Classification of adult renal-cell tumors, based for years on histological criteria only, has been recently updated by taking into account characteristic chromosome rearrangements and genome and transcriptome profiles identified by cytogenetic techniques, detection of fusion transcripts and by genomic analyses on DNA microarrays. Papillary carcinomas are divided into two types. Type 1 is characterized by trisomies 7 and 17, and 12, 16, and 20. Type 2 is a heterogeneous group, including a low-grade subtype corresponding to genetically evolved type 1 tumors, and a high-grade subtype, identified by its expression profile which remains to be well characterized at the genomic level. Mucinous tubular carcinoma exhibits a recurrent genomic profile with whole chromosome losses involving 1, 4, 6, 8, 9, 13, 14, 15, and 22, consequently without relationship with type 1 papillary tumors. The profile of chromophobe-cell carcinoma corresponds to the same genomic mechanism, with losses of chromosomes 1, 2, 6, 10, 13, 17, and 21, without relationship with that of oncocytoma. Juvenile carcinoma, that can occur also in adults, shows translocations involving genes of the MiTF/TFE family, TFE3, in Xp11.2, and TFEB, in 6p21. So, molecular diagnosis, either by identification of specific translocations, or by genomic profiling, can be of valuable help for typing renal tumors when histological classification is difficult.

Objective: To investigate the clinicopathologic features, diagnostic and differential diagnostic aspects of pigmented microcystic chromophobe renal cell carcinoma (ChRCC). Methods: Five cases of pigmented microcystic ChRCC were collected at Zhejiang Provincial People's Hospital from January 2013 to January 2018. The clinical features, gross and histological appearances, immunohistochemistry and prognosis were analyzed and the relevant literature was reviewed. Results: There were 3 men and 2 women with age range of 45 years to 72 years (mean 57 years). All tumors were incidentally identified by imaging examinations. Grossly, the tumors were well-demarcated and showed diameters ranging from 1.8 cm to 4.0 cm(mean 2.9 cm). On cross section, the tumors were brown to gray tan with solid cut-surface mixed with multiple cysts of variable sizes. Hemorrhage was common, central scar was not seen. Microscopically, the tumors were composed predominantly of irregular and variable-sized microcystic or tubulocystic patterns, with extensive cribriform structures formation and focal adenomatous rearrangements seen in one case each, and focal pseudo-papillary structures (lacking true fibro-vascular cores) seen in two cases. Microscopic calcifications and psammoma bodies were present in all tumors. Four tumors composed mostly of eosinophilic cells whereas 1 predominated in plant-like cells. Brown pigmentations, either intracytoplasmic or extracytoplasmic, were noted in all five cases. The tumor cells had irregular, low-grade nuclei (Paner grade: 1) frequently with binucleation and perinuclar halos. Tumor necrosis or sarcomatous transformation was not seen. By immunohistochemistry, the tumor cells expressed CK, EMA, and E-cadherin diffusely and strongly in five cases; and CK7 and CD117 diffusely in four cases. They were negative for vimentin, CD10, CA9, AMACR/P504s, TFE3, HMB45, Melan A, S-100 protein, synaptophysin and chromogranin. Partial nephrectomies were performed for all five patients; there was no tumor recurrences or metastases at a follow-up of 2 to 55 months (mean, 17 months). Conclusions: Pigmented microcystic ChRCC is a rare histological variant of ChRCC with relatively indolent behavior, and shows morphologic heterogeneity which can elicit a wide range of differential diagnoses. Careful attentions to search for typical features of classic ChRCC with the use of immunohistochemistry can help to distinguish this tumor from its many mimickers.

OBJECTIVE

To study the clinicopathologic features of clear cell papillary renal cell carcinoma (CCPRCC).

METHODS

The clinical, morphologic and immunohistochemical characteristics of 6 cases of CCPRCC were reviewed, with analysis of follow-up data.

