An orbital perivascular epithelioid cell tumor (PEComa) in a 9-year-old boy: Case report and review of the literature.

Perivascular epithelioid cell tumors (PEComas) are a family of benign neoplasms characterized by smooth muscle and melanocytic differentiation. Orbital cases are rare. A 9-year-old male presented with a slowly growing orbital mass. Magnetic resonance imaging (MRI) revealed a well-defined orbital mass without intracranial extension. The microscopic appearance of the complete resection specimen showed large nests of epithelioid cells with wide cytoplasm containing melanin pigment and round to oval nuclei with mild cytonuclear atypia and low mitotic activity. Immunohistochemistry was positive for HMB45 and negative for melanA, smooth muscle actin, desmin and S-100 protein. Pangenomic RNA-sequencing identified an in-frame NONO-TFE3 rearrangement, and clustering data showed that the tumor's gene expression profile was grouped with other previously studied PEComas. A diagnosis of orbital pigmented PEComa with uncertain malignant potential associated with a NONO-TFE3 rearrangement was made. There was no recurrence after 1 year of follow-up.

The Transition From Localized to Metastatic: A Case Report of Adult TFE3-Positive Xp11.2 Translocation Renal Cell Carcinoma.

Xp11.2 translocation renal cell carcinoma (Xp11.2 RCC) is a rare tumor, occurring more frequently in childhood than in adulthood. It results from Xp11.2 chromosome translocations and the fusion of the transcription factor E3 (TFE3) gene. In this context, we present a case report of an 18-year-old female who was diagnosed with Xp11.2 RCC following open radical nephrectomy and lymph node dissection on the left side. The histopathological analysis indicated stage T3aN1Mx disease, which was confirmed through immunohistochemistry (IHC) and fluorescent in situ hybridization (FISH). The patient remained under observation until March 2023 when systemic scans uncovered the presence of ascites, peritoneal carcinomatosis, and left supraclavicular lymphadenopathy. A subsequent biopsy reaffirmed the primary disease, leading to the planning of systemic treatment involving tyrosine kinase inhibitors (TKIs) and immunotherapy. However, due to financial constraints, the patient's treatment options were limited to sunitinib initially. The current plan involves reevaluation after three months using scans to determine the subsequent course of treatment. Our case report offers crucial insights into the clinical presentation, diagnosis, and treatment of this rare malignancy. This enhances medical understanding, guides research, and improves the management of similar cases. Case reports like this share practical experiences, shaping future studies and patient care.

Transcription factor E3 renal cell carcinoma presenting as secondary hypertension.

Microphthalmia-associated transcription factor family (transcription factor E3 or transcription factor EB) translocation renal cell carcinomas (RCCs) are rare neoplasms. These renal neoplasms can be either asymptomatic and incidentally discovered on imaging or symptomatic, with the most common presenting symptoms being hematuria, pain, and abdominal mass, or paraneoplastic event. In conventional RCCs, hypertension is considered a risk factor and a possible paraneoplastic event, whereas, in translocation RCCs, prior exposure to cytotoxic chemotherapy is the only known risk factor, and hypertension as an isolated associated paraneoplastic event has never been reported. Interestingly, hypertension as the only presenting symptom in RCC is extremely rare. We report a case of transcription factor E3 positive RCC in a young adult presenting only with hypertension that normalized after radical nephrectomy. To the best of our knowledge, this is the first reported case of hypertension secondary to microphthalmia-associated transcription translocation RCC.

Cystic MED15::TFE3 translocation renal cell carcinoma: histologic mimicker of multilocular cystic renal neoplasm of low malignant potential with review of the literature.

