuclear grade, stage, tumor growth kinetics, and survival in a series of 50 type 1 and 16 type 2 papillary renal cell carcinomas. Comparison of patient age at presentation, sex, and primary tumor size shows no significant difference between the 2 tumor types. Type 1 tumors were of significantly lower Fuhrman grade (P =.0001) and higher Robson stage (P =.009) than type 2 tumors. There was no significant difference when tumors were staged according to the TNM classification. Assessment of tumor growth kinetics showed significantly different mean silver-staining nucleolar organizer region (AgNOR) scores and Ki-67 indices (AgNOR type 1, 3.83, type 2, 7.24, P =.0001; Ki-67 type 1, 3.17%, type 2, 6.01%, P =.0002). Multivariate analysis showed tumor type (P =.03), presence of metastases (P =.04), AgNOR score (P =.001), and Ki-67 index (P =.03) to be independently associated with survival. These results provide evidence of the clinical utility of dividing papillary renal cell carcinomas into 2 types according to histologic characteristics.

Mixed epithelial and stromal tumor of the kidney lacks the genetic alterations of cellular congenital mesoblastic nephroma.

Mixed epithelial and stromal tumor of the kidney is a recently recognized neoplasm that occurs almost exclusively in perimenopausal women. Because it frequently contains areas of smooth muscle in which epithelial structures are embedded, some have concluded that it is the adult form of congenital mesoblastic nephroma. Others have concluded that the morphology and epidemiology of mixed epithelial and stromal tumor indicate that it is unrelated to congenital mesoblastic nephroma. Although the genetic alterations of mixed epithelial and stromal tumor have not been previously elucidated, much is known about the genetic alterations of cellular congenital mesoblastic nephroma. The present study was undertaken to determine if mixed epithelial and stromal tumors have any of the genetic alterations recognized as typical of cellular congenital mesoblastic nephroma. RNA extraction was performed on formalin-fixed, paraffin-embedded tissue from 7 mixed epithelial and stromal tumors followed by reverse-transcription polymerase chain reaction to detect the ETV6-NTRK3 gene fusion. Fluorescent in situ hybridization with centromere-specific probes for chromosomes 8, 11, and 17 was performed to evaluate polyploidy of these chromosomes in 11 cases of mixed epithelial and stromal tumor. None of the mixed epithelial and stromal tumors showed any of these genetic alterations. We conclude that mixed epithelial and stromal tumor of the kidney lacks the genetic alterations typical of cellular congenital mesoblastic nephroma, is unrelated to it, and the appellation "adult mesoblastic nephroma" should not be used for these tumors.

Cytokeratin 7 and cytokeratin 20 in primary urinary bladder carcinoma and matched lymph node metastasis.

BACKGROUND: -Cytokeratin 7 (CK7) and cytokeratin 20 (CK20) are 2 types of intermediate filament protein. Expression of CK7 is seen in the majority of primary urinary bladder carcinomas. CK20 is restricted to superficial and occasional intermediate cells of the normal urothelium of the bladder. Aberrant CK20 expression has been documented in urothelial carcinoma and has proved useful as an ancillary diagnostic aid for urinary bladder tumor. Our hypothesis is that the pattern of CK7 and CK20 expression in metastatic urothelial carcinoma duplicates the expression of the same markers in the primary tumors. Therefore, immunohistochemical staining of metastatic tumors for these 2 markers may be helpful for differential diagnosis in ambiguous metastatic tumor deposits. OBJECTIVE: -To determine the concordance of CK7 and CK20 expression in primary bladder urothelial carcinoma and the matched lymph node metastasis. DESIGN: -We studied 26 patients with lymph node metastases who underwent radical cystectomy and bilateral lymphadenectomy for bladder carcinoma. Immunohistochemical staining for CK7 and CK20 was performed on formalin-fixed paraffin-embedded tissues containing primary cancers and lymph node metastases. RESULTS: -In all cases, there was a concordant expression of CK20 in the primary cancer and its matched lymph node metastasis. Twelve cases (46%) showed positive CK20 immunoreactivity in the primary tumor and its matched lymph node metastases, whereas 14 cases (54%) were negative for CK20 in both the primary tumor and lymph node metastasis. All cases showed positive CK7 immunoreactivity in the primary cancers and matched lymph node metastases. CONCLUSIONS: -CK20 immunoreactivity is reliably observed in metastases from bladder cancer when the primary tumor expresses CK20.

