Solitary fibrous tumor of the lung: diagnostic challenges and surgical management

Abstract

Solitary fibrous tumors (SFTs) are rare mesenchymal neoplasms that typically arise from the pleura but may occur in various extrathoracic sites. Primary intraparenchymal pulmonary SFTs without pleural attachment are exceptionally uncommon and often pose diagnostic and therapeutic challenges. We report the case of a middle-aged female patient presenting with progressive dyspnea and a large mass in the left lower lobe on imaging. Computed tomography revealed a well-circumscribed, hypervascular mass occupying the left lower lobe. Bronchoscopic and percutaneous biopsies were nondiagnostic, and surgical resection was pursued. Intraoperatively, the tumor was found to arise from the lung parenchyma without pleural involvement. Histopathological examination demonstrated a spindle-cell neoplasm with the typical “patternless pattern,” and immunohistochemistry confirmed nuclear STAT6 positivity, establishing the diagnosis of SFT. The postoperative course was uneventful apart from a transient pulmonary embolism, which was successfully treated. The patient was discharged in good condition and is under regular radiologic surveillance. SFTs of the lung are rare and often mimic more common pulmonary tumors radiologically. Histologic confirmation with STAT6 immunohistochemistry is crucial for accurate diagnosis. Complete surgical excision remains the mainstay of treatment. Given the risk of late recurrence-especially in large tumors-long-term imaging follow-up is mandatory. This case highlights the importance of considering SFT in the differential diagnosis of large pulmonary masses, the critical role of STAT6-based histopathologic confirmation, and the necessity for prolonged surveillance even after complete resection.

Keywords

solitary fibrous tumor / lung neoplasm / intraparenchymal tumor / STAT6 immunohistochemistry / surgical resection

References

[1] Gold JS, Antonescu CR, Hajdu C, Ferrone CR, Hussain M, Lewis JJ, et al. Clinicopathologic correlates of solitary fibrous tumors. Cancer. 2002; 94: 1057-68.

[2] de Perrot M, Fischer S, Bründler MA, Sekine Y, Keshavjee S. Solitary fibrous tumors of the pleura. Ann Thorac Surg. 2002; 74: 285-93.

[3] Briselli M, Mark EJ, Dickersin GR. Solitary fibrous tumors of the pleura: eight new cases and review of 360 cases in the literature. Cancer. 1981; 47: 2678-89.

[4] Yoshida A, Tsuta K, Ohno M, Yoshida M, Narita Y, Kawai A, et al. STAT6 immunohistochemistry is helpful in the diagnosis of solitary fibrous tumors. Am J Surg Pathol. 2014; 38: 552-9.

[5] Robinson DR, Wu YM, Kalyana-Sundaram S, Cao X, Lonigro RJ, Sung YS, et al. Identification of recurrent NAB2-STAT6 gene fusions in solitary fibrous tumor by integrative sequencing. Nat Genet. 2013; 45: 180-5.

[6] Davanzo B, Emerson RE, Lisy M, Koniaris LG, Kays JK. Solitary fibrous tumor. Transl Gastroenterol Hepatol. 2018; 3: 94.

[7] Badawy M, Nada A, Crim J, Kabeel K, Layfield L, Shaaban A, et al. Solitary fibrous tumors: Clinical and imaging features from head to toe. Eur J Radiol. 2022; 146: 110053.

[8] England DM, Hochholzer L, McCarthy MJ. Localized benign and malignant fibrous tumors of the pleura. A clinicopathologic review of 223 cases. Am J Surg Pathol. 1989; 13: 640-58.

[9] Doyle LA, Vivero M, Fletcher CD, Mertens F, Hornick JL. Nuclear expression of STAT6 distinguishes solitary fibrous tumor from histologic mimics. Mod Pathol. 2014; 27: 390-5.

[10] Salas S, Resseguier N, Blay JY, Le Cesne A, Italiano A, Chevreau C, et al. Prediction of local and metastatic recurrence in solitary fibrous tumor: construction of a risk calculator in a multicenter cohort from the French Sarcoma Group (FSG) database. Ann Oncol. 2017; 28: 1979-87.

[11] Demicco EG, Wagner MJ, Maki RG, Gupta V, Iofin I, Lazar AJ, et al. Risk assessment in solitary fibrous tumors: validation and refinement of a risk stratification model. Mod Pathol. 2017; 30: 1433-42.

[12] Harrison-Phipps KM, Nichols FC, Schleck CD, Deschamps C, Cassivi SD, Schipper PH, et al. Solitary fibrous tumors of the pleura: results of surgical treatment and long-term prognosis. J Thorac Cardiovasc Surg. 2009; 138: 19-25.

[13] Lococo F, Cusumano G, Margaritora S, Cardillo G, Filosso P, Cesario A. Tapias score for predicting recurrences in resected solitary fibrous tumor of the pleura: controversial points and future perspectives emerging from an external validation. Chest. 2015; 147: e115-6.

[14] Tanaka R, Matsumoto I, Takayama T, Ohkura N, Inoue D. Preoperative assessment of pleural adhesions in patients with lung cancer based on quantitative motion analysis with dynamic chest radiography: A retrospective study. J Appl Clin Med Phys. 2023; 24: e14036.

[15] Takada I, Kudo Y, Amemiya R, Takara Y, Matubayashi J, Uchida M, et al. Thoracoscopic Resection of a Giant Solitary Fibrous Tumor in the Chest Cavity After Preoperative Arterial Embolization: A Case Report. Cureus. 2025; 17: e90612.

[16] de Perrot M, Kurt AM, Robert JH, Borisch B, Spiliopoulos A. Clinical behavior of solitary fibrous tumors of the pleura. Ann Thorac Surg. 1999; 67: 1456-9.

[17] Sung SH, Chang J, Kim J, Lee KS, Han J, Park SI. Solitary fibrous tumors of the pleura: surgical outcome and clinical course. Ann Thorac Surg. 2005; 79: 303-7.

[18] de Bernardi A, Dufresne A, Mishellany F, Blay JY, Ray-Coquard I, Brahmi M. Novel Therapeutic Options for Solitary Fibrous Tumor: Antiangiogenic Therapy and Beyond. Cancers (Basel). 2022; 14: 1064.

[19] Martin-Broto J, Mondaza-Hernandez JL, Moura DS, Hindi N. A Comprehensive Review on Solitary Fibrous Tumor: New Insights for New Horizons. Cancers (Basel). 2021; 13: 2913.

[20] Stacchiotti S, Negri T, Libertini M, Palassini E, Marrari A, De Troia B, et al. Sunitinib malate in solitary fibrous tumor (SFT). Ann Oncol. 2012; 23: 3171-9.

[21] Levard A, Derbel O, Méeus P, Ranchère D, Ray-Coquard I, Blay JY, et al. Outcome of patients with advanced solitary fibrous tumors: the Centre Léon Bérard experience. BMC Cancer. 2013; 13: 109.