Presented are four cystic renal masses which harbored a MED15::TFE3 gene fusion detected by RNAseq, mimicking multilocular cystic neoplasm of low malignant potential. Clinicopathologic and outcomes data were collected for all cases. Radiologically, three cases were diagnosed as complex cystic masses and one case as a renal cyst, three years prior to surgery. The tumors ranged in size from 1.8 to 14.5 cm. Grossly, all masses were extensively cystic. Microscopically, cells with a clear or minimally granular cytoplasm and nuclei with inconspicuous nucleoli lined the cysts' septa. Focally, small mass-forming aggregates of malignant cells were present between septae and were associated with psammomatous calcifications. In case one, apparent prior cyst wall rupture was associated with reactive changes and cystic spaces filled with fibrin clots. Two of the tumors were staged as T1a, one as T1b, and the other as T2b. By immunohistochemistry, the tumors were positive for TFE3, MelanA, and P504S, with apical CD10 while CAIX and CK7 were negative. RNA sequencing was performed on all cases revealing a MED15::TFE3 gene fusion. The patients were alive and without evidence of disease 11-49 months (mean 29.5) after partial nephrectomy. To date, 12 of the 15 MED15::TFE3 fusion renal cell carcinomas published in the literature are cystic, with three being extensively cystic. Thus, if a multilocular cystic renal neoplasm is encountered in a kidney specimen, translocation renal cell carcinoma should be included in the differential diagnosis as cystic MED15::TFE3 tRCCs carry an uncertain prognosis making recognition for future characterization necessary.

p53 aberration and TFE3 gene amplification may be predictors of adverse prognosis in epithelioid angiomyolipoma of the kidney.

BACKGROUND: Although epithelioid angiomyolipoma of the kidney has been studied by several groups, the reported prevalence of malignant behavior remains uncertain and there are not yet definitive predictive biomarkers. We evaluated the behavior of renal epithelioid angiomyolipoma in a consecutive series in a single institution and investigated the prognostic value of aberrant p53 expression and TFE3 gene abnormality. METHODS: We retrospectively reviewed 14 epithelioid angiomyolipomas, most with pure or close to pure epithelioid components, comprising 12 consecutive cases who had attended our institution and two consultation cases. Fluorescence in situ hybridization with TFE3 break-apart probe was performed on 14 cases. The 14 cases were also labeled for p53 and TFE3 by immunohistochemistry. All cases were followed up. RESULTS: Three of the epithelioid angiomyolipomas were strongly positive for TFE3 and two had a mutant expression of p53. Although no TFE3 gene rearrangement was found, the two tumors with strong TFE3 expression showed TFE3 gene amplification. Follow-up details were available for seven of the 12 consecutive cases: two of them had developed metastases and died (29%), their mean overall survival was 41 months, and both had mutant p53 expression. The two consultation cases with TFE3 gene amplification developed recurrence/metastasis within 1 year after surgery. CONCLUSIONS: Our series study from a single institution presented the prevalence of malignant behavior in pure epithelioid angiomyolipomas, although the small number of cases with follow-up data greatly reduced the accuracy. p53 may be a prognostic marker for epithelioid angiomyolipoma. Cases with TFE3 gene amplification had poor prognoses.

Expression of TFE3 in Cellular and Myxoid Type of Neurothekeoma: Four Cases in Young Children and Adolescents.

Introduction: Cellular neurothekeoma is a benign tumor that mainly occurs in young children and adolescents. The aberrant expression of transcription factor E3 (TFE3) has not been reported in cellular neurothekeoma previously. Case report: We report four cellular neurothekeoma with aberrant immunohistochemical expression of TFE3 protein. The fluorescence in situ hybridization (FISH) showed no TFE3 gene rearrangement or amplification. Discussion/Conclusion: TEF3 protein expression may not be related to TFE3 gene translocation in cellular neurothekeoma. TFE3 may be a potential pitfall in diagnosis, for several malignant tumors in children also express TFE3. The aberrant expression of TFE3 may offer insights into cellular neurothekeoma etiology, and associated molecular mechanisms.

