Objective: To study the clinicopathologic features, immunophenotype, characteristic FISH pattern and prognosis of renal cell carcinoma (RCC) associated with chromosome X inversion harboring gene fusions involving TFE3. Methods: Ten cases of NONO-TFE3 RCC and four cases of RBM10-TFE3 RCC were investigated at Nanjing Jinling Hospital from 2009 to 2016 by clinicopathological findings, immunohistochemistry, and genetic analysis. Results: Morphologically, the distinct pattern of secretory endometrioid subnuclear vacuolization was overlapped with clear cell papillary RCC, and often accompanied by sheets of epithelial cells in NONO-TFE3 RCC. Most cases of RBM10-TFE3 RCC presented with the biphasic feature that acinar, tubular and papillary patterns of epithelioid cells combined with sheets of small cells with "pseudorosette-like" architectures. In addition, cytoplasmic vacuolization, nuclear groove, and psammoma bodies were also observed. Immunohistochemically, all NONO-TFE3 RCC cases were immunoreactive for TFE3, CD10, RCC markers, and PAX8, and negative for CK7, Cathepsin K, Melan A, HMB45, Ksp-cadherin, vimentin, and CD117. All 4 cases of RBM10-TFE3 RCC showed moderate to strong immunoreactivity for TFE3, Cathepsin K, CD10, Ksp-cadherin, E-cadherin, P504s, RCC marker, PAX8, and vimentin but negative for TFEB, HMB45 and CK7. CKpan and Melan A were at least focally expressed. The antibody to Ki-67 showed labeling of 3%-8% (mean 5%). There were some expression discrepancies of immunochemistry between different histological patterns. PAX8, CKpan, P504s, and Ksp-cadherin were expressed in epithelioid areas but not in small-cell areas. Ki-67 labeling index of epithelioid areas was higher than that in small-cell areas. In molecular analysis, NONO-TFE3 fusion transcripts were identified in 6 patients. The fusion points were between exon 7 of NONO and exon 6 of TFE3 in 5 patients and between exon 9 of NONO and exon 5 of TFE3 in one patient. All 4 cases of RBM10-TFE3 RCC demonstrated to have RBM10-TFE3 fusion transcripts and the fusion points were between exon 5 of TFE3 and exon 17 of RBM10. Using TFE3 break-apart FISH assay, all 10 cases of NONO-TFE3 RCC showed characteristic patterns of equivocal split signals with a distance of nearly 2 signal diameters. All 4 cases of RBM10-TFE3 RCC showed colocalized or subtle split signals with a distance of <1 signal diameter, which was considered as negative results. Long-term follow-up was available for 7 patients of NONO-TFE3 RCC and 4 patients of RBM10-TFE3 RCC. All patients were alive with no evidence of disease. Conclusions: Two rare genotypes, NONO-TFE3 RCC and RBM10-TFE3 RCC, are reported in this study. Both of these two tumors show specific morphology and good prognosis, along with the positive TFE3 staining and the equivocal or false-negative TFE3 FISH results, which could be missed. PCR detection or next-generation sequencing can determine the genotype.

A 35 year old female presented with a painless swelling on the outer aspect of left upper arm for the last one year. On examination, the swelling measured 4.5 x 4 cm. It was soft to firm, ill defined, non-tender, deeply located and was not attached to the overlying skin. A computed tomographic scan revealed a homogenous soft tissue mass measuring 4.5 x 4 cm located within the muscle.

Keywords: Alveolar soft part sarcoma; TFE3; fine needle aspiration cytology.

