Clinicopathological characteristics of renal solitary fibrous tumor

Abstract

To analyze the clinical characteristics, treatment modalities and outcomes of adult renal solitary fibrous tumors (SFT) treated at a single institution. Demographic, diagnostic, surgical, and pathological findings of patients who had undergone radical nephrectomy (RN) due to renal SFT were collected from the database of a single institution and were retrospectively reviewed. Ten patients (6 men and 4 women) were diagnosed with renal SFT in our institution between January 1, 2000 and December 31, 2016. The mean age was 50.9 ± 8.2 years (range, 38–63 years). Of the 10 patients, 6 were asymptomatic, 2 presented with flank pain, 1 presented with abdominal discomfort, and 1 presented with haematuria. Computed tomography scans were obtained for all patients. Open RN was performed on 6 patients, and laparoscopic RN was performed on 4 patients. The mean tumor size was 10.23 ± 4 cm (range, 5.3–19 cm). Pathological diagnosis revealed that the tumors in 8 patients were benign, while those in the other 2 patients were malignant renal SFT. No recurrence occurred during a mean follow-up period of 47.3 ± 21.5 months (range, 16–85 months). Renal SFT is extremely rare, and its diagnosis may be challenging because of a lack of typical imaging manifestations. RN is a safe treatment modality for benign or low-grade malignant renal SFT, ensuring favorable outcomes.

Controversial issues in soft tissue solitary fibrous tumors: A pathological and molecular review

“…The NAB2–STAT6 fusion is the molecular hallmark (Fig. d) of SFTs . Although Barthelmess et al detected a significant association between the NAB2ex6‐ STAT6ex16/17 variant and malignancy in SFTs, other authors have reported that no fusion variants are associated with malignancy …”

“…Many of the histological variants reveal a focal patternless architecture, and variably fibro‐collagenous stroma . NAB2‐STAT6 was discovered as a novel fusion gene of SFTs, and STAT6 immunoexpression has been established as a surrogate marker of the NAB2‐STAT6 gene fusion, expression of this protein representing a very sensitive and specific diagnostic tool …”

“…Nevertheless, few studies have evaluated the role of molecular alterations in malignant SFTs compared to nonmalignant SFTs . Currently, mitotic activity (≥4/10 HPFs), telomerase reverse transcriptase gene (TERT) promoter mutations, and/or TP53 mutations are considered to better correlate with tumor aggressiveness, although inclusion of molecular alterations in the widely‐used risk stratification models is still pending . In this study, the authors review and discuss current knowledge on SFT, including their wide morphologic spectrum, immunohistochemical and molecular findings and differential diagnosis.…”

“…[23][24][25][26][27][28][29][30][31][32][33] Currently, mitotic activity (≥4/10 HPFs), telomerase reverse transcriptase gene (TERT) promoter mutations, and/or TP53 mutations are considered to better correlate with tumor aggressiveness, although inclusion of molecular alterations in the widely-used risk stratification models is still pending. [8][9][10][23][24][25][26][27][28][29][30][31][32][33][35][36][37][38][39][40][41][42][43][44][45][46][47][48][49][50][51] In this study, the authors review and discuss current knowledge on SFT, including their wide morphologic spectrum, immunohistochemical and molecular findings and differential diagnosis. We focus on the following problematic items in SFT: (i) the diverse morphologic spectrum: 'the great simulator;' (ii) malignant transformation or dedifferentiation; (iii) current risk stratification systems; and (iv) molecular factors associated with clinical evolution.…”

“…[1][2][3][4][5][6][7][8][9][22][23][24][25][26][27][28][29][30] NAB2-STAT6 was discovered as a novel fusion gene of SFTs, and STAT6 immunoexpression has been established as a surrogate marker of the NAB2-STAT6 gene fusion, expression of this protein representing a very sensitive and specific diagnostic tool. 4,7,9,18,[22][23][24][25][26][30][31][32][33][34][35][36][37][38][39][40][41][42][43][44][45][46][47] Although several publications have discussed the histological, clinical or molecular criteria for malignancy in SFT, no feasible determinant of malignancy has yet been established for practical use. 2,[8][9][...…”