Clinical features of TFE3-rearranged renal cell carcinoma / 中华泌尿外科杂志

Objective:A single-center analysis was performed to assess the significant clinical features and prognostic factors of TFE3-rearranged renal cell carcinoma (TFE3 rRCC).Methods:The clinical data of 85 confirmed cases of TFE3 rRCC patients at the Nanjing Drum Tower Hospital, Affiliated Hospital of Medical School, Nanjing University from January 2007 to February 2023 were analyzed retrospectively. Among these patients, there were 39 males and 46 females, with a median age of 32 (26, 45) years. All patients underwent preoperative CT scans, 21/85 cases (24.7%) of TFE3 rRCC exhibited the characteristic feature of "circular calcification" with plain CT imaging, and enhanced CT scan showed that the tumor enhancement during the arterial phase was lower than the adjacent renal cortex. Among the 85 patients in this cohort, the median tumor diameter was 4.8(3.2, 6.5). Thirty-two patients underwent partial nephrectomy (NSS), while 51 patients underwent radical nephrectomy (RN). Two patients with distant metastasis at the time of diagnosis received only sunitinib therapy. Forty-three patients received adjuvant treatment, including 14 patients who received targeted therapy. There were 29 patients in AJCC stage Ⅲ/Ⅳ, with 10 patients presenting with venous tumor thrombus and 14 patients with lymph node metastasis. Histopathology, TFE3 immunohistochemistry, and break-apart TFE3 FISH probe detection were performed on all 85 cases, while 52 patients underwent RT-PCR and/or DNA sequencing. By combining the clinical and pathological data, we summarized the diagnostic Methods for TFE3 rRCC, evaluated the impact of surgical approaches (RN and NSS) on the survival outcomes of cT 1a/b patients, and assessed the influence of genetic subtypes (ASPL, NONO, PRCC, SFPQ, and others) on the survival outcomes of all patients. Furthermore, we analyzed the risk factors for disease progression. Results:TFE3 rRCC exhibited variable histopathological features, and the presence of acinar-like structures with psammoma bodies may be a relatively typical characteristic. All 85 patients showed positive TFE3 immunohistochemical staining. In 6 cases of TFE3 rRCC, break-apart TFE3 FISH probe yielded negative results. However, final confirmation was achieved through genetic sequence, with 5 cases diagnosed as NONO-TFE3 subtype and 1 case as RBM10-TFE3 subtype. Among the 85 patients, 52 underwent RT-PCR and/or DNA sequencing, revealing a total of 8 TFE3 fusion subtypes, including 11 cases of ASPL-TFE3, 8 cases of PRCC-TFE3, 10 cases of NONO-TFE3, 15 cases of SFPQ-TFE3, 1 case of CLTC-TFE3, 2 cases of LUC7L3-TFE3, 4 cases of MED15-TFE3, and 1 case of RBM10-TFE3. The survival analysis results revealed that among the 12 patients with cT 1b stage tumors who underwent radical nephrectomy (RN), the progression-free survival (PFS) was 35 (14, 109) months, which was significantly better than the NSS group ( P=0.041). However, for the 14 patients with cT 1a stage tumors who underwent RN, there was no statistically significant difference in overall survival (OS) and PFS compared to the NSS group, with OS being 55(27, 134) months and PFS being 71(41, 134) months. Stratifying according to TFE3 fusion subtypes, it was found that patients with ASPL-TFE3 fusion had a significantly lower PFS compared to those with non-ASPL-TFE3 fusion subtypes ( P=0.029). Survival analysis revealed that tumor diameter, surgical approach, adjuvant therapy, AJCC staging, venous tumor thrombus, and lymph node metastasis were associated with OS and PFS( P<0.05). The results of the multivariate Cox regression analysis showed that AJCC stage Ⅲ/Ⅳ( HR=2.393, 95% CI 1.418-4.039, P=0.001) and venous tumor thrombus ( HR=3.543, 95% CI 1.159-10.827, P=0.026) were independent risk factors for progression-free survival (PFS). Conclusions:During the non-enhanced phase of CT scan, TFE3 rRCC tumors can exhibit a circular calcification. TFE3 immunohistochemistry is an important screening method for TFE3 rRCC.Break-apart TFE3 FISH probe detection is considered the diagnostic gold standard, and gene sequencing, if feasible, can provide the subtype diagnosis of TFE3 rRCC. For cT 1a stage TFE3 rRCC, partial nephrectomy (NSS) is a viable option, while caution should be taken in selecting NSS for cT1b stage patients. Patients with ASPL-TFE3 fusion subtype have a worse prognosis. AJCC stage Ⅲ/Ⅳ and venous tumor thrombus indicate poor prognosis in TFE3 rRCC.

Clinicopathologic, treatment and prognosis study of 46 Xp11.2 translocation/TFE3 gene fusion renal cell carcinomas.

