Solitary Fibrous Tumor



Solitary Fibrous Tumor


Khin Thway, BSc, MBBS, FRCPath









Hematoxylin & eosin shows a solitary fibrous tumor, with spindle to ovoid cells in a collagenous stroma and interspersed hemangiopericytic vessels image.






CD34 immunohistochemistry shows characteristic diffuse strong cytoplasmic and membranous positivity throughout the tumor.


TERMINOLOGY


Abbreviations



  • Solitary fibrous tumor (SFT)


Synonyms



  • Localized fibrous mesothelioma, localized fibrous tumor, submesothelial fibroma, localized fibroma, subpleural fibroma


Definitions



  • Fibroblastic mesenchymal tumor with prominent branching (hemangiopericytoma-like) vascular pattern



    • Initially described in pleura but subsequently described in almost any organ or site


    • Many previously diagnosed soft tissue hemangiopericytomas are probably solitary fibrous tumors


  • Closely related tumors



    • Lipomatous hemangiopericytoma


    • Giant cell angiofibroma


ETIOLOGY/PATHOGENESIS


Unknown



  • Initially considered mesothelial


  • Now accepted as mesenchymal tumor


CLINICAL ISSUES


Epidemiology



  • Age



    • Adults (range: 20-70 years)


    • Occasionally in children and adolescents


  • Gender



    • M = F


Site



  • Deep soft tissue


  • Viscera


  • Subcutaneous tissue and very rarely at cutaneous sites


  • Head and neck, including orbit and intracranial sites


  • Extrapleural lesions more frequent than pleural


Presentation



  • Slow growing


  • Painless mass



    • Rarely paraneoplastic syndrome of hypoglycemia due to production of insulin-like growth factor


Treatment



  • Surgical approaches



    • Simple surgical resection for benign SFT


    • More extensive surgery for malignant SFT


  • Adjuvant therapy



    • Combination of radiation therapy and chemotherapy in malignant SFT


Prognosis



  • Long-term follow-up is mandatory due to unpredictable behavior of SFT


  • Most are benign


  • Up to 15% behave aggressively


  • Most tumors with histologically “benign” morphology do not recur or metastasize


  • Histologically malignant tumors usually behave aggressively


MACROSCOPIC FEATURES


General Features



  • Lobulated, circumscribed mass



    • Malignant tumors may be locally infiltrative


  • Firm gray-white or brown cut surface


  • Occasional cystic degeneration or hemorrhage


Size



  • 1-20 cm (most 5-10 cm)



MICROSCOPIC PATHOLOGY


Histologic Features

Jul 9, 2016 | Posted by in PATHOLOGY & LABORATORY MEDICINE | Comments Off on Solitary Fibrous Tumor
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