Epithelioid hemangioendotheliomas (EHE) of the liver are rare, low-malignant vascular tumors whose molecular pathogenesis is incompletely understood. The diagnosis of EHE is challenging, and the course of the disease can be highly variable. Therapeutic options for EHE are limited, including resection of primary and metastatic tumors, organ transplantation and rather ineffective systemic approaches. Driver mutations have been reported (fusion transcripts of either YAP-TFE3 or WWTR1-CAMTA1) but comprehensive molecular profiling has not been performed. Our aim was to molecularly characterize hepatic EHE to identify new molecular targets. Eight primary hepatic EHE were analyzed by next-generation sequencing using a 409-gene panel. The majority of primary hepatic EHE revealed a low number of mutations. Genes that were mutated primarily are involved in DNA repair, epigenetic regulation, signaling pathways and cell cycle control, indicating that EHE present with mutations in various functions. Although only detecting a low mutation rate, a comparison with comprehensive databases (target db V3) revealed mutations in five genes with putative therapeutical options. Therefore, our findings help to shed light on the molecular background of EHE and might pave the way to new therapeutic approaches.

Renal cell carcinoma is the most common malignancy of the kidney in adults. In children, however, it only accounts for an estimated 1.8 to 6.3% of all pediatric malignant renal tumors. Papillary renal cell carcinoma is the second most common type of renal cell carcinoma in children. We present the case of a 12-year-old boy with a 2-month history of abdominal pain, unexplained weight loss, and gross hematuria. Computed tomography revealed a horseshoe kidney and a well-defined mass of 4 cm arising from the lower pole of the right kidney. Microscopically the tumor was composed of papillae covered with cells with abundant eosinophilic cytoplasm and high-grade nuclei with prominent nucleoli. Immunohistochemistry was performed; EMA, Vimentin, and AMACR were strongly positive while CK7, CD10, RCC antigen, TFE3, HMB-45, and WT-1 were negative. Currently, 10 months after the surgical procedure, the patient remains clinically and radiologically disease-free.

Recent molecular discoveries have refined vascular bone tumor classification. To investigate the clinical relevance of these refinements, we reviewed all cases of primary vascular bone tumors treated at our Institute. On the basis of morphology, cases were assessed immunohistochemically and molecularly. A total of 427 cases of primary vascular tumor of bone with available follow-up and histologic material were retrieved and reclassified according to the most recent diagnostic criteria as follows: 289 hemangiomas, 38 epithelioid hemangiomas, 21 epithelioid hemangioendotheliomas, 2 retiform hemangioendotheliomas, 1 intraosseous papillary intralymphatic angioendothelioma, 24 pseudomyogenic hemangioendotheliomas, and 52 angiosarcomas (of these, 45 were epithelioid angiosarcomas and 7 spindle cell secondary angiosarcoma). Both epithelioid and classic hemangiomas behave as benign tumors with excellent prognosis. The distinction between cellular and conventional type of epithelioid hemangioma was not associated with a different clinical course. Conversely, epithelioid hemangioendothelioma exhibited a more aggressive clinical behavior than hemangioma, with higher rates of multifocality and distant spread. Immunohistochemical positivity for CAMTA1 or TFE3 did not have a prognostic implication. In epithelioid hemangioendothelioma, the presence of morphologic malignant features was associated with reduced disease-free (P=0.064) and overall survival (P=0.055). Pseudomyogenic hemangioendothelioma featured local aggressiveness in 5/24 patients exhibiting a clinical behavior closer to epithelioid hemangioma than epithelioid hemangioendothelioma. Last, 32/45 patients with epithelioid angiosarcoma died of disease with a median survival time of 10 months from diagnosis. In conclusion, the integration of morphologic, immunohistochemical, and molecular features allows a better stratification of primary vascular tumors of bone with significant prognostic and therapeutic implications.

