A 41-year-old man presented with severe lower abdominal pain lasting for several weeks and increasing after meals. Neither physical nor per rectum examinations showed any abnormalities. Ultrasound revealed a pathologic, richly vascularized mass adjacent to the back wall of the bladder. The patient was referred for comprehensive diagnostic workup including contrast-enhanced computed tomography and magnetic resonance imaging of the abdomen and the pelvis. Imaging examinations disclosed a tumor measuring 69 mm × 78 mm × 62 mm located anteriorly from the rectum, posteriorly to the bladder, and superiorly to the prostate (Figure 1A–1C). The lesion was richly vascularized with inflow originating from the inferior mesenteric artery, and outflow draining to the inferior mesenteric vein (Figure 1D and 1E). Additionally, cystoscopy and colonoscopy were performed, both of which were unremarkable. Due to the rich vascularization and high risk of bleeding a biopsy was not performed. The patient was referred to the hospital where interventional radiology procedures were available. Based on the above findings, a decision on surgical resection after endovascular embolization was made.

Figure 1. A, B – computed tomography scan of the abdomen and the pelvis with contrast; a 60 mm × 70 mm × 78 mm tumor is visible anteriorly and left laterally from the upper rectum, in close proximity to the rectum, behind the bladder (asterisk), with strong contrast enhancement in the venous phase. The left side of the lesion shows areas of plaque, with nonenhancement (arrow); C–E – magnetic resonance imaging scan of the pelvis (C – T2-weighted image, D – T2 contrast-enhanced, fat saturated image, E – diffusion-weighted image): a richly vascularized lesion is visible (asterisk), with strong contrast enhancement and several areas of fluid density visible at its periphery (arrow). The lesion is surrounded by several wide, tortuous arterial and venous vessels that branch into it, diverging from the inferior mesenteric artery. F, G – angiography before embolization of the vessels supplying the tumor, showing rich vascularization of the lesion; H – angiography after embolization revealed the exclusion of the lesion from the bloodstream and maintenance of proper intestinal vascularity.

The procedure was performed from the femoral access using the Seldinger method. A Sim 2 catheter was used to cannulate the inferior mesenteric artery, and a Progreat microcatheter was used to selectively cannulate the arteries supplying the lesion (Figure 1F and 1G). The vessels were embolized using a mixture of a glue and lipiodol (20%). Control angiography showed complete occlusion of the feeding arteries with preserved blood flow to the branches supplying the bowel and the rectum (Figure 1H).

After the endovascular treatment, the patient underwent a surgery during which an exophytic rectal tumor was found growing from the serous layer of the intestine without clear separation from the rectal wall. Due to the lack of histological data from the biopsy prior to the resection, the patient underwent an anterior rectal resection with a total mesocolic excision of the vessels and lymphatic system. Histologic examination revealed a solitary fibrous tumor (SFT) with a low mitotic index, without infiltration and changes in 14 examined lymph nodes.

SFT is a rare neoplasm of a mesenchymal origin, accounting for about 2% of soft tissue tumors.1 The most common location for these tumors is the pleura. They occur less frequently in the abdominal cavity and their presence is evidenced by the mass effect caused by the tumor enlargement.2 Current data indicate a lack of proven effectiveness of radiotherapy and chemotherapy,3 and the only curative method is a surgical removal.4

Two months after the surgery, colonoscopy was performed, confirming proper intestinal anastomosis. The patient reports relief from symptoms and improvement in quality of life.

This case indicates that despite several unfavorable factors (rich vascularization precluding the biopsy, high intraoperative risk of bleeding), a complete and safe resection is feasible when adjuvant preoperative embolization is performed. Prompt referral of such patients to tertiary centers with interventional radiology departments is a key factor to successful treatment.