Retro vesical solitary fibrous tumor: A case report

Abstract

Solitary fibrous tumor (SFTs), initially described in the 1930s, are a group of rare heterogeneous tumors primarily located in the pleural area but can manifest in any site.This article focuses on the case of a patient with a localized retroperitoneal pubic tumor treated surgically, which demonstrates on one hand the heterogeneity of clinical manifestations, the limited diagnostic contribution of imaging, and on the other hand the histological diagnostic difficulty despite the recent contribution of immunohistochemistry. Management remains primarily surgical, to the detriment of other alternatives that have not yet shown encouraging results.

1 Introduction

Solitary fibrous tumors (SFTs) are a rare group of fibrotic mesenchymal neoplasms, with a yearly incidence of 1 new case per million people. ^, . Known for they low metastatic potential, ^, , SFTs can manifest anywhere in the body. . In this case report we describe a rare location of a SFT in the retroperitoneum.

2 Presentation of case

A 59-year-old patient with no medical or surgical history who has been complaining for six months of paroxysmal hypogastric pain, with a visual analog scale (VAS) of 2–3, associated with pollakiuria, urinary leakage due to urgency, and constipation. Otherwise, the patient does not report any notion of weight loss or deterioration of the general condition. A physical examination showed a mass occupying the whole of the sub-umbilical stage with solid consistency, painless, well-limited with sharp contours, motionless making at least 20 cm of major axis ( Fig. 1 ). Digital rectal examination, showed a small, non-suspect prostate without a bulging mass in the rectal lumen. The rest of the examination was without abnormalities. Blood tests showed moderate microcytic hypochromic anemia and hypoproteinemia. An heterogeneous sub-peritoneal mass with necrotic areas measuring 14 cm of long axis compressing the 2 ureters with a dilation of the renal cavities upstream is found on the CT scan, pushing the prostate and seminal vesicles down, the bladder forward, the sigmoid colon to the left, and the iliac vessels poster externally ( Fig. 2 ). Because of the size of this mass and the risk of non-contributory biopsies, it was preferred to perform surgery straight away. Intraoperative findings showed a sub-peritoneal mass surrounded by a capsule adherent to the iliac axes, promontory, and sacrum posteriorly repressing the rectum. The right ureter crosses the anterior mass encased in its capsule ( Figs. 3 and 4 ). Therefore excision of the mass was performed leaving a pseudo-capsule tightly attached to the rectum and presacral plexus with profuse bleeding (transfusion of 12 RBCs/10 CFP). The patient had uneventful postoperative care and was discharged as planned. Histologically, it was largely necrotic and hemorrhagic with a grayish white lobular appearance with focal cystic redistribution and extensive necrosis. Microscopic examination reveals spindle cell proliferation organized into short, microarray bundles. We found 5 mitoses per High Power Fields. The limits of excision are in places in contact with the tumor proliferation. Immunochemistry examination demonstrated an intense and diffuse labeling of the tumor cells with CD34. Therefore, the tumor was considered to be at high risk of recurrence and metastasis. No adjuvant therapy was given after the procedure and the patient remained asymptomatic. A postoperative CT scan was performed 6 months later, revealing locoregional pelvic recurrence treated with radiotherapy, showing a good local response.