RESULTS

There were altogether 3 men and 3 women. The mean age of patients was 56 years. The size of tumors ranged from 1.0 to 4.5 cm in greatest dimension. They had solid or solid-cystic cut surface. Histologically, the tumors were encapsulated and showed several morphologic patterns, with tubules, papillae, acini, interconnecting ribbons and macro/microcysts lined by single layer of cells with clear or small amount of eosinophilic cytoplasm and low-grade nuclei (corresponding to Fuhrman grade 1 or 2). Mitotic figures were rarely seen. Characteristically, there was linear arrangement of the nuclei away from the basement membrane, conferring an appearance similar to that of endometrial glands in early secretory phase. Tubules and cysts contained serosanguineous fluid or colloid-like secretion were identified. No foamy histiocytes, psammomatous calcifications or hemosiderin was present in the papillary areas. Two of the tumors showed focal or extensive angioleiomyoma/leiomyoma-like components. No coagulative necrosis, sarcomatoid dedifferentiation, nor microscopic vascular invasion was observed. Immunohistochemically, all tumors showed strong co-expression of CK7 and CA9 (with characteristic "goblet" staining pattern). The staining for EMA, CK (AE1/AE3), vimentin, CK8, CK18, CK19 and PAX-8 were also positive in all cases. Ki-67 was expressed in less than or about 5% of the tumor cell nuclei. The staining for CD10, P504S, CD117, TFE3 and TFEB was negative. Follow-up data were available in all patients, with mean duration of 14 months (range = 7 to 27 months). All of the patients were disease-free after operation.

CONCLUSIONS

CCPRCC is a special type of low-grade renal neoplasm with characteristic histopathologic and immunohistochemical features. It needs to be distinguished from clear cell renal cell carcinoma or papillary renal cell carcinoma.

Objective: To study clinical pathological characteristics, immunohistochemical, molecular genetical changes and prognosis in pediatric eosinophilic solid and cystic renal cell carcinoma (ESC RCC) with TSC2 gene mutations. Methods: The tissue samples were collected from two pediatric ESC RCC patients between 2017 and 2018. The tissues were subjected to histological examination and immunohistochemistry using EnVision system. The TFE3, TFEB gene rearrangements were tested using FISH and molecular genetic study. The paraffin sections were used for DNA extraction, PCR amplification and NGS sequencing. Results: The two patients with ESC RCC were both male, aged at 9 years and 8 months, and 13 years, respectively. The tumors were from the right kidney, 5 cm and 7 cm in size, respectively, with solid and cystic changes in cross section, and grey-reddish or grey-whitish fish meat appearance. Microscopic observation revealed the tumors had fibrous capsules, which were infiltrated by the tumor cells. The tumor cells were diffusely distributed, round-shaped, or polygon-shaped, and had voluminous cytoplasm, eosinophilic cytoplasm, various sizes of vacuoles and clear cell-like appearance. There were papillary structures in some areas, with visible fiber septa. The nuclei were round and vesicular, with multi-nucleated cells and megakaryocytes. The mitoses were not seen. A few cystic structures were visible in different sizes, and capsule walls were covered with a single layer of spike-like tumor cells. Thick-walled blood vessels were seen in the stroma, with focal lymphocytic infiltration, eosinophilic necrosis, calcifications and cholesterol crystals. Immunohistochemistry of the tumor cells was positive for PAX8 (diffuse), CK20 (focal), CKpan (focal), CK10 (1 focal, 1 diffuse), INI1, vimentin, CD68, and Ki-67 (5%~10%); the tumor cells were negative for HMB45, S-100, Melan A, p53, desmin, TFE3, CK7, CK19, EMA, CD56, CgA, Syn, CD30, CD117, WT1 and SMA. Molecular genetic study showed that TFE3 and TFEB gene rearrangements were not detected by FISH. NGS sequencing showed TSC2 p.Lys574Ter (0.198) was found in patient one and TSC2 p.Arg406Ter (0.355) in patient two. Conclusions: ESC RCC in children is a rare disease, and can be misdiagnosed easily. It has unique pathological characteristics, and immunohistochemical, molecular and genetic changes. The prognosis is relatively good.