PURPOSE: To report the clinicopathological features and mid- to long-term oncologic results of Xp11.2 translocation/transcription factor E3 (TFE3) gene fusion renal cell carcinomas (Xp11.2 translocation RCCs) in a single large-volume centrecentre. METHODS: Clinical and follow-up data of 46 patients who were diagnosed with Xp11.2 translocation RCC and underwentunderwent surgical intervention were retrospectively reviewed. RESULT: Forty-six Xp11.2 translocation RCC patients were identified from 4218 renal tumour patients who were underwentunderwent surgery in our centrecentre from Jan. 2014 to Apr. 2020. The incidence of Xp11.2 translocation RCCs in our centre was 1.09%. During a median follow-up period of 30.5 months, 4 patients died of the disease. The total median overall survival and cancer specific survival were 30.0 months and 24.0 months, respectively. The 1-year, 3-year and 5-year OS rates were 97.4%, 88.8%, and 88.8%, respectively. In multivariable analysis, displaying symptoms when diagnosed (p = 0.019), lymph node metastasis (p = 0.002) and distal metastasis (p = 0.020) were identified as risk factors for poor prognosis. CONCLUSION: Xp11.2 translocation RCC is a type of renal cell carcinoma with a relatively low incidence and various prognoses. Early-stage Xp11.2 translocation RCCs have a similar prognosis to most typical RCCs, but late-stage Xp11.2 translocation RCCs can lead to poor oncological outcomes.

Renal cancer associated with Xp11.2 translocation/TFE3 gene fusion: Clinicopathological analysis of 13 cases.

OBJECTIVE: To explore the clinicopathological characteristics, immunohistochemical phenotype, diagnosis and differential diagnosis of renal cell carcinoma associated with Xp11.2 translocation/TFE3 gene fusion. METHODS: The clinical history, pathological morphology, immunohistochemical phenotype and related molecular test results of 13 cases of Xp11.2 translocation/TFE3 gene fusion-related renal cell carcinoma were retrospectively analyzed, and the relevant literature was reviewed. RESULTS: Of the 13 patients, 5 were males and 8 were females. The age of onset ranges from 8 to 73 years old, most of which were middle-aged and elderly patients. Among them, there were 3 cases of left kidney tumor and 10 cases of right kidney tumor. In the treatment method, 2 of the 13 patients underwent partial nephrectomy, and 11 underwent radical nephrectomy. Histopathological morphology showed papillary, nested, tubular and acinar structures. The cytoplasm was transparent or eosinophilic, and the interstitial fibrosis was accompanied by chronic inflammatory cell infiltration, hemosiderin deposition and foam cell aggregation. The immunohistochemical analysis of 13 patient specimens all expressed TFE3 antibody, and the expression intensity was strongly positive; gene FISH detection technology revealed the breakage and rearrangement of TFE3 gene in 12 assessable cases. One of thirteen patients had a metastasis at follow-up from 3 to 69 months. CONCLUSIONS: This type of kidney cancer was a rare subtype. Because of its complex and changeable shape, it has a high degree of overlap with other kidney cancer subtypes, and the missed diagnosis rate and misdiagnosis rate are extremely high. The diagnosis is mainly based on pathomorphology and immunohistochemistry, TFE3 positive expression and TFE3 gene destruction and rearrangement.

Retroperitoneal Sclerosing Angiomyolipoma with Long-Term Follow up: A Case Report with Unique Clinicopathologic and Genomic Profile.

Sclerosing angiomyolipoma (sAML) is a rare variant of the perivascular epithelioid tumors exhibiting distinct morphology with extensive stromal hyalinization, which makes it challenging to recognize. It often lacks an adipose tissue component and melanocytic markers may be expressed only focally, further posing a diagnostic challenge. Here, we report a case of sAML of the left pararenal retroperitoneum in a 52-year-old woman with 92 months of clinical follow up and discuss the histologic features, immunoprofile, molecular alterations, and differential diagnoses that can aid in the diagnosis of this unique and rare entity.

A YAP1::TFE3 cutaneous low-grade fibromyxoid neoplasm: A novel entity!

