Granular cell tumors overexpress TFE3 without gene rearrangement: Evaluation of immunohistochemistry and break-apart FISH in 45 cases

Evaluation of TRIM63 RNA in situ hybridization (RNA-ISH) as a potential biomarker for alveolar soft-part sarcoma (ASPS)

Alveolar soft-part sarcoma (ASPS) is a rare soft tissue tumor with a broad morphologic differential diagnosis. While histology and immunohistochemistry can be suggestive, diagnosis often requires exclusion of other entities followed by confirmatory molecular analysis for its characteristic ASPSCR1-TFE3 fusion. Current stain-based biomarkers (such as immunohistochemistry for cathepsin K and TFE3) show relatively high sensitivity but may lack specificity, often showing staining in multiple other entities under diagnostic consideration. Given the discovery of RNA in situ hybridization (RNA-ISH) for TRIM63 as a sensitive and specific marker of MiTF-family aberration renal cell carcinomas, we sought to evaluate its utility in the workup of ASPS. TRIM63 RNA-ISH demonstrated high levels (H-score greater than 200) of expression in 19/20 (95%) cases of ASPS (average H-score 330) and was weak or negative in cases of paraganglioma, clear cell sarcoma, rhabdomyosarcoma, malignant epithelioid hemangioendothelioma, as well as hepatocellular and adrenal cortical carcinomas. Staining was also identified in tumors with known subsets characterized by TFE3 alterations such as perivascular epithelioid cell neoplasm (PEComa, average H-score 228), while tumors known to exhibit overexpression of TFE3 protein without cytogenetic alterations, such as melanoma and granular cell tumor, generally showed less TRIM63 ISH staining (average H-scores 147 and 96, respectively). Quantitative assessment of TRIM63 staining by RNA-ISH is potentially a helpful biomarker for tumors with molecular TFE3 alterations such as ASPS.

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.

Clinicopathological features and prognosis of TFE3-positive renal cell carcinoma

Background

This study aimed to investigate the expression profile of TFE3 in renal cell carcinoma (RCC) and the clinicopathological features as well as prognosis of TFE3-positive RCC.

Methods

Tissue sections from 796 patients with RCC were collected for immunohistochemical staining of TFE3. Molecular TFE3 rearrangement tests were also carried out on the TFE3-positive RCCs using fluorescence in situ hybridization and RNA-sequencing assays. Both clinicopathological features and follow-up information were collected for further analysis.

Results

The present study showed that 91 patients with RCC (91/796, 11.4%) were TFE3 positive expression but only 31 (31/91, 34.1%) of the patients were diagnosed with Xp11.2 translocation RCC. Further, it was found that the patients with TFE3-positive RCCs were more likely to develop lymph node and distant metastasis at diagnosis as well as presented a significantly higher WHO/ISUP nuclear grade and AJCC stage as compared with patients with TFE3-negative RCCs (p<0.01). Results of univariate and multivariate analyses showed that TFE3 positive expression was an independent prognostic factor associated with poor progression-free survival. Further, the findings of survival analysis showed that patients with positive TFE3 expression showed a shorter progression-free survival as compared with the patients with negative expression of TFE3 (p<0.001). In addition, results of the survival analysis found that there was no significant difference in progression-free survival between the Xp11.2 translocation RCC and TFE3-positive non-Xp11.2 translocation RCC groups (p=0.9607).

Conclusion

This study found that nuclear TFE3 expression is not specific to the Xp11.2 translocation RCC. Moreover, the positive TFE3 expression is associated with tumor progression and poor prognosis in patients with RCC irrespective of the presence of TFE3 translocation.

Clinicopathologic and molecular features of vascular tumors in a series of 118 cases

AIMS

Vascular tumors are composed of benign, intermediate, and malignant lesions. The diagnosis is challenging because some entities demonstrate overlapping morphologies and harbor the same genetic alterations. We describe herein a cohort of vascular tumors with clinicopathologic, immunohistochemical, and molecular features.

METHODS AND RESULTS

118 vascular tumors including 56 angiosarcomas, 18 epithelioid haemangioendotheliomas (EHE), 25 epithelioid haemangiomas (EH), 8 pseudomyogenic haemangioendotheliomas (PHE), 1 papillary intralymphatic angioendothelioma (PILA), 2 kaposiform haemangioendotheliomas (KHE), 3 Kaposi sarcomas, 2 retiform haemangioendotheliomas (RHE), and 3 anastomosing haemangiomas were assessed. FOSB, c-Fos, CAMTA1, and TFE3 expression and gene rearrangements were analyzed by immunohistochemical staining and FISH, respectively. Our results showed that FOSB expression was diffusely positive in all 8 PHEs, focally or sparsely in 12 EHs, and in 2 angiosarcomas. C-FOS expression was sparsely to diffusely positive in 15 EHs, focally or sparsely in 17 angiosarcomas, 1 EHE, 1 Kaposi sarcoma, and 1 PHE. CAMTA1 expression was positive in only 12 EHEs. TFE3 expression was focally or sparsely positive in all 8 PHEs, 22 angiosarcomas, 6 EHEs, 3 EHs, 2 Kaposi sarcomas, and 2 AHs. FOSB rearrangement was found in 5 PHEs, FOS rearrangement only in 1 EH, CAMTA1 rearrangement in 4 EHEs.