目的： 探讨具有TSC2基因突变的儿童嗜酸性实性和囊性肾细胞癌（ESC RCC）临床病理特征、免疫组织化学及分子遗传学特征和预后。 方法： 收集2017年至2018年2例ESC RCC临床资料，HE和免疫组织化学染色（EnVision）法进行形态学观察；荧光原位杂交检测TFE3、TFEB断裂重排基因；分子基因检测，PCR扩增，二代测序。 结果： 2例ESC RCC为男性，年龄分别9岁8个月和13岁，均发生在右肾。肿瘤大小5~7 cm，切面囊实性，灰红、灰白鱼肉样。显微镜下肿瘤具有纤维性包膜，肿瘤细胞突破胞膜。肿瘤细胞弥漫分布，圆形、多边性，胞质丰富，嗜伊红，可见大小不一的空泡，呈透明细胞样；部分区域类似乳头样结构，可见纤维轴心。细胞核圆形、泡状核，易见多核及巨核细胞，核分裂象未见；少量大小不一的囊样结构，囊壁可见单层瘤细胞被覆呈钉突样。间质见厚壁血管，灶状淋巴细胞浸润；较多嗜伊红坏死，可见钙化和胆固醇结晶。免疫组织化学阳性表达：PAX8（弥漫）、细胞角蛋白（CK）20、广谱细胞角蛋白（CKpan，局灶）、CD10（1例局灶/1例弥漫）、INI1、波形蛋白、CD68阳性，Ki-67阳性指数5%~10%。HMB45、S-100蛋白、Melan A、p53、结蛋白、TFE3、CK7、CK19、上皮细胞膜抗原（EMA）、CD56、嗜铬粒素A（CgA）、突触素、CD30、CD117、WT1、平滑肌肌动蛋白（SMA）阴性。分子遗传学检测：TFE3、TFEB断裂重排阴性。二代测序：例1，TSC2 p.Lys574Ter（0.198）；例2，TSC2 p.Arg406Ter（0.355）。 结论： ESC RCC儿童发病比较罕见，容易误诊，其具有独特的病理形态学特征、免疫表型和分子遗传学改变，预后较好。.

Keywords: Child; Genetic testing; Immunohistochemistry; Kidney neoplasms.

OBJECTIVE

To study the clinicopathological features, differential diagnosis and prognosis of clear cell papillary renal cell carcinoma (CCPRCC).

METHODS

The histological, immunohistochemical, and molecular features were studied in 11 cases and follow-up data were also analyzed.

RESULTS

There were a total of 3 females and 8 males. The age of patients were ranged from 33 to 72 years(mean age 52.5 years). The diameters of tumors varied from 1cm to 4 cm. Histologically, papillary and cystic architecture were present at least focally in all tumors. The papillae were covered by small to medium-sized cuboidal cells with abundant clear cytoplasm and often showed extensive secondary branching, which were often folded and densely packed, resulting in a solid appearance. The nuclei were round and uniform in shape; nucleoli were not prominent (Fuhrman grade 1 or 2). Neither mitotic figures nor necrosis was present. All 11 cases exhibited moderate to strong positivity for CK7, CA9, vimentin, and HIF-1α, coupled with negative reactions for CD10, P504S, and TFE3. Ksp-cadherin was positively expressed in 8 cases.VHL gene mutations were not found in all 11 cases. Losses of chromosomes 3 (monoploid chromosome 3) was detected in 3 cases.

CONCLUSIONS

CCPRCC is uncommon and seemed to be an indolent tumor. The differential diagnosis should be included tumors, which harbor clear cell and papillary structure including clear cell renal cell carcinoma, papillary renal cell carcinoma, Xp11 translocation renal cell carcinoma, and CCPRCC. Immunohistochemical and molecular analysis may be help for its diagnosis.

Epithelioid hemangioendothelioma (EHE) is an uncommon low-grade malignant vascular tumor that may arise in soft tissue/bone or visceral sites such as the liver and lung. As this tumor exhibits epithelioid morphology, it frequently causes diagnostic confusion with other epithelioid vascular neoplasms as well as carcinoma. While 90% of classic EHE are driven by a WWTR1-CAMTA1 fusion gene, a histologically distinctive subset of EHE has been recently shown to harbor a different fusion gene, YAP1-TFE3. This variant is likely underrecognized given its rarity and only recent description. Notably, EHE frequently involves the liver but only one case of hepatic YAP1-TFE3 rearranged EHE has been reported to date. We present the second case of YAP1-TFE3 rearranged EHE affecting a 65-year-old woman and presenting as multiple liver masses, with characterization of the fusion gene at the transcriptomic and genomic levels. There are several educational points noted from this case. YAP1-TFE3 rearranged EHE shows distinctly vasoformative foci, unlike classic EHE and mimicking angiosarcoma or epithelioid hemangioma. The tumors cells show a histiocytoid appearance with voluminous cytoplasm, similar to other TFE3-rearranged tumors. Finally, in the liver, this tumor may in part mimic focal nodular hyperplasia of the liver which is an underrecognized diagnostic pitfall. This report highlights the key diagnostic and genetic features of this newly recognized variant of hepatic EHE to aid pathologists in appropriately classifying these tumors.