Cutaneous fibromyxoid neoplasms (CFMN) comprise a vast category of benign and malignant tumors that include, but are not limited to, low-grade fibromyxoid sarcoma, myxofibrosarcoma, myxoid dermatofibrosarcoma protuberans, myxoid solitary fibrous tumor, and myxoid neurofibroma with differing implications for treatment and prognosis. Herein, a case of CFMN arising as a painless, slow-growing, flesh-colored forearm mass in a 53-year-old female is presented. The neoplasm comprised of copious myxoid material with banal spindle cells, exhibiting mild hyperchromasia, dissecting the dermal collagen table. Focal perivascular accentuation of spindle cells was identified in the absence of vasoformative features. Immunohistochemically, lesional cells were strongly and diffusely positive for CD34 and multifocally for Factor XIIIa and epithelial membrane antigen while negative for CD31, ERG, FLI-1, D2-40, smooth muscle actin, Desmin, S100, HMB-45, STAT6, MUC4, and keratins. RNA- and DNA-sequencing identified a YAP1::TFE3 fusion transcript that were subsequently corroborated by fluorescence in situ hybridization and immunohistochemistry for TFE3 (Xp11.23) locus rearrangement and strong, diffuse TFE3 immunoreactivity, respectively. To date, the YAP1::TFE3 fusion has only been identified in a subset of epithelioid hemangioendotheliomas and clear cell stromal tumors of the lung. This is the first report of a CFMN featuring a YAP1::TFE3 fusion (YAP1 Exon 1 and TFE3 Exon 4). The morphologic findings are unlike those previously described for epithelioid hemangioendothelioma and suggest that this neoplasm may represent a yet unclassified or novel CFMN entity. Although the patient is 1-year status postsurgical excision with no evidence of clinical recurrence, the clinical behavior of this novel entity remains to be fully characterized.

Imaging features of renal cell carcinoma associated with Xp11.2 translocation/TFE3 gene fusions: comparison with chromophobe renal cell carcinoma / 中华放射学杂志

Objective:To compare the imaging features of renal cell carcinoma (RCC) associated with Xp11.2 translocation/TFE3 gene fusion (Xp11.2 RCC) with chromophobe RCC.Methods:From November 2016 to January 2020, 28 patients with Xp11.2 RCC and 28 patients with chromophobe RCC confirmed by pathology were retrospectively analyzed in Peking University First Hospital. All 23 patients underwent preoperative CT examination, and 5 patients underwent routine MRI in each group. The clinical and imaging features were observed and recorded. The CT features including side, location, size, boundary, shape, uniform density, composition (solid, cystic-solid, cystic), hemorrhage, calcification, lymph node metastasis of the lesions and distant metastasis were observed, and the CT value of the solid part of the tumor at each stage was measured. On MRI images, the signal of the lesion in each sequence and enhancement mode were observed. The differences in clinical and imaging characteristics between the 2 groups were compared using independent samples t test or χ 2 test. Results:The Xp11.2 RCC more frequently affected young [(27±10) years] patients, while chromophobe RCC more frequently involved middle-aged [(37±7) years] patients asymptomatically, and the difference was statistically significant ( t=-4.99, P<0.001). The lesion size of Xp11.2 RCC [(5.4±2.2) cm] were significantly smaller than that of chromophobe RCC [(6.9±1.8) cm] ( t=-2.93, P=0.005). There were significant differences in the density and composition of lesions between Xp11.2 RCC and chromophobe RCC (χ 2=4.60, 18.67, P=0.032,<0.001). There were no significant differences in the side, location, boundary, shape, hemorrhage, calcification, fat, lymph node metastasis and distant metastasis between the 2 kind of lesions (all P>0.05). The CT values of solid components in Xp11.2 RCC in cortico-medullary phase and delayed phase were higher than those in chromophobe RCC, and the difference were statistically significant ( t=11.80, 20.15, both P<0.001). Five cases of Xp11.2 RCC showed iso- or slightly hyperintense signal on T 1WI and slightly hypointense signal on T 2WI. Two cases showed delayed enhancement after enhancement, and 3 cases showed a slight decrease in delayed phase enhancement. Conclusion:Compared with chromophobe RCC, Xp11.2 RCC has certain characteristics in imaging manifestations (lesion size, density uniformity, composition, CT value of post-enhanced cortico-medullary phase and delayed phase). Imaging manifestations combining the clinical manifestations (age of onset) are helpful for preoperative diagnosis of Xp11.2 RCC.

