Mesenteric Solitary Fibrous Tumor with High Risk for Aggressive Behavior: A Case Report.

A 64-year-old female presented to the emergency department (ED) with complaints of two days of intermittent fever and chills, progressively worsening back pain, and hematochezia. Initial evaluation and computer tomography (CT) imaging work up revealed a hypervascular and necrotic appearing pelvic mass, measuring 11.7 x 7.8 x 9.7 cm, closely associated with the inferior mesenteric vein (IMV) in conjunction with portal venous gas. Flexible sigmoidoscopy with biopsy was performed to identify the etiology of the lesion and revealed an ulcerated non-obstructing mass in the recto-sigmoid colon measuring 3 cm in length and involving 1/3 of lumen circumference with oozing present. Interventional radiology (IR) embolization of the feeding vessels was done pre-operatively due to high vascularity of the mass. Pathology of the mass was consistent with a malignant solitary fibrous tumor.