Concurrent angiomyolipoma and renal cell neoplasia: a study of 36 cases.

Little is known about the association of angiomyolipoma and adult renal-cell neoplasia. We studied the clinicopathologic features of 36 patients with concurrent angiomyolipoma and renal-cell neoplasia from the consultation and surgical pathology files of nine institutions. HMB-45 immunoreactivity was analyzed in both neoplasms. Twenty-five sporadic cases of patients with angiomyolipoma and renal-cell neoplasia and 11 cases of patients with tuberous sclerosis, as defined by Gomez' criteria, had mean ages of 59 and 53 years, respectively, and female-male ratios of 2:1 and 5:1, respectively. The mean size of the angiomyolipomas was 1 cm in the sporadic cases and 3 cm in those patients with tuberous sclerosis (medians: 0.5 and 3 cm, respectively, P =.002). The mean sizes of the renal-cell neoplasms were 5 cm in sporadic cases and 6 cm in patients with tuberous sclerosis (medians: 4 and 5 cm, respectively; P =.88). In both clinical settings, angiomyolipoma was more commonly the incidental tumor. Clear-cell (conventional) renal-cell carcinoma was the most common renal-cell neoplasm in both groups of patients, accounting for approximately two thirds of the tumors. In patients with tuberous sclerosis, 27% of renal-cell neoplasms were oncocytomas, compared with 8% in sporadic cases (P =.15). Papillary neoplasia, chromophobe, and collecting-duct renal-cell carcinoma were found only in sporadic cases. All of the 22 renal-cell neoplasms studied were negative for HMB-45, whereas all 25 angiomyolipomas studied were positive.

Immunohistochemical study of microphthalmia transcription factor and tyrosinase in angiomyolipoma of the kidney, renal cell carcinoma, and renal and retroperitoneal sarcomas: comparative evaluation with traditional diagnostic markers.

Angiomyolipoma has a unique immunophenotype with co-expression of muscle-specific actin and melanocytic markers such as HMB-45 and Melan-A. The most recently developed melanocytic markers, microphthalmia transcription factor and tyrosinase, have not been studied in the diagnosis of angiomyolipoma. We tested 29 renal angiomyolipomas (21 classic histology, 4 epithelioid variants, 2 lipomatous variants, and 2 leiomyomatous variants) with an immunohistochemical panel, including microphthalmia transcription factor, tyrosinase, HMB-45, Melan-A, and muscle-specific actin. Results were compared with 15 renal cell carcinomas (9 conventional types, 6 with sarcomatoid change), 2 leiomyosarcomas, 5 liposarcomas, and 1 unclassified high-grade sarcoma. Microphthalmia transcription factor expression was seen in 22 of 29 angiomyolipomas, one renal cell carcinoma, and one well-differentiated liposarcoma (that is, 2 of 23 non-angiomyolipomas; sensitivity 75%, specificity 91%). Tyrosinase expression was seen in 4 of 29 angiomyolipomas and 0 of 23 non-angiomyolipomas (sensitivity 14%, specificity 100%). HMB-45 was positive in 24 of 29 angiomyolipomas and 0 of 23 non-angiomyolipomas (sensitivity 83%, specificity 100%). Melan-A was expressed by 25 of 29 angiomyolipomas and 0 of 23 non-angiomyolipomas (sensitivity 86%, specificity 100%). Muscle-specific actin was expressed by 29 of 29 angiomyolipomas and 2 of 23 non-angiomyolipomas (both leiomyosarcomas; sensitivity 100%, specificity 91% [100% excluding leiomyosarcomas]). Microphthalmia transcription factor showed the most widespread staining in angiomyolipoma (50% of cases staining more than half of the tumor cells) followed by Melan-A (24% of cases staining more than 50%). Only three cases showed positivity for all four melanocytic markers, while in one case each only microphthalmia transcription factor and Melan-A were positive. We conclude that microphthalmia transcription factor, but not tyrosinase immunostaining, has a sensitivity and specificity that rivals those of the established markers, HMB-45 and Melan-A, in the diagnosis of angiomyolipoma. Our data supports the use of a panel in difficult cases that includes antibodies to microphthalmia transcription factor, either Melan-A or HMB-45, and muscle-specific actin to provide the best mix of high sensitivity, high specificity, nuclear and cytoplasmic immunolocalization, and widespread staining of cells within a given tumor.

Ultrastructural observations on mitochondria and microvesicles in renal oncocytoma, chromophobe renal cell carcinoma, and eosinophilic variant of conventional (clear cell) renal cell carcinoma.

