Document Type

Conference Proceeding

Publication Date

5-2-2025

Abstract

Introduction Solitary Fibrous Tumours (SFT) are rare mesenchymal tumours. Although initially described pleural in origin, they can arise from virtually any site. SFTs of retroperitoneal origin are especially rare, with limited literature on their management. Here we present a unique case of an aggressive recurrent retroperitoneal SFT causing mass effect leading to obstructive uropathy. Brief case description A 47-year-old Hispanic man without past medical history presented to a neighboring hospital with months-long abdominal pain and urinary retention. CT showed a 14x12x12 cm pelvic mass that could not be separated from the prostate, together with right hydroureteronephrosis. He was discharged with a catheter in his urethra and recommended for follow-up in urology. A month later, he presented at our hospital with a dislodged catheter. His vital signs were stable, although his abdomen was found to have a tender mass. Repeat CT showed a similar mass. The catheter was replaced, and the CT-guided biopsy showed a solitary fibrous tumor (SFT) with STAT6 and CD34 expression. Four months after his initial presentation, the patient underwent a radical cystoprostatectomy with ileal conduit and tumor resection. The biopsy confirmed SFT with high malignant potential with deep margins focally invaded by malignant cells. Nine months after initial presentation, the patient returned complaining of abdominal pain. CT showed a resurgent right mesenteric mass of size 9.7 cm, which on biopsy revealed to be a spindle-cell neoplasm consistent with SFT. Within two weeks, the mass grew to 18x10x14 cm. Chemotherapy with dacarbazine and doxorubicin was started, but there was progressive growth and further chemotherapy was not possible due to lack of insurance. 14 months after presentation, the patient developed obstructive uropathy and urosepsis, for which a nephrostomy tube was placed. Over the next six months, the mesenteric mass grew to 32 cm, compressing the abdomen and pelvis. The patient's condition worsened, which precluded further chemotherapy or surgical intervention. 15 months after the initial presentation, he was hospitalized due to septic shock. After goals-of-care discussions with the patient and family, the patient transitioned to a hospice service and passed away over the next few days. Impact/discussion SFT are tumours of fibroblast differentiation that can be benign or malignant. The retroperitoneum is a very rare site of origin for SFT, and most of these grow to large sizes before diagnosis. This case illustrates the aggressive, rapidly growing nature of these tumours, the challenges of diagnosing and treating them, as well as myriad complications due to mass effect. Based on current literature, most SFT are benign, however, as our case demonstrates, it is essential to assess for high-risk features on biopsy and perform serial imaging and close follow up to adequately manage recurrent disease. Its high recurrence rates and potential for metastatic spread often complicates prognosis and treatment. Due to the tumor’s aggressive nature, palliative care, alongside ongoing chemotherapy, is crucial for managing symptoms and improving quality of life. This report underscores the importance of a multidisciplinary approach in managing recurrent spindle cell sarcomas in the pelvis.

Comments

American College of Physicians Michigan Chapter and Society of Hospital Medicine Michigan Chapter Resident and Medical Students Day, May 2, 2025, Troy, MI

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