The Diagnosis and Differential Diagnosis of Ureteral Fibroepithelial Polyps

Pathogenesis

The exact etiology of the polyps is not certain. Many theories have been proposed including congenital obstruction, trauma, irritation, infection, and allergic factors^[4]. Downs ^[5] speculated that fibroepithelial polyps originate from developmental defects of the urinary tract, while Kuppusami and Moors ^[6] attributed the pathogenesis to the absence of estrogen in the matrix and subsequent fibroepithelium transformation, Lou et al^[7]. have suggested that FEP polyps derive from congenital malformation, an etiology being the most frequently accepted.

Patients may either be completely asymptomatic or present with unrelated symptoms, suggesting that the tumor cannot be related to a single origin. We believe that more than one factor is involved during the development of this disease.

Clinical symptoms

Clinical symptoms of fibroepithelial polyps frequently appear between the second and fourth decades of life, although the polyps can occur at any age ^[8]. Macksood et al^[9]. hold that fibroepithelial polyps are the most usual benign ureteral lesion in children. In adults, the majority of these tumors are seen in the upper ureter, at the ureteropelvic junction^[10]. There is no notable incidence difference between the left and right sides and no familial traits have been reported.

Flank pain and hematuria are the leading symptoms, but infection, urgent maturation, dysuria and urinary tract obstruction also occur as familiar symptoms. As some noted previously, cases remain completely asymptomatic for many years, until the development of hydronephrosis, which is related to the degree of obstruction of the ureter. Such was the patient's condition in our case.

In general, calcului can be found occasionally as a complication and will be not implanted into the urinary tract without growing obviously thick. However, FEP initiated by calcului are rarely found, having been reported in only one case^[11].

Clinical diagnosis

Diagnosis of FEP is not difficult, but misdiagnosis can occur because of a doctor's incomplete examination. If a laboratory examination reveals an upper urinary tract obstruction without the presence of a calculus, FEP should be primarily taken into considerasion. Most cases have complications of hydronephrosis. Banner and Pollack ^[12] considered radiology to be a suitable procedure, while Kim et al^[13]. preferred flexible ureter cystoscopy to be the best means. Typically, X-rays of FEP show a long thin filling defect. In our case, intravenous urography (IVU) revealed a filling defect in the ureter with a smooth and sharply demarcated outline. Of course, histological diagnosis confirmed the result. In general case, most FEP are long slender projections grossly with a smooth surface presenting as single or multiple villiform segment with a maximal length of 13 cm. In our case, a polyp of 7 cm long appeard. Some have claimed they can be long enough to enter into the bladder^[14]. Microscopically, FEP arise from the submusoca and are composed of a loose connective tissue core covered by a layer of normal urothelium. The central edematous stromal stalk contains collagen smooth muscle fibers, fibroblasts and acute and chronic inflammatory cells meet occasionally, even some irregular star-like polynucleated cells, which may cause misdiagnosis. The polyps are connected with the ureteral wall. They have a wider stalk and looser connective tissue compared to a papillary urothelial neoplasm, and a few acute and chronic inflammatory cells may be found.

Differential diagnosis

Treatment and prognosis

FEP are nonepithelial tumors that originate from mesodermal tissue of the ureteral wall. No reported cases of recurrence after local resection have been found in the literature. Many surgical approaches have been advanced for benign polyps. Low grade FEP can shrink by removing the obstruction and control of the infection. Because of their benign nature, surgical therapy should be limited and conservative if the kidney function is normal; otherwise, nephroureterectomy should be performed. On follow-up examinations at nine years after surgery, tumor recurrence and canceration were not detected^[15]. Recently, with the development of molecular pathology, a new suggestion has been posted: a follow-up examination has been recommended if P53 and (or) c-myc were positive immunohistochemically. These findings may indicate a malignancy potential^[15].