We report a renal tumor detected by prenatal ultrasound and resected at 2 months of age. This 9-cm, solid mass was composed of tubular and papillary structures lined by small, uniform epithelial cells. There was local invasion into renal parenchyma and a tumor deposit in a hilar lymph node. The tumor was immunopositive for WT1, pankeratin, and CD10; focally positive for CK7; and negative for EMA and TFE3. Based on morphology and immunophenotype, the favored diagnosis was metanephric adenoma over Wilms tumor, renal cell carcinoma, and nephrogenic rest. However, metanephric adenoma only occasionally occurs in children and has never been reported prenatally. Alternatively, this tumor might be a congenital Wilms tumor that differentiated completely. Although the nature of the tumor remains unconfirmed, resection appears to have been curative; the patient remains disease-free 18 months following surgery alone.

Background: Renal cell carcinoma (RCC) constitutes 3% of all cancers, with a higher incidence in patients with age between 60 and 70 years. RCC frequently present as a metastatic tumor at diagnosis, and bones represent one of the most frequent sites. Many cases, mainly in young patients, includes the Xp11 translocation RCC. The cytological diagnosis of Xp11 translocation RCC in adult population it is rarely performed, likely for the morphological overlap with other adult renal cell carcinoma subtypes.

Methods: We retrospectively analyze a series of 92 adult patients with metastatic bone tumors, diagnosed on fine-needle aspiration cytology (FNAC) samples, focusing mainly on the cytological, immunophenotypic and molecular features of Xp11 translocation RCC.

Results: In our series 6 of 92 (6.5%) cases were metastatic RCC (mRCC), among them 2 cases were metastasis from Xp11translocation RCC. Those cases showed a bloody background, with several groups of atypical cells arranged in syncytial groups or in papillary groups composed by atypical cells with abundant cytoplasm, with scattered clear cells. TFE3 was positive on immunocytochemical analysis and specific translocation t(Xp11.23) was detected by FISH analysis.

Conclusions: In adult patients with mRCC, it is necessary to consider also Xp11 translocation RCC among the diagnostic hypotheses. FNAC represents a valid tool to investigate bone lesions but cytological features of Xp11 translocation RCC are still poorly described and must necessarily be better defined.

Keywords: FNAC; Xp11 translocation; bone metastasis; cytology; renal cell carcinoma.

BACKGROUND

Renal carcinomas associated with Xp11.2 translocations/TFE3 gene fusions are rare subtypes of renal neoplasm that predominantly occur in younger individuals. There are very few reports describing the cytologic features of these tumors.

METHODS

A 27-year-old man presented with hematuria and was found to have a mass in the lower part of the right kidney. Cytology of catheterized urine obtained from the right renal pelvis showed clusters of cells with abundant clear or eosinophilic granular cytoplasm, large round nuclei and prominent nucleoli. Papillary clusters containing thin fibrous stroma were occasionally seen. Voided urine cytology showed similar cell clusters but degeneration made the features obscure. Nephroureterectomy revealed a renal tumor showing a mixed papillary and nested architecture. The diagnosis was confirmed by immunohistochemistry and fluorescence in situ hybridization.

CONCLUSIONS

The present case indicates that the characteristic features of these tumor subtypes can be retained in urine cytology. Cytology may be enough to suspect these tumors as part of the differential diagnosis when the patient's age and imaging findings are taken into account and may facilitate further studies for a definitive diagnosis.