On light microscopic examination, the morphologically overlapping features of granular eosinophilic cytoplasm in renal oncocytoma and the eosinophilic variants of chromophobe renal cell carcinoma and conventional (clear cell) renal cell carcinoma may pose difficulties in diagnosis. We investigated the ultrastructure of 5 renal oncocytomas, 7 eosinophilic variants of chromophobe renal cell carcinoma, and 5 eosinophilic variants of conventional (clear cell) renal cell carcinoma. Special attention was paid to mitochondria and microvesicles and interrelations thereof. The electron microscopic features were correlated with the light microscopic findings. All of the tumors had abundant mitochondria. Although abundant microvesicles were present in all of the chromophobe renal cell carcinomas, scant numbers of microvesicles were also sometimes present in renal oncocytomas (2 of 5) and in the eosinophilic variant of conventional (clear cell) renal cell carcinoma (1 of 5). The mitochondria in all three types of renal neoplasms studied differed in morphology, being predominantly uniform and round with predominantly lamellar cristae in renal oncocytoma, variable in shape and size with predominantly tubulocystic cristae in chromophobe renal cell carcinoma, and swollen and pleomorphic with rarefied matrix and attenuated cristae in the eosinophilic variant of conventional (clear cell) renal cell carcinoma. Variable numbers of mitochondria in all of the chromophobe renal cell carcinomas had outpouchings of the outer membranes, some of which carried parts of inner membrane within them. These outpouchings closely resembled the nearby cytoplasmic microvesicles, as did the tubulocystic cristae of the mitochondria. Some microvesicles contained homogeneous, electron-dense, finely granular matrix, similar to that seen in mitochondria. In one of seven chromophobe renal cell carcinomas, microvesicles were present in rough endoplasmic reticulum, and in two others, mitochondria were present within some vesicles. These features strongly suggest a close relationship between the microvesicles and mitochondria. Based on the role of vesicle formation in normal mitochondriogenesis, and some of our observations, we propose that defective mitochondriogenesis may be the source of microvesicles in chromophobe renal cell carcinomas.

Mixed epithelial and stromal tumor of the kidney.

We describe the clinicopathologic features of 12 patients with a distinctive tumor of the kidney characterized by a mixture of epithelial and stromal elements that form solid and cystic growth patterns. Similar tumors were reported previously in the literature under various names, including adult mesoblastic nephroma. All but one of the patients were women. The only man had a long history of treatment with lupron and diethylstilbesterol. Seven of the women had histories of long-term oral estrogen use of whom six had undergone total abdominal hysterectomy and bilateral salpingo-oophorectomy several years prior, and the seventh patient had been using oral contraceptives for many years. Another woman had this operation but did not receive any hormone therapy. Ages ranged from 31 to 71 years (mean, 56 yrs). Six patients presented with symptoms, including pain and infections attributable to mass effect, and in six the tumor was detected incidentally. Grossly, the tumors were well-circumscribed (mean size, 6 cm; range, 3-12 cm) and consisted of solid and cystic components, most often in equal proportions but in variable distribution. Microscopically, the spindle cell component ranged in appearance from scar-like fibrous tissue to leiomyoma-like interlacing fascicles; usually there was a mixture of both. More cellular foci reminiscent of ovarian stroma or solitary fibrous tumor were also present. No blastema was present. Epithelial elements (composed of clusters of tubules with variable lining) were scattered amidst the spindle cells, and focally transformed into large cysts lined by cells with abundant pink cytoplasm and a hobnail appearance. Immature epithelial elements typical of Wilms' tumor were not present. Muscle markers (desmin and smooth muscle actin) were positive diffusely and strongly in the spindle cells of all tumors, whereas HMB-45 and CD34 were absent. Estrogen receptors were detected in the nuclei of spindle cells in seven tumors and progesterone receptors in three. The distinctive clinicopathologic characteristics of these lesions warrant their classification as a separate category of kidney tumor. We suggest the descriptive term "mixed epithelial and stromal tumor" for this group until its nature and relationship to other kidney lesions are further clarified. Its preponderance in females with a history of long-term estrogen replacement and the history of long-term sex-steroid use in the only male patient, combined with the frequent content of estrogen and progesterone receptors in the spindle cells, suggest that the hormonal milieu plays a role in the evolution of these tumors. The clinical and pathologic parallels with mucinous cystic tumors of pancreas and liver raise the possibility of a common pathogenetic mechanism that may be linked to the periductal fetal mesenchyme. We think this entity is a benign composite neoplasm in which stroma and epithelium are both integral neoplastic components.

