Molecular Genetic Alterations in Renal Cell Carcinomas With Tubulocystic Pattern: Tubulocystic Renal Cell Carcinoma, Tubulocystic Renal Cell Carcinoma With Heterogenous Component and Familial Leiomyomatosis-associated Renal Cell Carcinoma. Clinicopathologic and Molecular Genetic Analysis of 15 Cases.

The characteristic morphologic spectrum of tubulocystic renal cell carcinoma (TC-RCC) may include areas resembling papillary RCC (PRCC). Our study includes 15 RCCs with tubulocystic pattern: 6 TC-RCCs, 1 RCC-high grade with tubulocystic architecture, 5 TC-RCCs with foci of PRCC, 2 with high-grade RCC (HGRCC) not otherwise specified, and 1 with a clear cell papillary RCC/renal angiomyoadenomatous tumor-like component. We analyzed aberrations of chromosomes 7, 17, and Y; mutations of VHL and FH genes; and loss of heterozygosity at chromosome 3p. Genetic analysis was performed separately in areas of classic TC-RCC and in those with other histologic patterns. The TC-RCC component demonstrated disomy of chromosome 7 in 9/15 cases, polysomy of chromosome 17 in 7/15 cases, and loss of Y in 1 case. In the PRCC component, 2/3 analyzable cases showed disomy of chromosome 7 and polysomy of chromosome 17 with normal Y. One case with focal HGRCC exhibited only disomy 7, whereas the case with clear cell papillary RCC/renal angiomyoadenomatous tumor-like pattern showed polysomies of 7 and 17, mutation of VHL, and loss of heterozygosity 3p. FH gene mutation was identified in a single case with an aggressive clinical course and predominant TC-RCC pattern. The following conclusions were drawn: (1) TC-RCC demonstrates variable status of chromosomes 7, 17, and Y even in cases with typical/uniform morphology. (2) The biological nature of PRCC/HGRCC-like areas within TC-RCC remains unclear. Our data suggest that heterogenous TC-RCCs may be associated with an adverse clinical outcome. (3) Hereditary leiomyomatosis-associated RCC can be morphologically indistinguishable from "high-grade" TC-RCC; therefore, in TC-RCC with high-grade features FH gene status should be tested.

Chromophobe renal cell carcinoma with neuroendocrine and neuroendocrine-like features. Morphologic, immunohistochemical, ultrastructural, and array comparative genomic hybridization analysis of 18 cases and review of the literature.

Chromophobe renal cell carcinoma (CRCC) with neuroendocrine differentiation (CRCCND) has only recently been described. Eighteen cases of CRCC with morphologic features suggestive of neuroendocrine differentiation were selected from among 624 CRCCs in our registry. The tissues were fixed in neutral formalin, embedded in paraffin, cut into 4- to 5-µm-thick sections, and stained with hematoxylin and eosin. As CRCC with neuroendocrine features, tumors with following morphology were suggested: (1) trabecular/palisading/ribbon-like, gyriform, insular, glandular, and solid pattern; (2) uniform polygonal cells formed in small islets; and (3) cribriform pattern in combination with palisading. Selected cases were further analyzed using immunohistochemistry, electron microscopy, array comparative genomic hybridization, and fluorescence in situ hybridization. Cases were classified as CRCCND or CRCC with neuroendocrine-like features (CRCCND-L) based on the immunohistochemical expression of neuroendocrine markers: CRCCND, 4 cases, age range 49 to 79 years, size ranged from 2.2 to 22 cm, and CRCCND-L, 14 cases, age range 34 to 74 years, size range 3.8 to 16.5 cm. Follow-up information was available for 11 of 18 patients aged 0.5 to 12 years. Two of 4 CRCCNDs showed aggressive clinical course with metastatic spreading. Chromophobe renal cell carcinomas with neuroendocrine differentiation were focally positive for CD56 (4/4), synaptophysin (4/4), chromogranin A (1/4), and neuron-specific enolase (3/4). All 14 CRCCND-Ls were mostly negative or very weakly focally positive for some of the aforementioned markers. All 18 tumors were positive for cytokeratin 7 and CD117. Ultrastructural analysis showed poorly preserved neuroendocrine granules only in 2 of 4 analyzed CRCCNDs. Losses of chromosomes 1, 2, 6, and 10 were found in all analyzable CRCCNDs, whereas multiple losses (chromosomes 1, 2, 6, 10, 13, 17, and 21) and gains (chromosomes 4, 11, 12, 14, 15, 16, 19, and 20) were found in CRCCND-L.