Is immunohistochemistry always the panacea to morphologic mimics? Two, distinct soft tissue tumors exhibiting alveolar pattern and TFE3 immunoreactivity.

Alveolar soft part sarcoma (ASPS) and certain perivascular epithelioid cell neoplasms (PEComas) exhibit overlapping histopathological features, including immunohistochemical expression of TFE3, as well as TFE3 gene rearrangement. PEComas with an epithelioid morphology are known to exhibit variable immunoexpression of muscle markers. At the same time, aberrant immunoreactivity of HMB45 immunostain, which is invariably, used to substantiate a diagnosis of a PEComa, has been reported in various other tumors. Herein, we discuss two rare cases of soft tissue tumors with overlapping morphological and immunohistochemical features. Case1: A 34-year-old male underwent a biopsy for a recurrent, right-sided nasal polyp. Biopsy showed polygonal tumor cells, containing prominent nucleoli, arranged in a "nesting-type"/alveolar growth pattern. Immunohistochemically, tumor cells displayed TFE3 positivity and an aberrant positivity for HMB45. Special stain (PAS-diastase) highlighted intracytoplasmic granules and crystals. Diagnosis of ASPS was offered. Furthermore, the tumor cells displayed TFE3 gene rearrangement. Case 2: A 29-year-old female underwent an aural polypectomy. Microscopic examination revealed a tumor with a "nesting-type"/alveolar arrangement of tumor cells with vacuolated cytoplasm, arranged around thin-walled blood vessels. Immunohistochemically, tumor cells were diffusely positive for HMB45 and TFE3 and focally for SMA. A diagnosis of a PEComa was offered. This report constitutes the first documentation of aberrant HMB45 immunoreactivity in case of ASPS, and one of the first reported cases of a PEComa in the ear. It emphasizes the value of integrating clinicopathological features with immunohistochemical and molecular results in differentiating two rare, but distinct soft tissue tumors with overlapping features. An exact diagnosis of both these tumor entities has therapeutic implications.

Clinicopathological analysis of children with Xp11.2 translocation/ TFE3 gene fusion associated renal cell carcinoma / 中华实用儿科临床杂志

Objective:To summary the problems that may be encountered in the diagnosis of Xp11.2 translocation/TFE3 gene fusion associated renal cell carcinomas (Xp11 RCC) and to improve the understanding and diagnostic level.Methods:The clinical and pathological data of 5 children with Xp11 RCC pathologically diagnosed in Children′s Hospital of Capital Institute of Pediatrics from January 2015 to December 2019 were collected for retrospective analysis.Results:The 5 cases included 2 males and 3 females with the age of 4-8 years old.All cases presented with abdominal mass.Four cases received radical nephrectomy and radical tumor resection, and 1 case received simple tumor resection after related examination.Routine HE staining, immunohistochemical staining and fluorescence in situ hybridi-zation (FISH) were performed after surgery.The histological morphology of tumor was varied, and the tumor cells were arranged in nest flake, acinar or papillary pattern, with abundant cytoplasm form completely transparent to eosinophilic staining (pink), and gravel-like calcification was visible.Micropapillary arranged tumor cells appeared in 1 case besides classic pattern; in another case, the tumor cells were highly eosinophilic with abundant cytoplasm and visible round or elliptic eosinophilic bodies.The tumor cells in 5 cases showed diffuse and strong expression of TFE3, and FISH assay showed abnormal separation signal.Conclusions:Xp11 RCC is a relatively rare renal malignant tumor with diverse histological morphology, which should be distinguished from other common renal tumors in children.Its immunohistochemical expression and molecular detection are of specificity, and it should be diagnosed based on clinical incidence.

[Clinicopathological features of pulmonary epithelioid hemangioendothelioma: a study of 18 cases].

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.

Clinicopathological Findings on 28 Cases with XP11.2 Renal Cell Carcinoma.