Primary malignant melanoma of the urethra: a clinicopathologic analysis of 15 cases.

The clinical and pathologic features of 15 primary urethral melanomas occurring in patients (nine women and six men) age 44 to 96 years (mean age, 73 yrs) are described. In the men the tumor involved the distal urethra. In eight women it involved the distal urethra, usually the meatus; both the distal and proximal urethra were involved in one woman. The tumors were typically polypoid and ranged from 0.8 to 6 cm (mean, 2.6 cm) in maximum dimension. A vertical growth phase was present in all tumors, with a prominent nodular component in seven of them. A radial growth phase was seen in nine tumors. The depth of invasion ranged from 2 to 17 mm. The tumors had diffuse, nested, storiform, or mixed growth patterns. The neoplastic cells typically had abundant eosinophilic cytoplasm, large nuclei with prominent nucleoli, and brisk mitotic activity. Melanin pigment was seen in 12 tumors but was conspicuous in only six. At the time of diagnosis, 13 tumors were confined to the urethra and two patients had lymph node metastasis. Nine patients died of disease 13 to 56 months after initial diagnosis and treatment, and one patient had a local recurrence at 4 years and subsequently died of sepsis 1 year later. Three patients were alive and well at 11 months, 23 months, and 7 years. One patient died at the time of the initial operation, and one died of a ruptured aortic aneurysm at 3 years without evidence of melanoma at autopsy. Primary malignant melanomas of the urethra, one fifth of which are amelanotic, must be included in the differential diagnosis of a number of primary neoplasms that involve the urethra, including transitional cell carcinoma, sarcomatoid carcinoma, and sarcomas. Conventional prognostic factors, such as depth of invasion or tumor stage, do not seem to play as important a role in predicting survival as the mucosal location and the nodular growth present frequently in these tumors.

Thomsen-Friedenreich glycotope is expressed in developing and normal kidney but not in renal neoplasms.

The Thomsen-Friedenreich glycotope (TF) is considered a general carcinoma autoantigen and is therefore of importance in cancer diagnosis and immunotherapy. We report the distribution of the TF glycotope in developing and adult human kidney and renal neoplasms. A monoclonal antibody and the lectin amaranthin were used to study the TF and its sialylated, masked form by immunohistochemistry and immunoblotting. In developing kidney, the TF was restricted to the loop of Henle, distal tubules, and peripheral collecting ducts, whereas its sialylated form was detectable in all epithelial differentiations derived from the 2 embryonic anlagen, the metanephrogenic blastema being unreactive. This pattern was essentially preserved in adult kidney, with TF labeling beginning in the thick ascending limb and extending into the collecting ducts of outer medulla. The sialylated TF glycotope was additionally observed in ascending thin limbs. The TF was exclusively expressed in the luminal cell surface and hence was inaccessible to immune reactions. Analysis of a spectrum of renal neoplasms failed to detect the TF, with the exception of occasional staining of tubules in nephroblastoma. Moreover, the sialylated TF was only detectable in oncocytoma, chromophobe renal cell carcinoma, cystic nephroma, nephroblastoma, and nephroblastomatosis complex and occasionally in type 1 papillary renal cell carcinoma. Thus, the TF and its sialylated form are expressed in normal developing and adult kidney. However, the TF does not seem to represent a tumor-associated glycotope in human kidney, nor does it appear to be of value in diagnosis and immunotherapy of renal neoplasms.

Immunohistochemical evidence for mesothelial origin of paratesticular adenomatoid tumour.

AIMS: To investigate the histogenesis of paratesticular adenomatoid tumour by use of immunohistochemical markers for a variety of carcinomas and mesothelioma. METHODS AND RESULTS: Immunohistochemical staining of sections from 12 cases of paratesticular adenomatoid tumour was undertaken using primary antibodies to antigens expressed by benign epithelial cells and carcinoma (cytokeratin AE1/AE3, cytokeratin 34ssE12, epithelial membrane antigen, MOC-31, Ber-EP4, CEA, B72.3, LEA.135, Leu M1), stromal and vascular markers (vimentin, CD34, factor VIII), and mesothelioma-associated antigens (thrombomodulin, HBME-1, OC 125) and p53 protein. There was absence of immunohistochemical expression of epithelial/carcinoma markers MOC-31, Ber-EP4, CEA, B72.3, LEA.135, Leu M1 and to factor VIII and CD34. All tumours expressed cytokeratin AE1/AE3, epithelial membrane antigen and vimentin, with weak expression of cytokeratin 34ssE12 in 25% of tumours. Each tumour showed expression of thrombomodulin, HBME-1 and OC 125 in a membranous distribution. p53 protein expression was not detected. CONCLUSIONS: The immunohistochemical profile of paratesticular adenomatoid tumour is strongly supportive of a mesothelial cell origin.

