Immunohistochemical analysis of a giant solitary fibrous tumor of the ovary with aggressive recurrence

Background: Solitary fibrous tumor (SFT) is an uncommon spindle cell neoplasm with fibroblastic differentiation. Initially identified as a tumor of the pleura, SFT has since been documented in various extrapleural sites; however, its occurrence outside the thoracic cavity remains infrequent. Case: We describe the case of a 72-year-old female who presented with progressive abdominal distension. Imaging studies revealed a solid ovarian mass, prompting bilateral salpingo-oophorectomy and total hysterectomy. The excised tumor, weighing approximately 7000 grams, had a smooth external surface without evidence of capsular rupture or adherence to adjacent structures. Histopathological and immunohistochemical evaluations, including signal transducer and activator of transcription 6 (STAT6) and cluster of differentiation 34 (CD34) expression, established the diagnosis of ovarian SFT. The patient was lost to follow-up but returned 14 months postoperatively with recurrent abdominal swelling. Exploratory laparotomy identified extensive tumor invasion into the right external iliac vein, ureter and ileum, rendering complete resection unfeasible. The recurrent mass, upon excision, weighed approximately 6000 grams. Conclusion: While SFTs are typically regarded as indolent, their biological behavior remains unpredictable, with potential for both local recurrence and distant metastasis. This case illustrates the aggressive nature of recurrent ovarian SFT and emphasizes the necessity for prolonged clinical monitoring. Due to the rarity of ovarian SFTs, further case studies are essential to enhance understanding of their clinical trajectory and guide optimal management strategies.