Salvage surgery for a giant recurrent solitary fibrous tumor with multiorgan invasion 13 years after initial resection: a case report

Solitary fibrous tumor (SFT) is a rare mesenchymal neoplasm with unpredictable biological behavior. Late recurrence—defined as relapse occurring 10 years or more after initial resection—is a recognized but uncommon feature, and the optimal management of giant locally recurrent tumors with extensive multiorgan invasion remains challenging. A 63-year-old male presented with a giant right thoracic mass discovered incidentally on chest CT following a traffic accident, 13 years after undergoing right lower lobe tumor resection for a histologically confirmed SFT. The recurrence measured 11.5 × 9.8 × 14.1 cm and demonstrated direct invasion of the right middle and lower lobes, chest wall (5th–6th intercostal space), diaphragm, and pericardium with encasement of the inferior pulmonary vein. Preoperative PET-CT confirmed no distant metastases. The patient underwent resection of the right middle and lower lobes, involved chest wall, pericardium (3 × 4 cm), and diaphragm (5 × 2 cm defect). The diaphragmatic defect was primarily repaired with direct sutures without prosthetic material. Total operative time was 5.5 h with 300 mL blood loss. Pathological examination confirmed recurrent SFT with STAT6 nuclear positivity, Bcl-2(+), CD99(+), CD34 (focal+ with extensive loss), heterogeneous p53 expression, Ki-67 up to 10%, classified as atypical SFT with focal malignant transformation, intermediate risk grade, although additional adverse features suggest the clinical risk may be higher. All surgical margins were negative (R0 resection). The postoperative course was uneventful apart from transient atrial fibrillation, and the patient was discharged on postoperative day 5. This case demonstrates that aggressive salvage surgery can achieve R0 resection even for giant locally recurrent SFTs with extensive multiorgan invasion occurring more than a decade after initial surgery. The 13-year recurrence interval underscores the importance of lifelong surveillance for SFT patients, as indolent biological behavior can be followed by aggressive local progression. The presence of CD34 loss and heterogeneous p53 expression in the recurrent tumor supports the concept of biological progression toward a more aggressive phenotype, warranting rigorous long-term surveillance.