Malignant solitary fibrous tumor occurring in the mediastinal pleura showing NAB2ex4‐STAT6ex2 fusion and negative STAT6 immunohistochemistry: A case report

Zhang, Peng; Xiong, Kai; Lv, Peng; Zhang, Hui; Wang, Yuanguo; Yang, Zhaoyu; Tao, Ziyou; Song, Wenjing

doi:10.1111/1759-7714.13395

Cited by 7 publications

(5 citation statements)

References 8 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Zhang et al. also reported a case with mediastinal malignant SFT carrying a NAB2-STAT6 fusion gene but negative STAT6 immunohistochemical staining ( 20 ). In the present case, the primary differentiated tumor was positive for CD34 and STAT6 but the primary dedifferentiated tumor and lung/liver metastases were completely negative ( Figures 3C, D, H, I ).…”

Section: Discussionmentioning

confidence: 99%

Case Report: Molecular Characterization of Aggressive Malignant Retroperitoneal Solitary Fibrous Tumor: A Case Study

et al. 2021

View full text Add to dashboard Cite

Solitary fibrous tumors (SFT) are mesenchymal neoplasms with a favorable prognosis usually originating from the visceral pleura. Rarely, they may occur at various extrapleural sites and show malignant behavior coupled with dedifferentiation. NAB2-STAT6 fusion gene and STAT6 nuclear expression are biomarkers for diagnosis of SFT in addition to CD34, Bcl-2, and CD99. Furthermore, several reports have shown specific NAB2-STAT6 fusion variants and loss of STAT6 protein expression are associated with malignancy. We report a rare case of retroperitoneal SFT which rapidly progressed to death within 35 days after admission. Autopsy found a primary tumor containing both benign and malignant histologies, with multiple metastatic sites similar to the malignant, dedifferentiated tumor. STAT6 was detected in the primary differentiated tumor but not in the primary dedifferentiated tumor or lung/liver metastases. However, the NAB2-STAT6 fusion gene (NAB2ex6/STAT6ex16 variant) was detected in the primary tumor and lung/liver metastases. Intriguingly, fusion gene expression at the transcriptional level was downregulated in the dedifferentiated tumors compared to the differentiated tumor. We further performed target DNA sequencing and found gene mutations in TP53, FLT3, and AR in the dedifferentiated tumors, with TP53 mutations especially found among them. We demonstrate that downregulation of NAB2-STAT6 fusion gene at the transcriptional level is associated with malignant SFT for the first time. Moreover, the present study supports the idea that TP53 mutations promote malignancy in SFTs.

show abstract

Section: Discussionmentioning

confidence: 99%

Case Report: Molecular Characterization of Aggressive Malignant Retroperitoneal Solitary Fibrous Tumor: A Case Study

et al. 2021

View full text Add to dashboard Cite

show abstract

“…The most valuable positive markers of SFT immunohistochemistry were CD34, CD99, Bcl-2, and vimentin, cytokeratin (CK) was always negative. Recent studies have shown that nuclear STAT6 immunoreactivity is a highly sensitive and specific marker of SFT, and almost all SFT contain NP2-STAT6 fusion gene (39). The positive expression rate of STAT6 was even 100% in benign SFT but decreased in malignant SFT (40).…”

Section: Discussionmentioning

confidence: 99%

Rapidly growing solitary fibrous tumors of the pleura: a case report and review of the literature