Thirty-one cases of low-grade renal cell carcinoma (RCC) with clear cells and tubulopapillary/papillary architecture were analyzed retrospectively with immunohistochemical and genetic markers to gain more experience with the differential diagnosis of such cases. All samples coexpressed CK7 and CA9; the TFE3 or TFEB reactions were negative; the CD10 and the AMACR stainings were negative in 27 cases and 30 cases, respectively. The FISH assays for papillary RCC, available in 27 cases, and deletion of chromosome 3p, available in 29 cases, gave negative results. The results for 3p deletion, VHL gene mutation or VHL gene promoter region hypermethylation testing, along with the diffuse CD10-positivity in 2 cases confirmed 21 cases as clear cell papillary RCC (CCPRCC; CK7+, CA9+; no 3p loss, no VHL abnormality) and 10 cases as clear cell RCC (CCRCC; CK7+, CA9+; no 3p loss, VHL abnormality mutation/hypermethylation present). In CCPRCCs, the representative growth pattern was branching tubulo-acinar, commonly accompanied by cyst formation. The linear nuclear arrangement or cup-shaped staining of CA9 did not necessarily indicate CCPRCC, and the absence of these did not exclude the diagnosis of CCPPRC. One tumor infiltrated the renal sinus; the others exhibited pT1 stage; and metastatic outcome was not recorded. The CCRCC cases were in pT1 stage; 6 exhibited cup-shaped staining of CA9, and 1 displayed lymph node metastasis at the time of surgery. Distant metastatic disease was not observed. In summary, the VHL abnormalities distinguished the subset of CCRCC with diffuse CK7-positivity and no 3p loss from cases of CCPRCC.

Xp11.2 translocation/transcription factor E3 (TFE3) gene fusion renal cell carcinoma (Xp11.2 translocation RCC) was first classified as a distinct type of renal tumor by the World Health Organization in 2004. However, its morphology and clinical manifestations often overlap with those of conventional RCCs. Moreover, a micropapillary pattern (MPP) comprising small papillary cell clusters surrounded by lacunar spaces has never been described in RCC. We compared the clinicopathological and prognostic characteristics of one patient with Xp11.2 translocation RCC exhibiting an MPP (TFE3-M) to those of four patients with conventional Xp11.2 translocation RCC (TFE3-N); all five tumors resembled conventional RCCs on gross pathology. All patients exhibited similar histologies, clinical manifestations, and prognoses, and all underwent radical nephrectomy. However, their characteristics differed significantly from those of other MPP-comprising neoplasms. Both tumor types were positive for TFE3 and vimentin; however, TFE3-M tumor cells expressed epithelial membrane antigen and human melanoma black-45 but not cluster of differentiation 10 (CD10), whereas the TFE3-N cells expressed P504S, CD10, and vimentin but not cytokeratin 7. Our RT-PCR analysis result showed that TFE3-N and TFE3-M tumor cells were identified expressing ASPSCR1-TFE3 and PRCC-TFE3 fusion genes, respectively. These findings suggest that TFE3-M should be classified as a histological subtype of Xp11.2 translocation RCC, although its relationship with other MPP-exhibiting neoplasms remains unclear. The histological characteristics of Xp11.2 translocation RCCs depend on MiT family transcription factors and their gene fusion partners. Xp11.2 translocation RCC should be considered for malignancies presenting with a particular pattern; such malignancies can be identified reliably by their morphological and immunohistochemical profiles.

We have systematically retrieved genes with coding mononucleotide repeats from sequence databases and analyzed them for mutations in tumors with high levels of microsatellite instability (MSI-H). We found somatic frameshift mutations in 7/13 genes previously not analyzed in MSI-H tumors. According to the frequency of mutations in MSI-H tumors, these genes could be divided into genes with high coding mononucleotide repeat instability (CMRI-H) and genes with low coding mononucleotide instability (CMRI-L). CMR-H genes were mutated in more than 9/38 and CMRI-L in less than 4/38 of MSI-H tumors. Four genes in our study were CMRI-H and could thus possibly play a role in the development of MSI-H tumors: TFE3 (9/38), TEF4 (12/38), RGS12 (11/38), and TCF1 (12/38). Our results suggest that systematic identification of genes with CMR in the sequence databases and determination of mutation frequency in MSI-H tumors might be a powerful tool for identification of new molecular targets in the development of MSI-H tumors.