Objective: To investigate the clinicopathological features of pulmonary epithelioid hemangioendothelioma (PEHE). Methods: Eighteen cases of PEHE were collected from August 2011 to December 2018 at the First Affiliated Hospital of Zhengzhou University. All cases were retrospectively studied by hematoxylin and eosin staining and immunohistochemistry (IHC). The clinicopathological features were reviewed; the status of CAMTA1 and TFE3 gene was analyzed and patients' outcome was followed up. Results: Of the 18 cases, there were 11 males and 7 females with a male to female ratio of 1.6 to 1.0. The patients' age ranged from 36 to 68 years (mean 52 years). Twelve cases (12/18) showed a single nodule and six cases (6/18) showed multiple bilateral nodules. Seven cases (7/18) involved other organs besides lung. Seventeen (17/18) patients presented with respiratory symptoms and one patient (1/18) presented with abdominal pain. Grossly, the tumors were greyish-white nodules with indistinct borders. Microscopically the tumor cells were epithelioid and arranged in strands and nests, and cytoplasmic vacuoles were commonly noted. The stroma was myxochondroid or hyaline. By IHC, the tumor cells were positive for CD31(18/18), CD34 (16/18), ERG (18/18) and Fli-1 (18/18); CKpan was focally positive in 5 cases (5/18). TFE3 was positive in 3 cases (3/18), and Ki-67 index ranged from 5% to 30%. FISH analysis showed seventeen cases (17/18) had CAMAT1 rearrangement, one case had TFE3 rearrangement displaying a split signal. Eight patients (8/18) had surgical excision, three patients (3/18) had surgery and chemotherapy, and seven patients (7/18) had chemotherapy only. Four patients (4/18) died of the disease. Conclusions: Patients with PEHE have non-specific symptoms, and correct diagnosis depends on pathologic biopsy and the exclusion of other tumors with epithelioid morphology. Some patients with PEHE have poor prognosis, particularly in those who have multiple nodules, peripheral invasion or metastasis.

目的： 探讨肺上皮样血管内皮瘤（pulmonary epithelioid hemangioendothelioma，PEHE）的临床病理特征及预后。 方法： 分析2011年8月至2018年12月郑州大学第一附属医院PEHE 18例，进行常规HE染色，免疫组织化学染色，总结临床病理特征，并随访患者生存情况。用荧光原位杂交（FISH）法对18例进行CAMTA1基因检测，对3例免疫组织化学TFE3阳性病例进行TFE3基因检测。 结果： 18例PEHE中，男11例，女7例，男女比例为1.6∶1.0，年龄36~68岁，平均年龄52岁。12例（12/18）为肺内单发结节，6例（6/18）为双肺多发结节。7例（7/18）有肺外其他器官受累。17例（17/18）患者有呼吸系统症状，1例（1/18）患者表现为腹痛。大体均表现为灰白色结节，界限不清。镜下观察：黏液或者软骨样的基质中见上皮样的细胞排列呈条索状或者小巢状,可见胞质内空泡。免疫组织化学染色显示肿瘤表达CD31（18/18）、CD34（16/18）、ERG（18/18）、Fli-1（18/18），5例（5/18）局灶表达广谱细胞角蛋白，3例（3/18）TFE3阳性，Ki-67阳性指数5%~30%。FISH检测17例（17/18）CAMTA1基因断裂，3例免疫组织化学表达TFE3病例中1例TFE3基因断裂。治疗方法：手术治疗8例，手术辅助化疗3例，单纯化疗7例。15例获得预后资料的患者中4例死亡。 结论： PEHE症状缺乏特异性，确诊有赖于病理学活检，在肺内需和多种肺部肿瘤鉴别。部分患者预后差，肿瘤多发、侵犯周围器官及远处转移可能与预后不良有关。.

Keywords: CAMTA1 gene; Hemangioendothelioma; Lung neoplasms; TFE3 gene.