Aggressive and nonaggressive translocation t(6;11) renal cell carcinoma: comparative study of 6 cases and review of the literature.

UNLABELLED: t(6;11) renal cell carcinoma (RCC) has been recognized as a rare and mostly nonaggressive tumor (NAT). The criteria for distinguishing aggressive tumors (AT) from NATs are not well established. A total of 6 cases were selected for the study. Five cases of t(6;11) RCCs behaved nonaggressively, and 1 was carcinoma with aggressive behavior. The tumors were analyzed morphologically using immunohistochemistry and by molecular-genetic methods. The specimen of aggressive t(6;11) RCC was from a 77-year-old woman who died of the disease 2.5 months after diagnosis. The specimens of nonaggressive t(6;11) RCCs were from 3 women and 2 men whose ages range between 15 and 54 years. Follow-up was available in all cases (2.5 months-8 years). The tumor size ranged from 3 to 14 cm in nonaggressive t(6;11) RCC. In the aggressive carcinoma, the tumor size was 12 cm. All tumors (6/6) were well circumscribed. Aggressive t(6;11) RCC was widely necrotic. Six (100%) of 6 all tumors displayed a solid/alveolar architecture with occasional tubules and pseudorosettes. Pseudopapillary formations lined by bizarre polymorphic cells were found focally in the aggressive t(6;11) RCC case. Mitoses, though rare, were found as well. All cases (AT and NAT) were positive for HMB-45, Melan-A, Cathepsin K, and cytokeratins. CD117 positivity was seen in 4 of 5 NATs, as well as in the primary and metastatic lesions of the AT. mTOR was positive in 2 of 5 NATs and vimentin in 4 of 5 NATs. Vimentin was negative in the primary lesion of the AT, as well as in the metastasis found in the adrenal gland. Translocation t(6;11)(Alpha-TFEB) or TFEB break was detected in 4 of 5 NATs and in the AT case. Aggressive tumor showed amplification of TFEB locus. Losses of part of chromosome 1 and chromosome 22 were found in 1 of 5 NATs and in the AT. CONCLUSIONS: (1) Aggressive t(6;11) RCCs generally occur in the older population in comparison with their indolent counterparts. (2) In regard to the histologic findings in ATs, 3 of 5 so far published cases were morphologically not typical for t(6;11) RCC. Of the 3 cases, 2 cases lacked a small cell component and 1 closely mimicked clear cell-type RCC. (3) Necroses were only present in aggressive t(6;11) RCC. (4) Amplification of TFEB locus was also found only in the aggressive t(6;11) RCC.

Renal cell carcinoma with leiomyomatous stroma--further immunohistochemical and molecular genetic characteristics of unusual entity.

UNLABELLED: Renal cell carcinoma (RCC) with leiomyomatous stroma (RCCLS) is a recently recognized entity with indolent biological behavior. The diagnostic implication of absence/presence of VHL gene mutation, VHL hypermethylation, or/and loss of heterozygosity of chromosome 3p (LOH 3p) is widely discussed. Criteria for establishing a diagnosis of RCCLS are still lacking. Fifteen RCCLSs were retrieved from our registry. The cases were studied with consideration to the morphology, immunohistochemistry, and molecular genetics. All cases were composed of low-grade epithelial cells with clear cytoplasm arranged in nests intermingled with abundant leiomyomatous stroma. Age range of the patients was 33 to 78 years. The tumor size ranged from 1.5 to 11 cm. Six of the patients were males, and 9, females. Of the 15 tumors sent for molecular genetic testing, only 12 cases were analyzable. All cases were analyzable immunohistochemically. Of 12 of these cases, 5 showed complete absence of VHL gene mutation, VHL hypermethylation, and LOH 3p. Of these 5 cases, 3 were positive for cytokeratin 7 (CK 7). All of the 5 cases were positive for carbonic anhydrase 9, vimentin, and CD10. The remaining 7 of 12 genetically analyzable cases were found to have had VHL hypermethylation, LOH 3p, VHL gene mutation, or a combination of the former 2 characteristics. These 7 cases were positive for vimentin. Variable reactivity was found for CK 7, carbonic anhydrase 9, α-methylacyl-CoA racemase, and CD10. In 1 of these 7 cases, gains on chromosomes 7 and 17 as well as hypermethylation of VHL gene were found. This case was considered as clear cell RCC with aberrant status of chromosomes 7 and 17. CONCLUSIONS: (1) Leiomyomatous stroma is not specific for the so called RCCLS. It can be seen also in otherwise typical clear cell RCCs. (2) There are no characteristic morphological/immunohistochemical features unique for "RCCLS." (3) Our results indicate that only tumors with the absence of the VHL gene mutation, hypermethylation, and LOH 3p can be diagnosed as RCCLS. (4) Relation of RCCs with a prominent smooth muscle stroma to the renal angiomyoadenomatous tumor/clear cell papillary (tubopapillary) RCC is not clearly evident from our study and has to be further analyzed on larger cohort of the patients.