Melanotic Xp11 translocation renal cancer is a rare category of MiTF/TFE3 neoplasms morphologically resembling Xp11 translocation renal cell carcinoma, Xp11 translocation perivascular epithelioid cell tumor, and melanoma. The diagnosis requires demonstration of TFE3 gene rearrangement, by either fluorescence in situ hybridization (FISH) at the Xp11.2 locus or by TFE3 immunohistochemistry. As cytology smears can be useful adjuncts in cytogenetic and molecular testing, we demonstrate TFE3 rearrangement by FISH analysis on cytologic smears in melanotic Xp11 translocation renal cancer. An 18-year-old girl presented with a large right renal mass. Intraoperative scrape smears were performed on suspicious aortocaval lymph nodes. A subset of smears was stained (Papanicolaou and DiffQuik). Morphologically, the neoplastic cells exhibited abundant clear vacuolated cytoplasm and moderate to marked nuclear pleomorphism. Unstained and destained smears were examined for TFE3 rearrangement by FISH. Positive TFE3 FISH results on formalin-fixed paraffin-embedded tissue correlated with the positive FISH findings of TFE3 gene rearrangement on cytologic smears. Therefore, the diagnosis of melanotic Xp11 translocation renal cancer was rendered. In Xp11 translocation associated neoplasms, FISH analysis on cytologic smears can be an efficient, accurate, and cost-effective method for evaluating TFE3 rearrangement.

The paper describes a clinical case of the rare tumor renal cell carcinoma associated with Xp11 translocations involving the TFE3 gene in a 53-year-old male patient. It provides the detailed characteristics of current diagnostic techniques.

Transcription factor EB (TFEB), a well-known master regulator of autophagy and lysosomal biogenesis, is a member of the microphthalmia family of transcription factors (MiT family). Over the years, TFEB has been shown to have diverse roles in various physiological processes such as clearance for intracellular pathogenic factors and having developmental functions such as dendritic maturation, as well as osteoclast, and endoderm differentiation. However, in the present study, we propose a novel mechanism for TFEB governing pluripotency of mouse ESCs (mESCs) by regulating the pluripotency transcriptional network (PTN) in these cells. We observed high levels of TFEB mRNA and protein levels in undifferentiated mESCs. Interestingly, we found a reduction of Nanog and Sox2 levels in TFEB knockout (KO) mESCs while pluripotency was maintained as there was an upregulation of TFE3, a potent stem cell maintenance factor. In consistent, double knockout of TFEB/TFE3 (TFEB/3 DKO) reduced mESC pluripotency, as indicated by the loss of ESC morphology, reduction of ESC markers, and the emergence of differentiation markers. We further discovered that Nanog was a TFEB target gene in undifferentiated mESCs. TFEB also promoted sex-determining region Y-box2 (Sox2) transcription by forming a heterodimer with Sox2 in mESCs. Notably, Sox2, Oct4, and Nanog were also binding to the TFEB promoter and thus generating a feed-forward loop in relation to TFEB. Although high levels of nuclear TFEB are expected to enhance autophagy-lysosomal activity, undifferentiated mESC remarkably displayed low basal autophagy-lysosomal activity. Overexpression or knockout of TFEB did not affect the expression of TFEB lysosomal-autophagy target genes and TFEB also had a lesser binding affinity to its own lysosomal promoter-target genes in mESCs compared to differentiated cells. Collectively, these findings define a newly incorporative, moonlighting function for TFEB in regulating PTN, independent of its autophagy-lysosomal biogenesis roles.

Alveolar soft part sarcoma (ASPS) is a rare soft tissue sarcoma characterized by an alveolar or organoid arrangement of polygonal tumour cells separated by fibrovascular septa. A specific fusion gene [ASPS critical region 1 (ASPSCR1)-TFE3] was detected in ASPS. Despite being a slow-growing tumour without pain and dysfunction, ASPS is characterized by early metastasis, which leads to poor prognosis. Herein, we report a rare case of primary ASPS of the cheek harbouring ASPSCR1 (exon 7)-TFE3 (exon 5) fusion gene in a 21 year-old woman. This tumour was a well-circumscribed, smooth, round mass that was clinically suspected as a benign tumour. However, histologically, it was observed that the polygonal tumour cells were arranged in solid and alveolar growth patterns. Post-operative examination of the whole body excluded the possibility of metastasis at other sites. Thus, careful immunohistochemical and genetic analyses, as well as whole-body examination, demonstrated that the tumour was a primary ASPS of the cheek.