CONCLUSIONS

FOSB and CAMTA1 are useful diagnostic markers for PHE and EHE, respectively. FOSB and FOS fusion represent a subset of epithelioid haemangioma. TFE3 is not a diagnostically meaningful marker in a majority of vascular tumors. The combined utility of these markers will facilitate the differential diagnosis in vascular tumors with morphologic overlap.

A review of neoplasms with MITF/MiT family translocations

Microphthalmia-associated transcription factor (MITF/MiT) family is a group of basic helix-loop-helix leucine zipper (bHLH-LZ) transcription factors including TFE3 (TFEA), TFEB, TFEC and MITF. The first renal neoplasms involving MITF family translocation were renal cell carcinomas with chromosome translocations involving ASPL-TFE3/t(X;17)(p11.23;q25) or MALAT1-TFEB/t(6;11)(p21.1;q12), and now it is known as MiT family translocation RCC in 2016 WHO classification. Translocations involving MITF family genes also are found in other tumor types, such as perivascular epithelioid cell neoplasm (PEComa), Alveolar soft part sarcoma (ASPS), epithelioid hemangioendothelioma, ossifying fibromyxoid tumor (OFMT), and clear cell tumor with melanocytic differentiation and ACTIN-MITF translocation. In this review, we summarize the features of different types of neoplasms with MITF family translocations.

Update from the 5th Edition of the World Health Organization Classification of Head and Neck Tumors: Tumours of the Oral Cavity and Mobile Tongue

The fifth chapter of the upcoming fifth edition of the 2022 World Health Organization Classification of Tumours of the Head and Neck titled Tumours of the oral cavity and mobile tongue, has had some modifications from the 2017 fourth edition. A new section "Non-neoplastic Lesions", introduces two new entries: necrotizing sialometaplasia and melanoacanthoma. The combined Oral potentially malignant disorders and Oral epithelial dysplasia section in the 2015 WHO has now been separated and submucous fibrosis and HPV-associated dysplasia are also discussed in separate sections. Carcinoma cuniculatum and verrucous carcinoma are described in dedicated sections, reflecting that the oral cavity is the most common location in the head and neck for both these entities which have distinct clinical and histologic features from conventional squamous cell carcinoma. This review summarizes the changes in Chapter 5 with special reference to new additions, deletions, and sections that reflect current clinical, histological, and molecular advances.

Hemangioblastoma: clinicopathologic study of 42 cases with emphasis on TFE3 expression

Hemangioblastomas (HBs) histologically overlap with TFE3 rearrangement-associated tumors, which present as alveolar architecture and clear or eosinophilic granular cytoplasm. However, whether TFE3 is expressed in HBs remains unexplored. Herein, we analyzed the clinicopathologic features of 42 HBs emphasizing studies of TFE3 expression. Of 42 cases, 38 were sporadic and 4 were regarded as a part of von Hippel-Lindau (VHL) syndrome according to clinical presentation. Nineteen patients were male and 23 were female. Patient age ranged from 17 to 70 years (median 43). Tumor size ranged from 0.4 to 4.8 cm (mean 2.2 cm). Follow-up ranged from 1 to 60 months and 6 patients developed recurrence. Immunohistochemistry staining showed that 36 (86%) of 42 HBs expressed TFE3 in nuclei of tumor cells, of which 21 were evaluated as high TFE3 expression levels. Increased TFE3 expression was significantly associated with older ages (P=0.018) and larger tumor size (P=0.001). Seventeen HBs with high TFE3 expression were negative for rearrangement and amplification of TFE3 by FISH analysis, 3 of which including 2 sporadic and 1 VHL-related HBs demonstrated trisomies or tetrasomies of X-chromosome in 7%~18% of tumor cells. All 3 cases occurred in female, presented with a larger tumor size and displayed a similar morphologic appearance with high cellularity and hyperchromatic nuclei. Our study first reports TFE3 expression and its clinicopathological relevance in HBs. We hypothesize that TFE3 might be involved in the pathogenesis of non-VHL-related HBs. Furthermore, HBs with strong TFE3 expression should be differentiated from brain-metastatic TFE3-rearranged tumors.

Epithelioid Cutaneous Mesenchymal Neoplasms: A Practical Diagnostic Approach

Epithelioid cells are rounded or polygonal cells with abundant eosinophilic or clear cytoplasm and ovoid to round nuclei, superficially resembling epithelial cells. Cutaneous mesenchymal neoplasms composed predominantly or exclusively of epithelioid cells are relatively uncommon and can cause considerable diagnostic difficulties due to overlapping histologic features among heterogeneous groups of tumors. Familiarity with practical diagnostic approaches and recognition of key histopathologic features are important for correct diagnosis and management. This review summarizes the histologic features of epithelioid cutaneous mesenchymal neoplasms and discusses their differential diagnoses from malignant melanomas and carcinomas.