The present study aimed to investigate the role of transcription factor E3 (TFE3) in the regulation of proliferation in renal adenocarcinoma cells. The LV‑TFE3 overexpression (OE) lentivirus and negative control CON195 (NC) lentivirus were transfected into the ACHN cell line. Protein expression of FLAG‑tag TFE3 was determined using western blot analysis. Differences in cell proliferation, plate clone formation and cell cycle distribution between OE and NC groups were compared using MTT, plate colony formation and flow cytometry assays, respectively. The levels of mammalian target of rapamycin (mTOR) and phosphorylated ribosomal protein S6 (p‑rpS6) were analyzed by western blotting. Cell proliferation and colony formation increased significantly in the OE group compared with the NC group. The % of cells in the G1 and G2 phases of the cell cycle decreased, while the % of cells in the S phase of the cell cycle increased in the OE group compared with the NC group. In addition, mTOR and p‑rpS6 levels were increased in the OE group compared with the NC group. The results of the present study demonstrated that TFE3 overexpression resulted in increased ACHN cell proliferation and plate clone formation. TFE3 may promote renal tumor growth by regulating cell cycle progression and activating the phosphatidylinositol 3‑kinase/AKT serine/threonine kinase 1/mTOR signaling pathway.

Folliculin interacting protein 1 (Fnip1) is a cytoplasmic protein originally discovered through its interaction with the master metabolic sensor 5' AMP-activated protein kinase (AMPK) and Folliculin, a protein mutated in individuals with Birt-Hogg-Dubé Syndrome. In response to low energy, AMPK stimulates catabolic pathways such as autophagy to enhance energy production while inhibiting anabolic pathways regulated by the mechanistic target of rapamycin complex 1 (mTORC1). We previously found that constitutive disruption of Fnip1 in mice resulted in a lack of peripheral B cells because of a block in B cell development at the pre-B cell stage. Both AMPK and mTORC1 were activated in Fnip1-deficient B cell progenitors. In this study, we found inappropriate mTOR localization at the lysosome under nutrient-depleted conditions. Ex vivo lysine or arginine depletion resulted in increased apoptosis. Genetic inhibition of AMPK, inhibition of mTORC1, or restoration of cell viability with a Bcl-x_L transgene failed to rescue B cell development in Fnip1-deficient mice. Fnip1-deficient B cell progenitors exhibited increased nuclear localization of transcription factor binding to IgHM enhancer 3 (TFE3) in developing B cells, which correlated with an increased expression of TFE3-target genes, increased lysosome numbers and function, and increased autophagic flux. These results indicate that Fnip1 modulates autophagy and energy response pathways in part through the regulation of AMPK, mTORC1, and TFE3 in B cell progenitors.

Perivascular epithelioid cell neoplasms (PEComas) are a family of mesenchymal neoplasms with features of both melanotic and smooth muscle differentiation. PEComa morphology is highly variable and encompasses epithelioid to spindle cells often with clear cytoplasm and prominent nucleoli. Molecularly, most PEComas are defined by a loss of function of the TSC1/TSC2 complex. Additionally, a distinct small subset of PEComas harboring rearrangements of the TFE3 (Xp11) gene locus has been identified. By presenting a series of three case reports with distinct features, we demonstrate diagnostic pitfalls as well as the importance of molecular work-up of PEComas because of important therapeutic consequences.

Papillary renal cell carcinoma (PRCC) is currently a well-studied type of RCC. In addition to PRCC type 1, there are a number of other subtypes and variants of PRCCs which have been reported. We describe a series of 6 PRCCs with papillary, micropapillary and/or tubulopapillary architecture and prominent spindle cell stroma, resembling stroma in mixed epithelial and stromal tumor of the kidney (MESTK) or sarcomatoid RCC. Clinicopathologic, morphologic, immunohistochemical and molecular features were analyzed. All patients were males with an age range of 44-98 years (mean 65.3, median 65.5 years). Tumor size ranged from 2.4-11.4 cm (mean 5.8, median 4.5 cm). Follow-up data were available for 4 patients, ranging from 3 to 96 months (mean 42.75, median 36 months). Epithelial cells were mostly cylindrical with eosinophilic cytoplasm, showing nuclear grade 2 and 3 (ISUP/WHO). In all cases, loose to compact prominent stroma composed of spindle cells, without malignant mesenchymal heterologous elements was detected. No atypical mitoses were found, while typical mitoses were rare in both epithelial and stromal components. Epithelial cells were positive for CK7, AMACR, and vimentin in all cases, while negative for TFE3, HMB45, desmin, CD34, and actin. The stroma was positive for vimentin, actin and focally for CD34, while negative for CK7, AMACR, TFE3, HMB45, and desmin. Estrogen and progesterone receptors were completely negative. FH and SDHB expression was retained in all analyzable cases. Proliferative index was barely detectable in stromal component and low in epithelial component, ranging 0 to 5% positive stained cells/high power field. Copy number variation was variable with no distinct pattern. No mutations in CDKN2A, BAP1, MET were detected. PRCC with MESTK-like features is a distinct variant of PRCC mimicking MESTK. Our findings add to the body of literature on ever expanding variants of PRCCs. Both epithelial and stromal components lacked true Müllerian features, which was also proven by immunohistochemistry.

