Diagnosis and management of an extremely rare solitary fibrous tumor in the retropubic space of Retzius: A case report

INTRODUCTION AND IMPORTANCE: Solitary fibrous tumors (SFTs), rare mesenchymal tumors, occur in diverse locations. Retroperitoneal and pelvic SFTs are extremely uncommon, challenging to identify due to vague clinical and radiological features. We present a high-risk SFT case in the retropubic Retzius space. CASE PRESENTATION: A 56-year-old woman with diabetes and bronchial carcinoid tumor had abdominal pain. Physical exam revealed hypogastric and pelvic masses. MRI showed a 16.5x12x8cm mass near the bladder. Initial laparotomy deemed it unresectable; biopsy indicated grade 2 FNCLCC mesenchymal tumor. In a second surgery, a 20 cm mass was successfully removed from the Retzius space. Histopathology confirmed SFT. Due to vaginal involvement, adjuvant radiotherapy was given. After 12 months, clinical and radiological follow-up showed remission. Unusual SFT location and successful treatment highlight the importance of comprehensive assessment and multidisciplinary approach in managing these rare tumors. CLINICAL DISCUSSION: Solitary fibrous tumors (SFTs) are rare mesenchymal neoplasms, often found in extremities but seldom in the abdomen. Diagnosis is challenging due to vague symptoms and imaging. This case discusses an unusual SFT location in the pelvic space, requiring surgical removal. SFTs are typically benign but can be malignant, requiring wide resection and potential adjuvant therapy. CONCLUSION: Diagnosing SFTs can be difficult because of their non-specific clinical and radiological characteristics, but imaging studies and biopsies can aid in the diagnosis. The preferred treatment for SFTs is surgical removal with clear margins, and regular follow-up is essential to watch for any signs of recurrence.