Foamy cell (hibernoma-like) change is a rare histopathological feature in renal cell carcinoma.

We report nine patients (seven males and two females, median age 64 years (range 51-79 years)) with a renal cell carcinoma, each of which contained a significant component of neoplastic epithelial cells with a striking microvacuolated (hibernoma-like) cytoplasmic appearance. Tumor sizes ranged from 1.5 to 8.0 cm (mean 4.2 cm, median 4.3 cm). The basic architecture of the tumors was solid-alveolar in two cases (classified as renal cell carcinoma-not otherwise specified (NOS)) and papillary in seven cases (classified as papillary renal cell carcinoma NOS). The nuclear grade according to the Fuhrman grading system was three in all cases. By immunohistochemistry, the cells with microvacuolated cytopasm and significantly expressed adipophilin and anti-mitochondrial antigen in a similar cytoplasmic pattern. On ultrastructural examination, the cytoplasm of the neoplastic epithelial cells was packed with distended mitochondria, most of which displayed lamellated cristae. Numerous microvesicles were dispersed between the mitochondria. No mutations in the succinate dehydrogenase B gene were identified. Based on our findings, we propose that the mechanism behind this phenomenon is an abnormal intracellular processing of lipids. No aggressive behavior was observed in six out of nine patients with available follow-up information.

The leiomyomatous stroma in renal cell carcinomas is polyclonal and not part of the neoplastic process.

Some renal epithelial neoplasms, such as renal angiomyoadenomatous tumor, clear cell papillary renal cell carcinoma and renal cell carcinoma with smooth muscle stroma, contain a variably prominent smooth muscle stromal component. Whether or not this leiomyomatous stroma is part of the neoplastic proliferation has not been firmly established. We studied the clonality status of 14 renal cell carcinomas with a prominent smooth muscle stromal component (four renal angiomyoadenomatous tumors/clear cell papillary carcinomas, five clear cell carcinomas, two papillary carcinomas, and three renal cell carcinomas with smooth muscle rich stroma) using the human androgen receptor assay (HUMARA). We found the leiomyomatous stromal component in all analyzable (8/14) cases to be polyclonal and therefore reactive rather than neoplastic. Based on morphological observations, we propose that the non-neoplastic leiomyomatous stromal component is likely derived from smooth muscle cells of large caliber veins located at the peripheral capsular region or within the collagenous septae of the tumors.

Choriogonadotropin positive seminoma-a clinicopathological and molecular genetic study of 15 cases.

The presence of human chorionic gonadotropin (hCG) positive syncytiotrophoblastic cells (STC) in classic seminoma (CS) is well documented. CS with extensive hCG positive, non-syncytiotrophoblastic tumour cells (without STC) is exceptionally rare. In this study, we present 15 such cases. 168 CSs were retrieved from the Plzen Tumor registry. Cases of mixed germ cell tumors (with CS) and CSs with typical STC were excluded. Cases with completely embedded tumor mass were selected for further study and immunohistochemically examined with anti-hCG. Positive cases were further analyzed by reverse transcriptase polymerase chain reaction. Two groups of hCG-positive CSs were identified. Group 1 comprised 10 patients with a mean patient age of 37.7 years and mean tumor size of 4.96 cm. Eight cases were pT1 (TMN 2009) and 2 cases pT3a. Blood levels of hCG were elevated in 6 of the 10 patients preoperatively. In 2 patients the blood level of hCG was not tested. Mean follow-up period was 6.1 years. No metastatic behavior was noted. All tumors were extensively immunoreactive for hCG in more than 60% of tumor cells. The expression of hCG beta subunit (CGB)-mRNA in tumor tissue was documented. Group 2: Comprised 5 patients with a mean age was 34 years. Mean tumor size was 4.7 cm. Four cases were stage pT1 and 1 case was pT2. The mean follow-up period was 3.1 years. No metastatic behavior was noted. Preoperative blood levels of hCG were elevated in 1/5 of the patient. Strong hCG positivity was limited to scattered single tumor cells distributed throughout the entire tumor. Only weak expression of CGB mRNA was detected. We can conclude that immunohistochemical detection of expression of hCG in CS is not limited to syncytiotrophoblastic cells. In this study, we report two immunohistochemical patterns of hCG expression in classic seminomas: diffuse hCG staining in the majority of tumor cells and scattered hCG-positive cells within the tumor.