Renal cell carcinomas (RCC) are divided in several subtypes, characterized by morphological and histological features, protein expression patterns and genetics criteria. The main subtypes include Clear cell renal cell carcinoma (CCRCC), Papillary RCC (PRCC), Chromophobe RCC (ChRCC), oncocytoma, TFE3 and TFEB Translocation renal cell carcinoma (TRCC). In most cases, RCC can be easily classified according to histological criteria and immunohistochemistry. Nevertheless, the subtyping process can be more complex in some cases: differential diagnosis (CCRCC or TFE3 TRCC, PRCC or TFE3 TRCC, oncocytic tumors corresponding to ChRCC or oncocytoma), molecular confirmation (TFEB TRCC) and unclassified RCC. Complementary analyses are required such as fluorescence in situ hybridization (FISH) for the detection of chromosomal abnormalities associated to each subtype. In this aim, this study assessed the performance of FISH analysis in the histological classification of 359 RCC exhibiting unusual histological characteristics and/or occurring in young people. FISH probes were selected according to the histological features of each tumor. FISH analysis contributed to the histological classification in 73% of the RCC (261/359). Conversely, FISH did not contribute to the diagnosis in 19% of the cases (69/359) and a hybridization failure was observed for the remaining tumors (8%; 29/359). Considering the different RCC subtypes, FISH analysis was highly efficient to confirm the histological diagnosis of CCRCC, PRCC, and TFE3 TRCC and to identify abnormalities of the TFEB gene. However, this strategy showed some limitations for the diagnosis of oncocytic tumors and unclassified RCC, suggesting that additional molecular assays should be evaluated in these cases.

Xp11 translocation renal cell carcinoma (TRCC) is a rare subtype of renal cell carcinoma characterized by chromosomal translocations involving the TFE3 gene located at the Xp11.2 locus. Initial cases were more common in children, but cases in older adults have begun to accrue and suggest a relatively more aggressive course. We report a case of Xp11 TRCC in a 63-year-old female patient with initial presentation mimicking upper urinary tract urothelial cell carcinoma, with biopsy proving TRCC. She underwent a radical nephrectomy and paracaval lymph node dissection and is followed up with the intent to initiate vascular endothelial growth factor-targeted therapy in case of recurrence.

OBJECTIVE

To study the clinicopathologic features, differential diagnosis and prognosis of renal cell carcinoma associated with Xp11.2 translocations/TFE3 gene fusions.

METHODS

The histopathologic findings and immunophenotype of 11 cases of renal cell carcinoma associated with Xp11.2 translocations/TFE3 gene fusions were studied. Follow-up data (ranged from 10 to 112 months) were also analyzed.

