Pelvic solitary fibrous tumor, historically classified as hemangiopericytoma, presenting with venous compression and pelvic congestion: A case report

Introduction: Solitary fibrous tumour is a rare fibroblastic mesenchymal neoplasm historically classified as hemangiopericytoma. Although it can occur at almost any anatomical site, pelvic involvement is uncommon, and symptoms often develop late as a consequence of progressive mass effect. Case presentation: A 69-year-old man presented with abdominal pain, progressive swelling of the right lower limb, and paraesthesia. Laboratory investigations revealed mild anaemia, elevated fibrinogen levels, and mildly increased C-reactive protein, while serum tumour markers remained within normal limits. Multidetector computed tomography demonstrated a large lobulated hypervascular abdominopelvic mass with heterogeneous enhancement and central necrosis. Computed tomographic angiography revealed compression of the right iliac vein, femoral venous dilatation, and marked pelvic venous congestion. Colour Doppler ultrasonography demonstrated abnormal venous flow without definitive evidence of thrombosis. Conclusion: Solitary fibrous tumour is a rare but clinically significant entity that should be considered in the differential diagnosis of large hypervascular pelvic masses. A multidisciplinary approach is essential for optimal treatment planning, while surgical resection remains the primary therapeutic modality.