Keywords: ASPS; ASPSCR1; Alveolar soft part sarcoma; Cheek tumour; TFE3.

This study was to investigate the features of renal carcinomas associated with Xp11.2 translocations/TFE3 gene fusions (Xp11.2-RCC) on conventional ultrasound (US) and contrast-enhanced ultrasound (CEUS).

US and CEUS features of twenty-two cases with histopathologically proven Xp11.2-RCC were retrospectively reviewed.

22 patients (11 males, 11 females) were included in this study, with a mean age of 28.3 ± 20.4 years. Eight tumors (36.3%, 8/22) were in left kidney, and 14 tumors (63.7%, 14/22) were in right kidney. All tumors (100%, 22/22) were mixed echogenicity type. 13 tumors (59.1%, 13/22) presented small dotted calcifications. The boundary of 14 tumors (63.6%, 14/22) was sharp and the other 8 tumors' (36.4%, 8/22) boundary was blurry. By CEUS, in early phase, the solid element of all tumors showed obvious enhancement. In delayed phase, 13 tumors showed hypoenhancement, seven tumors showed isoenhancement, and 2 tumors showed hyperenhancement. There were irregular nonenhancement areas in all tumors inside.

By US and CEUS, when children and adolescents were found to have hyperechoic mixed tumor in kidney with sharp margin and calcification, and the tumors showed obvious enhancement and hypoenhancement with irregular nonenhancement areas in the tumor in early phase and delayed phase, respectively, Xp11.2-RCC should be suspected.

The Q fever agent Coxiella burnetii is a Gram-negative bacterium that invades macrophages and replicates inside a specialized lysosomal vacuole. The pathogen employs a type 4B secretion system (T4BSS) to deliver effector proteins into the host cell that modify the Coxiella-containing vacuole (CCV) into a replication-permissive niche. Mature CCVs are massive degradative organelles that acquire lysosomal proteins. Inhibition of mammalian (or mechanistic) target of rapamycin complex 1 (mTORC1) kinase by nutrient deprivation promotes autophagy and lysosome fusion, as well as activation of the transcription factors TFE3 and TFEB (TFE3/B), which upregulates expression of lysosomal genes. Here, we report that C. burnetii inhibits mTORC1 as evidenced by impaired localization of mTORC1 to endolysosomal membranes and decreased phosphorylation of elF4E-binding protein 1 (4E-BP1) and S6 kinase 1 in infected cells. Infected cells exhibit increased amounts of autophagy-related proteins protein 1A/1B-light chain 3 (LC3) and p62 as well as of activated TFE3. However, C. burnetii did not accelerate autophagy or block autophagic flux triggered by cell starvation. Activation of autophagy or transcription by TFE3/B increased CCV expansion without enhancing bacterial replication. By contrast, knockdown of tuberous sclerosis complex 1 (TSC1) or TSC2, which hyperactivates mTORC1, impaired CCV expansion and bacterial replication. Together, these data demonstrate that specific inhibition of mTORC1 by C. burnetii, but not amplified cell catabolism via autophagy, is required for optimal pathogen replication. These data reveal a complex interplay between lysosomal function and host cell metabolism that regulates C. burnetii intracellular growth.IMPORTANCECoxiella burnetii is an intracellular pathogenic bacterium that replicates within a lysosomal vacuole. Biogenesis of the Coxiella-containing vacuole (CCV) requires effector proteins delivered into the host cell cytosol by the type 4B secretion system (T4BSS). Modifications to lysosomal physiology required for pathogen replication within the CCV are poorly understood. Mammalian (or mechanistic) target of rapamycin complex 1 (mTORC1) is a master kinase that regulates lysosome structure and function. Nutrient deprivation inhibits mTORC1, which promotes cell catabolism in the form of accelerated autophagy and increased lysosome biosynthesis. Here, we report that C. burnetii growth is enhanced by T4BSS-dependent inhibition of mTORC1 that does not activate autophagy. Canonical inhibition of mTORC1 by starvation or inhibitor treatment that induces autophagic flux does not benefit C. burnetii growth. Furthermore, hyperactivation of mTORC1 impairs bacterial replication. These findings indicate that C. burnetii inhibition of mTORC1 without accelerated autophagy promotes bacterial growth.