Zuo¹,

Zhou²,

Sun³

et al. 2020

Ann Transl Med

View full text Add to dashboard Cite

A solitary fibrous tumor (SFT) is a rare spindle cell tumor-derived from mesenchymal cells. It may be linked to the fusion of the NAB2-STAT6 gene caused by 12q chromosome rearrangement. It can occur in the connective tissue of any part of the body; however, it is most common in the pleura. Solitary fibrous tumors of the pleura (SFTP) are a persistent painless mass with slow growth. With the increase of the tumor, there will be corresponding compression symptoms. Pleural effusion is rare, and the cytology of pleural effusion is mostly negative. Occasionally, SFTP can induce paraneoplastic syndrome, distant metastasis, and malignant transformation. Lung function may have mild to moderate restrictive ventilation dysfunction. CT is a crucial method for the clinical diagnosis of SFTP. The histopathological features of SFTP are the coexistence of sparse and dense areas. CD34, CD99, Bcl-2, and vimentin are the most valuable immunohistochemical markers.The positive expression rate of STAT6 in benign SFT was even 100%. Adhesion or unclear boundary with surrounding tissues, pleural effusion or calcification, tumors with a maximum diameter greater than 10 cm, invasive growth, uneven density, metastasis or recurrence, paraneoplastic syndrome, moderate to severe cell heterogeneity, high Ki67 proliferation index, and low STAT6 expression suggest SFTP may be a malignant tumor. Gene analysis on next generation sequencing may help reveal the mutation characteristics of SFTP. Complete tumor resection is the gold standard of SFTP. Resectability is the most important prognostic factor. Age, size, mitosis, and necrosis are considered risk stratification factors for prognosis. Fortunately, 80% of SFTP are benign and have anexcellentprognosis but need long-term follow-up.We report a case of rapidly growing tumor with pleural effusion within 9 months, who was surgically treated and is currently under follow-up. And the literature is reviewed.

show abstract

“…Prior studies have claimed high specificity for STAT6 in the diagnosis of SFT 28,31,32. STAT6 IHC-negative SFTs have been rarely reported, and loss of STAT6 and CD34 has been associated with malignant biologic behavior in some cases 33. However, these cases demonstrated the NAB2::STAT6 translocation by molecular studies confirming the diagnosis; it is unclear whether the loss of these markers indicates a false-negative secondary to preanalytical variables or loss of expression through some other mechanism related to tumorigenesis.…”

Section: Discussionmentioning

confidence: 99%

Epithelioid and Clear Cell Solitary Fibrous Tumors

Suster

Mackinnon

Mejbel

et al. 2022

American Journal of Surgical Pathology

View full text Add to dashboard Cite

Solitary fibrous tumors (SFTs) are ubiquitous soft tissue neoplasms known for their protean histology and potentially aggressive behavior. Although most cases are composed of a monotonous proliferation of spindle cells, some tumors show unusual cytologic features. We have studied 13 SFTs that were characterized by a predominant population of round epithelioid cells with abundant eosinophilic cytoplasm and clear cell changes. The tumors occurred in 8 women and 5 men, aged 36 to 80 years (mean=63 y), and were located within the orbit (3), lower extremity (3), retroperitoneum (2), abdominal cavity (2), and superficial soft tissues of the neck, pelvis, and pubis (1 each). The tumors measured from 3.5 to 24.5 cm. Using a risk assessment system, 6 cases were stratified as low-risk tumors; 3 of these showed no evidence of recurrence or metastases from 6 to 18 years, and 1 tumor in the orbit recurred and led to the patient’s demise. Five cases were of intermediate risk; clinical follow-up showed no evidence of recurrence or metastases from 3 to 4 years in 3 patients, and 1 patient suffered a recurrence 4 years after diagnosis. Two cases were high risk; 1 patient died after 1 year and the second patient experienced local recurrence at 4 years. Immunohistochemical studies showed nuclear positivity for STAT6 in 10 cases. CD34 immunohistochemistry was positive in 11 cases. A NAB2::STAT6 rearrangement was present in all cases. Epithelioid and clear cell SFT should be considered in the differential diagnosis of soft tissue neoplasms with epithelioid and clear cell morphology.

show abstract

Malignant solitary fibrous tumor occurring in the mediastinal pleura showing NAB2ex4‐STAT6ex2 fusion and negative STAT6 immunohistochemistry: A case report

Cited by 7 publications

References 8 publications

Case Report: Molecular Characterization of Aggressive Malignant Retroperitoneal Solitary Fibrous Tumor: A Case Study

Case Report: Molecular Characterization of Aggressive Malignant Retroperitoneal Solitary Fibrous Tumor: A Case Study

Rapidly growing solitary fibrous tumors of the pleura: a case report and review of the literature

Epithelioid and Clear Cell Solitary Fibrous Tumors

Contact Info

Product

Resources

About