Atypical nephrogenic metaplasia of the urinary tract: a precursor lesion?

BACKGROUND: Nephrogenic metaplasia with cytologic atypia (atypical nephrogenic metaplasia) is occasionally encountered and its biologic potential is uncertain. METHODS: The authors describe 18 cases of atypical nephrogenic metaplasia characterized by the presence of prominent cytologic atypia, including nuclear enlargement, nuclear hyperchromasia, and enlarged nucleoli. DNA ploidy analysis by digital image analysis and immunostaining for high-molecular-weight cytokeratin (34betaE12), cytokeratin 7, cytokeratin 20, carcinoembryonic antigen (CEA), epithelial membrane antigen (EMA), p53, and MIB-1 were performed in 9 cases. RESULTS: The mean patient age was 62 years (median, 65 years; range, 39-84 years). The male-to-female ratio was 2.6:1. Two patients had a history of noninvasive papillary urothelial carcinoma. The typical clinical presentation was hematuria (8 patients) and voiding symptoms (5 patients). Cystoscopic findings were suspicious for neoplasm in 7 of 13 cases. The neoplastic cells were positive for high-molecular-weight cytokeratin, cytokeratin 7, and EMA, and were usually negative for cytokeratin 20 and CEA. p53 nuclear accumulation and increased MIB-1 labeling index were seen in 4 cases. DNA ploidy analysis showed aneuploid pattern in 2 of 9 cases. The mean patient follow-up was 3.5 years (range, 0.5-10.6 years); 2 patients had recurrent nephrogenic metaplasia, and the remainder were alive without recurrence or urothelial carcinoma. CONCLUSIONS: Atypical nephrogenic metaplasia is benign; it occasionally displays substantial cytologic abnormalities of no apparent clinical significance. Awareness of the spectrum of cytologic changes within this entity is critical to prevent overdiagnosis of cancer and avoid unnecessary treatment. There is no direct evidence that links atypical nephrogenic metaplasia to cancer.

Diagnosis and classification of renal cell carcinoma.

Although substantial agreement exists in most aspects of diagnosis and staging of renal cell carcinoma, further work is needed to resolve unsettled issues regarding precursor lesions, grading, and the prediction of outcome for individual patients.

Chromosomal analysis of renal angiomyolipoma by comparative genomic hybridization: evidence for clonal origin.

Angiomyolipoma has long been considered a hamartomatous polyclonal proliferation. However, recent molecular analyses have indicated that these tumors may be clonal neoplasms rather than polyclonal proliferations. We investigated chromosomal imbalances in angiomyolipoma by comparative genomic hybridization. DNA was extracted from archival paraffin-embedded and frozen tissues of 12 angiomyolipomas (10 usual variant, two epithelioid variant). The 10 angiomyolipomas of the usual variant included bilateral tumors from one tuberous sclerosis patient. Fluorescence ratio distributions from tumor hybridizations were compared with those from control hybridizations to detect changes in DNA copy number with high sensitivity and specificity. We identified 20 chromosomal imbalances in seven sporadic angiomyolipomas, including both tumors of the epithelioid variant. The remaining five tumors, including the two angiomyolipomas from a tuberous sclerosis patient, were devoid of chromosomal imbalances. Seventy-five percent of the imbalances were partial or whole chromosomal deletions involving disparate genomic regions, some of which have previously been associated with tumors of adipose tissue and smooth muscle tumors. Four angiomyolipomas of the usual variant showed 5q deletions with a common region of deletion spanning 5q33 to q34. In two tumors, deletion on 5q was the sole abnormality. One epithelioid angiomyolipoma showed 5q gain encompassing the same region in addition to other alterations. We concluded that (1) Chromosomal imbalances are common in renal angiomyolipomas; (2) Presence of clonal genomic alterations lends further support to the neoplastic pathogenesis of these tumors; (3) The 5q33-q34 region may contain a tumor suppressor gene significant in the histogenesis of some renal angiomyolipomas.