Coxiella burnetii is an obligate intracellular bacterial pathogen that replicates inside the lysosome-derived Coxiella-containing vacuole (CCV). To establish this unique niche, C. burnetii requires the Dot/Icm type IV secretion system (T4SS) to translocate a cohort of effector proteins into the host cell that modulate multiple cellular processes. To characterize the host-pathogen interactions that occur during C. burnetii infection, SILAC based proteomics was used to identify changes in the host proteome during infection of a human-derived macrophage cell line. These data revealed that the abundance of many proteins involved in host cell autophagy and lysosome biogenesis were increased in infected cells. Thus, the role of host transcription factors TFEB and TFE3, which regulate the expression of a network of genes involved in autophagy and lysosomal biogenesis, were examined in the context of C. burnetii infection. During infection with C. burnetii, both TFEB and TFE3 were activated as demonstrated by transport of these proteins from the cytoplasm into the nucleus. Nuclear translocation of these transcription factors was shown to be dependent on the T4SS as a Dot/Icm mutant showed reduced nuclear translocation of TFEB and TFE3. This was supported by the observation that blocking bacterial translation with chloramphenicol resulted in the movement of TFEB and TFE3 back into the cytoplasm. Silencing of tfeb and tfe3, alone or in combination, significantly reduced the size of the CCV, which indicates that these host transcription factors facilitate expansion and maintenance of the organelle that supports C. burnetii intracellular replication.

Perivascular epithelioid cell tumors (PEComas) are a group of mesenchymal tumors that coexpress melanocytic and smooth muscle markers; their exact origin remains unknown. This group includes renal angiomyolipoma, clear cell sugar tumor, and lymphangioleiomyomatosis, although the term perivascular epithelioid cell tumors is currently used for lesions that exhibit a similar morphologic and immunohistochemical profile throughout the human body. Recently, a distinct subset of PEComas has been shown to harbor transcription factor E3 gene (TFE3) fusions. We report, for the first time, a unique case of TFE3-positive PEComa presenting as acute appendicitis in a 24-year-old woman. Microscopically, the tumor was composed of benign-appearing epithelioid cells with clear and eosinophilic cytoplasm, and arranged in nested and alveolar patterns. Immunohistochemical studies showed diffuse strong positivity for neuron-specific enolase, TFE3, and progesterone receptor and focal strong positivity for human melanoma black-45 (HMB-45) and melanocyte differentiation antigen (Melan-A) in the tumor cells. Although rare, PEComa should be included in the differential diagnosis of mesenchymal tumors of the appendix.

Generating human organs inside interspecies chimeras might one day produce patient-specific organs for clinical applications, but further advances in identifying human chimera-competent pluripotent stem (PS) cells are needed. Moreover, the potential for human PS cells to contribute to the brains in human-animal chimeras raises ethical questions. The use of non-human primate (NHP) chimera-competent PS cells would allow one to test interspecies organogenesis strategies while also bypassing such ethical concerns. Here, we provide the first evidence for a putative chimera-competent pluripotent state in NHPs. Using histone deacetylase (HDAC) and selective kinase inhibition, we converted the PS cells of an Old World monkey, the African Green monkey (aGM), to an ERK-independent cellular state that can be propagated in culture conditions similar to those that sustain chimera-competency in rodent cells. The obtained stem cell lines indefinitely self-renew in MEK inhibitor-containing culture media lacking serum replacement and FGF. Compared to conventional PS cells, the novel stem cells express elevated levels of KLF4, exhibit more intense nuclear staining for TFE3, and manifest increased mitochondrial membrane depolarization. These data are preliminary but indicate that the key to deriving primate chimera-competent PS cells is to shield cells from the activation of ERK, PKC, and WNT signaling. Because of the similarity of aGMs to humans, the more ethically palatable use of NHP cells, and the more similar gestation length between aGMs and large animals such as sheep, the aGM cell lines described herein will serve as a useful tool for evaluating the efficacy and safety of interspecies organogenesis strategies. Future studies will examine chimera-competency and generalizability to human cells.