Xp11.2 translocation carcinoma is a distinct subtype of renal cell carcinoma characterized by translocations involving the TFE3 gene. Our study included the morphological, immunohistochemical and clinicopathological examination of 28 Xp11.2 RCCs. The immunophenotype has been assessed by using CA9, CK7, CD10, AMACR, MelanA, HMB45, Cathepsin K and TFE3 immunostainings. The diagnosis was confirmed by TFE3 break-apart FISH in 25 cases. The ages of 13 male and 15 female patients, without underlying renal disease or having undergone chemotherapy ranged from 8 to 72. The mean size of the tumors was 78.5 mm. Forty-three percent of patients were diagnosed in the pT3/pT4 stage with distant metastasis in 6 cases. Histological appearance was branching-papillary composed of clear cells with voluminous cytoplasm in 13 and variable in 15 cases, including one tumor with anaplastic carcinoma and another with rhabdoid morphology. Three tumors were labeled with CA9, while CK7 was negative in all cases. Diffuse CD10 reaction was observed in 17 tumors and diffuse AMACR positivity was described in 14 tumors. The expression of melanocytic markers and Cathepsin K were seen only in 7 and 6 cases, respectively. TFE3 immunohistochemistry displayed a positive reaction in 26/28 samples. TFE3 rearrangement was detected in all the analyzed cases (25/25), including one with the loss of the entire labeled break-point region. The follow-up time ranged from 2 to 300 months, with 7 cancer-related deaths. In summary, Xp11.2 carcinoma is an uncommon form of renal cell carcinoma with a variable histomorphology and rather aggressive clinical course.

Perivascular Epithelioid Cell Tumor of the Urinary Bladder: A Systematic Review.

Perivascular epithelioid cell tumor (PEComa) of the urinary bladder is a rare neoplasm showing distinct melanocytic and smooth muscle differentiation. We aimed to review the clinicopathologic features of bladder PEComa using all the available cases in the literature, along with 2 new cases from our database. The patients included 15 females and 15 males with a mean age of 39.2 ± 15.3 years. Painless hematuria was the most common clinical presentation. The tumors were usually well circumscribed with a mean tumor size of 4.4 ± 2.7 cm. Bladder PEComas demonstrated nests, trabeculae, or sheets of epithelioid cells with intermixed spindled cells and numerous thin-walled vessels. Immunohistochemical studies showed that the tumors were positive for HMB45 (27/27), cathepsin (4/4), SMA (20/22), and caldesmon (3/3) and were negative for pan cytokeratin (0/18) and EMA (0/4). Molecular studies revealed that PEComa was associated with the TFE3 (n = 3) and EWSR1 (n = 1) gene rearrangements. Treatment included partial cystectomy (n = 18), transurethral resection (n = 8), and radical cystectomy (n = 4). Twenty patients had no evidence of disease during a mean follow-up time of 19.4 ± 17.2 months. Two patients had recurrence, and 1 patient died of metastatic disease. In conclusion, bladder PEComas demonstrate distinct morphologic and immunohistochemical features. Although most tumors follow a benign course, a small subset may develop metastasis and cause death.

The classification of pediatric and young adult renal cell carcinomas registered on the children's oncology group (COG) protocol AREN03B2 after focused genetic testing.

BACKGROUND: Renal cell carcinomas (RCCs) are rare in young patients. Knowledge of their pathologic and molecular spectrum remains limited, and no prospective studies have been performed to date in this population. This study analyzes patients diagnosed with RCC who were prospectively enrolled in the AREN03B2 Children's Oncology Group (COG). The objective was to classify these tumors with the aid of focused genetic testing and to characterize their features. METHODS: All tumors registered as RCC by central review were retrospectively re-reviewed and underwent additional ancillary studies. Tumors were classified according to the 2016 World Health Organization classification system when possible. RESULTS: In total, 212 tumors were identified, and these were classified as microphthalmia transcription factor (MiT) translocation RCC (MiT-RCC) (41.5%), papillary RCC (16.5%), renal medullary carcinoma (12.3%), chromophobe RCC (6.6%), clear cell RCC (3.3%), fumarate hydratase-deficient RCC (1.4%), and succinate dehydrogenase-deficient RCC (0.5%). Other subtypes included tuberous sclerosis-associated RCC (4.2%), anaplastic lymphoma kinase (ALK)-rearranged RCC (3.8%), thyroid-like RCC (1.4%), myoepithelial carcinoma (0.9%), and unclassified (7.5%). MiT-RCCs were classified as either transcription factor E3 (TFE3) (93.2%) or EB (TFEB) (6.8%) translocations, and characterization of fusion partners was possible in most tumors. CONCLUSIONS: The current study delineates the frequency of distinct RCC subtypes in a large prospective series of young patients and contributes knowledge to the diagnostic, clinical, and genetic features of MiT-RCC, the most common subtype among this age group. The identification of rare subtypes expands the spectrum of RCC in young patients, supporting the need for a thorough diagnostic workup. These studies may aid in the introduction of specific therapies for different RCC subtypes in the future. Cancer 2018. © 2018 American Cancer Society.