Nephrogenic adenoma of the urinary tract: clinical, histological, and immunohistochemical characteristics.

Nephrogenic adenoma is a benign condition of the urinary tract resulting from the displacement and seeding of renal tubular cells from the renal pelvis to the urethra. A retrospective series of 134 cases collected from four hospitals in three different countries was analyzed in this study. Recorded clinical data included age and sex, topography, urological antecedents, coexistent lesions, and follow-up. Cytonuclear and architectural features were reviewed, and PAX-8, p63, PSMA, S100A1, CEA, EMA, CD117, cannabinoid receptor CB1, AMACR, E-cadherin, and CD10 antibodies were included in an immunohistochemical panel. Males predominated (105 M/29 F) with an average age of 66 years (range, 14-96). Urothelial carcinoma was the most frequent clinical antecedent (43.2 %) and also the most common coexisting lesion (14 %). Tubular architecture was the most frequent pattern detected (40 %) although most cases showed a mixed pattern (45.5 %). Deep infiltrative growth into the muscularis propria occurred in two cases. EMA and PAX-8 were expressed in 100 % of nephrogenic adenomas, while E-cadherin reactivity was observed in 66.6 % of cases, cannabinoid receptor CB1 in 25 %, CD10 in 13.6 %, CD117 in 4.1 %, and AMACR in 2.7 %. For the rest of the antigens, no reactivity was found. The average time lapse between the pathological antecedent and the discovery of a nephrogenic adenoma was 32 months. We conclude that nephrogenic adenoma displays a broad spectrum of histological features that may mimic malignancy. In our experience, CB1 immunostaining adds a further argument in favor of a renal origin of this lesion. The combination of PAX-8+, p63-, and EMA + distinguishes nephrogenic adenoma from urothelial and prostate carcinoma, its most frequent malignant look-alikes.

Chromophobe renal cell carcinoma--chromosomal aberration variability and its relation to Paner grading system: an array CGH and FISH analysis of 37 cases.

Genetically, chromophobe renal cell carcinoma (ChRCC) is characterized by multiple chromosomal changes, especially losses. The most common losses include chromosomes 1, 2, 6, 10, 13, 17, and 21. The Fuhrman grading system lacks prognostic relevance for ChRCC, and recently, a new grading system for ChRCC was proposed by Paner. The objective of this study was to map the spectrum of chromosomal aberrations (extent and location) in a large cohort of ChRCCs and relate these findings to the Paner grading system (PGS). A large cohort of ChRCC was reviewed and graded according to the PGS. All the cases were reevaluated and separated into groups according to their PGS. The final study set was 37 patients. ChRCCs were divided into PG 1-3, sarcomatoid, and aggressive groups. "Aggressive ChRCCs" were designated cases with known metastatic activity, local recurrence, aggressive growth to the adjacent organs, or invasive growth into the renal sinus (with/without angioinvasion). Sarcomatoid tumors were divided into their epithelial and sarcomatoid component (further molecular genetic analyses were performed separately). Array comparative genome hybridization and/or fluorescence in situ hybridization analysis was applied to 42 samples from the 37 cases. Multiple losses, as well as gains, were detected in different chromosomes. Regardless of the PGS groups, the most frequently detected losses involved chromosomes 1 (27/37), 2 (26/37), 6 (23/37), 10 (26/37), 13 (19/37), and 17 (24/37). Loss of chromosome 21 was found in 12/37 cases. The most frequently detected gains were found on chromosomes 4 (22/37), 7 (24/37), 15 (20/37), 19 (22/37), and 20 (21/37). Cluster analysis showed that there is no relation between PGS and particular pattern of chromosomal changes (losses or gains) in ChRCCs. Conclusions are as follows: (1) ChRCCs showed a significantly broader spectrum of chromosomal aberrations than previously recognized. While previously published chromosomal losses were found in our cohort, gains of multiple chromosomes were also identified in a high percentage. The most frequently detected gains involved chromosomes 4, 7, 15, 19, and 20. (2) There is no relation between chromosomal numerical changes and Paner grading system.