RESULTS

There were a total of 7 females and 4 males. The age of patients ranged from 8 to 26 years (mean = 16.3 years). The diameter of the tumors varied from 2.5 to 6.0 cm. Histologically, two morphologic patterns were seen. The first pattern consisted of alveolar, papillary or nested architecture. The tumor cells contained voluminous, clear to eosinophilic cytoplasm, distinct cell borders, vesicular chromatin, and prominent nucleoli. Psammoma bodies were frequently found and could be abundant. In contrast, the second pattern was composed of nested and compact architecture. The tumor cells possessed less abundant cytoplasm and inconspicuous nucleoli. Few psammoma bodies were detected. Immunohistochemical study showed that all cases strongly expressed TFE3, CD10 and P504s. Variable positivity for pan-cytokeratin, epithelial membrane antigen and vimentin was also noted. None of them expressed CK7, Ksp-cadherin and CD117.

CONCLUSIONS

Renal cell carcinoma associated with Xp11.2 translocations/TFE3 gene fusions is a newly described but rarely encountered subtype of renal cell carcinoma. Pathologic diagnosis can be established when taken age of the patients, histopathologic findings and immunoreactivity for TFE3 protein into consideration.

Renal carcinomas associated with translocation of transcription factors of the MiT/TFE family include, according to the latest World Health Organization classification, carcinomas with Xp11 translocation that involve the TFE3 gene and those with translocation t(6;11)(p21;q12) that affect the TFEB gene. Each one of these sub-types have well-defined clinicopathological and molecular characteristics. Currently, progress in molecular techniques has led to the description of neoplasms with molecular changes in these same genes but with alterations different to translocation. Thus, recently, cases have been published of TFEB-amplified renal carcinomas with prognoses that vary from cases associated with translocation and could therefore represent a new entity. We present a case of TFEB-amplified renal carcinoma with a full description of the clinicopathological characteristics and an updated revision of these neoplasms.

BACKGROUND

Xp11.2 translocation renal cell carcinomas (TRCCs) are rare tumors recently accepted as a separated tumor type in 2004 WHO classification. To diagnose these tumors, histological recognition and confirmation of translocation are necessary. While the incidence of overall renal cell carcinomas (RCCs) is increased after the age of 40, Xp11.2 TRCCs are predominantly reported in young patients. The incidence of these tumors in Thailand has not been evaluated.

OBJECTIVE

To identify the frequency of Xp11.2 TRCCs, clinical presentation and follow-up information in 40 year-old or younger patients by using TFE3 immunostaining to confirm the translocation.

METHODS

All cases of 0- to 40-years-old patients diagnosed as RCCs from nephrectomy specimens between 2001 and 2011 at Siriraj Hospital were reviewed by one pathology resident and two pathologists. Immunohistochemical staining for TFE3 was performed on cases morphologically suspected for TRCC or showing unusual histology.

RESULTS

Four cases consistent with Xp11.2 TRCC were identified by TFE3 immunostaining from all 31 cases (12.9%). Three cases were females and one was male. Two cases were at stage 4 and passed away several months after the operation. The other two patients were at stage 2. One patient is alive without recurrence for at least 36 months after surgery alone. The other died from underlying SLE.

CONCLUSIONS

TFE3 immunostaining is a useful andpractical toolfor screening and diagnosis of Xp11.2 TRCCs, but staining results can be difficult to interpret. Thus, genetic analysis is still necessary especially when immunostaining shows problematic result. Fresh tumor tissue sampling in all young patients is recommended in case of further genetic studies needed.

Pediatric RCC is a rare pediatric neoplasm and is distinctly different compared to adult RCC, often demonstrating translocation morphology evidenced by unique histopathological features and TFE3 or TFEB nuclear expression. We report three cases of pediatric TFE3 positive RCC (TFE3-RCC) occurring in the setting of chronic kidney disease and long-term pharmacological immunosuppression, including two cases that developed in the native kidney following kidney transplantation. Together, these cases suggest that the kidney microenvironment in combination with immune dysregulation is likely contributing factors in the pathogenesis of some pediatric RCC, warranting further study. Long-term post-transplant surveillance may warrant screening for RCC.