TFE3-rearranged hepatic epithelioid hemangioendothelioma-a case report with immunohistochemical and molecular study.

A recurrent YAP1-TFE3 gene fusion has been identified in WWTR1-CAMTA1-negative epithelioid hemangioendotheliomas arising in soft tissue, bone, and lung, but not in liver. We present the first case of TFE3-rearranged hepatic epithelioid hemangioendothelioma in a 39-year-old Taiwanese woman. Computed tomography scan revealed multifocal, ill-defined nodules involving both hepatic lobes. She then underwent deceased donor liver transplantation. Histologically, the tumors in the liver explant showed a biphasic growth pattern. One component was composed of dilated and well-formed blood vessels lined by epithelioid cells with abundant eosinophilic cytoplasm, mimicking an alveolar pattern, whereas the other component was composed of cords and single cells, featuring intracytoplasmic vacuoles, separated by a myxoid stroma. The tumor cells showed vesicular nuclei and small indistinct nucleoli with mild to moderate cytologic atypia. Most tumor cells showed factor VIII, CD34, CD31, and TFE3 positivity in immunohistochemical study. Fluorescence in situ hybridization analysis for the tumor cells exhibited TFE3 gene rearrangement. The patient is currently alive, and no post-operative tumor recurrence developed during a 13-year follow-up. Awareness of this rare vasoformative variant and identification of the gene rearrangement would be helpful on differential diagnosis with other high-grade carcinoma and angiosarcoma of liver.

Nephron-sparing surgery in the treatment of pediatric renal cell carcinoma associated with Xp11.2 translocation/TFE3 gene fusions.

PURPOSE: To investigate the safety and efficacy of nephron-sparing surgery (NSS) in the treatment of pediatric Xp11.2 translocation renal cell carcinoma (RCC). METHODS: Clinical characteristics of 9 RCC children (7 males and 2 females) with Xp11.2 translocation who received NSS between January 1973 and December 2015 were retrospectively analyzed. The mean age was 7.8years (range: 4.5-13.5years). Xp11.2 translocation RCC was found in the left side in 4 patients and right in 5. 3 tumors were located in the upper pole of the kidney, 1 in the middle dorsal, 1 in the middle ventral and 4 in the lower pole. RCC presented with painless gross hematuria in 4 patients, abdominal mass in 1, and as an incidental finding by ultrasound examination in 4 patients. The mean course of hematuria was 3months (range: 1-7months). The mean tumor diameters were 3.7cm (range: 2.2-6.9cm). RESULTS: All the patients received NSS with open transperitoneal approach. The mean operative time and estimated blood loss were 115min and 40ml, respectively. The time of renal pedicle clamping was 19-25min (mean: 21.5min). No complications (such as leakage of urine, prolonged drainage or secondary bleeding) were noted. No patients experienced local recurrence during the mean of 50.1-month follow-up (range: 13-117months). Intravenous urography (IVU) or contrast-enhanced CT was conducted at 6months after surgery which showed favorable kidney function in all patients. CONCLUSION: Xp11.2 translocation RCC is a predominant pathological but biologically inert type of pediatric RCC. For Xp11.2 translocation RCC sized <4-7cm in diameter and located in one pole, NSS is safe and feasible. TYPE OF STUDY: Treatment Studies, LEVEL IV.