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Abstract
Solitary fibrous tumor is a rare mesenchymal neoplasm, most commonly arising from the pleura, with infrequent involvement of the sinonasal tract. Malignant transformation is uncommon and poses significant diagnostic challenges due to overlapping histomorphology with other spindle cell neoplasms. We report a case of malignant solitary fibrous tumor of the sinonasal region in a 52-year-old male who presented with a recurrent nasal mass. Radiologic evaluation revealed an infiltrative lesion arising from the maxillary sinus. Histopathological examination and immunohistochemistry, including STAT6 nuclear positivity, confirmed the diagnosis of malignant SFT. This case highlights the importance of integrating clinical, radiologic, histopathologic, and immunohistochemical findings for accurate diagnosis of this rare entity.
SFT (Solitary Fibrous Tumor) is a mesenchymal neoplasm of fibroblastic origin, classified as an intermediate (rarely metastasizing) tumor in the WHO Classification of Soft Tissue and Bone Tumors (5th edition).[1] While the pleura is the most common site, extrapleural locations such as the meninges, abdominal cavity, trunk, extremities, and head and neck region have been documented. Sinonasal involvement is particularly rare, accounting for approximately 5% of cases.
Malignant SFTs exhibit aggressive behaviour with potential for local recurrence and distant metastasis. Due to histological overlap with other spindle cell neoplasms of the sinonasal tract, definitive diagnosis requires immunohistochemistry and molecular correlation. We present a rare case of malignant sinonasal SFT with emphasis on diagnostic approach and differential considerations.
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References
- Demicco EG, Fritchie KJ, Han A. Solitary fibrous tumour. In: WHO Classification of Tumours Editorial Board, ed. World Health Organisation classification of soft tissue and bone tumours. 5th edn. Lyon, France: IARC Press 2019:104-8.
- Tariq MU, Din NU, Abdul-Ghafar J, et al. The many faces of solitary fibrous tumor; diversity of histological features, differential diagnosis and role of molecular studies and surrogate markers in avoiding misdiagnosis and predicting the behavior. Diagn Pathol 2021;16:32.
- Doyle LA, Vivero M, Fletcher CDM, et al. Nuclear expression of STAT6 distinguishes solitary fibrous tumor from histologic mimics. Mod Pathol 2014;27:390-5.
- Fletcher CDM, Bridge JA, Lee JC. Extrapleural solitary fibrous tumour. In: Fletcher CDM, Bridge JA, Hogendoorn PCW, et al, eds. WHO Classification of tumours of soft tissue and bone. Lyon: IARC 2013:80-2.
- Kao YC, Lin PC, Yen SL, et al. Clinicopathological and genetic heterogeneity of the head and neck solitary fibrous tumours: a comparative histological, immunohistochemical and molecular study of 36 cases. Histopathology 2016;68(4):492-501.
- Cox DP, Daniels T, Jordan RC. Solitary fibrous tumor of the head and neck. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2010;110(1):79-84.
- Ganly I, Patel SG, Stambuk HE, et al. Solitary fibrous tumors of the head and neck: a clinicopathologic and radiologic review. Arch Otolaryngol Head Neck Surg 2006;132(5):517-25.
References
Demicco EG, Fritchie KJ, Han A. Solitary fibrous tumour. In: WHO Classification of Tumours Editorial Board, ed. World Health Organisation classification of soft tissue and bone tumours. 5th edn. Lyon, France: IARC Press 2019:104-8.
Tariq MU, Din NU, Abdul-Ghafar J, et al. The many faces of solitary fibrous tumor; diversity of histological features, differential diagnosis and role of molecular studies and surrogate markers in avoiding misdiagnosis and predicting the behavior. Diagn Pathol 2021;16:32.
Doyle LA, Vivero M, Fletcher CDM, et al. Nuclear expression of STAT6 distinguishes solitary fibrous tumor from histologic mimics. Mod Pathol 2014;27:390-5.
Fletcher CDM, Bridge JA, Lee JC. Extrapleural solitary fibrous tumour. In: Fletcher CDM, Bridge JA, Hogendoorn PCW, et al, eds. WHO Classification of tumours of soft tissue and bone. Lyon: IARC 2013:80-2.
Kao YC, Lin PC, Yen SL, et al. Clinicopathological and genetic heterogeneity of the head and neck solitary fibrous tumours: a comparative histological, immunohistochemical and molecular study of 36 cases. Histopathology 2016;68(4):492-501.
Cox DP, Daniels T, Jordan RC. Solitary fibrous tumor of the head and neck. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2010;110(1):79-84.
Ganly I, Patel SG, Stambuk HE, et al. Solitary fibrous tumors of the head and neck: a clinicopathologic and radiologic review. Arch Otolaryngol Head Neck Surg 2006;132(5):517-25.