[Clinical characteristics of abdominal solitary fibrous tumor: an analysis of 18 cases]

Solitary fibrous tumor involving urinary bladder: a case report and literature review

Solitary fibrous tumor (SFT) is a rare fibroblast stroma tumor involving the mediastinum and pleura. We herein describe an SFT of bladder which is extremely rare and review 29 similar cases in the last decades. We present a case of a 52-year-old male patient who suffered from urinary urgency and frequency for 12 months. Non-contrast computed tomography (CT) showed a slightly high density calcified mass with 70 mm × 61 mm in diameter. Contrast-enhanced CT demonstrated the mass was slightly enhanced. Cystoscopy revealed a huge mass with flat surface. Histopathological review of the biopsy specimens could not confirm the diagnosis. Partial cystectomy was then performed and the diagnosis of SFT was confirmed by immunohistochemistry. The patient is doing well at 12 months follow-up without recurrence and metastasis. In conclusion, the diagnosis of SFT involving bladder should combine clinical presentation and imaging features. Complete surgical resection is the primary method and long-term follow-up is necessary.

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

Solitary fibrous tumor (SFT) is a rare clinical tumor, defined as a mesenchymal tumor of fibroblastic origin. A classic SFT is benign in most cases, but its clinical behavior is unpredictable. Lately, molecular analyses has discovered that almost all SFTs harbor an NAB2‐STAT6 fusion gene, which is considered specific to this tumor type. Recent studies have suggested that nuclear STAT6 immunoreactivity is a highly sensitive and specific marker of SFTs and can be helpful when diagnosis is inconclusive by conventional methods. We herein report the case of a rare malignant solitary fibrous tumor occurring in the mediastinal pleura. An 82‐year‐old Chinese man with intermittent breathlessness was referred to our hospital. Chest CT showed a significantly enhanced irregular huge soft tissue mass in the anterior mediastinal area. After radical resection, the immunohistochemistry staining results of the sample showed that STAT6 was negative. The final diagnosis was confirmed by qualitative endpoint reverse transcriptase‐polymerase chain reaction technique, showing positive NAB2ex4‐STAT6ex2 fusion.