Ureteral intussusception associated with a fibroepithelial polyp: a case report

    Ureteral intussusception associated with a fibroepithelial polyp: A case report Kunihito Suzuki, Kazuhiro Saito, Nobutaka Yoshimura, Yoshio Ohno, Jun Nakashima, Hisashi Oshiro, Soichi Akata, Masaaki Tachibana, Koichi Tokuuye PII: DOI: Reference:

S0899-7071(15)00121-7 doi: 10.1016/j.clinimag.2015.05.009 JCT 7836

To appear in:

Journal of Clinical Imaging

Received date: Revised date: Accepted date:

4 February 2015 27 April 2015 13 May 2015

Please cite this article as: Suzuki Kunihito, Saito Kazuhiro, Yoshimura Nobutaka, Ohno Yoshio, Nakashima Jun, Oshiro Hisashi, Akata Soichi, Tachibana Masaaki, Tokuuye Koichi, Ureteral intussusception associated with a fibroepithelial polyp: A case report, Journal of Clinical Imaging (2015), doi: 10.1016/j.clinimag.2015.05.009

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Ureteral intussusception associated with a fibroepithelial polyp:

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A case report

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Kunihito Suzuki1, Kazuhiro Saito1, Nobutaka Yoshimura1, Yoshio Ohno2, Jun Nakashima2, Hisashi Oshiro3, Soichi Akata1, Masaaki Tachibana2, Koichi Tokuuye1 1. Department of Radiology, Tokyo Medical University

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2. Department of Urology, Tokyo Medical University 3. Department of Diagnostic Pathology, Tokyo Medical University Corresponding author: K. Saito 6-7-1 Nishishinjuku, Shinjuku-ku, Tokyo 160-0023, Japan Tel.: +81-3-3342-6111 E-mail: [email protected] Running title: Ureteral intussusception associated with a fibroepithelial polyp

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Key words: Ureteral intussusception, Fibroepithelial polyp, MDCT, MRI

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The authors have no conflict of interest to report.

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Abstract

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We present a case of a 67-year-old man with intussusception of the right ureter associated with a fibroepithelial polyp. The concentric sign and line sign are

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characteristic radiological findings in intussusception and these findings could be seen

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in the present case. Although this entity is rare, its radiological findings are specific. Multi-detector row CT and its multi-planar reconstruction make the diagnosis feasible,

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although the qualitative diagnosis of the tumor was difficult.

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Ureteral intussusception is a rare disease in which the proximal ureteral wall

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prolapses into the distal ureter. The probable cause of this entity in our case was the presence of a tumor and the weakness of fixation of the ureteral wall to the surrounding

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connective tissue. This led the proximal ureter to intussuscept into the distal ureter

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together with the tumor. Sometimes, ureteral intussusception is complicated by ureteral ischemia. Therefore, early diagnosis and treatment of a ureteral intussusception accompanied with a tumor is important.

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Fortunately, ureteral intussusception shows characteristic radiological findings.

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Multi-planar reconstruction from multi-detector row CT (MDCT) can show the detail [1,

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2]. Apparently there are few reports indicating the utility of MDCT for diagnosis of ureteral intussusception.

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We report a case of ureteral intussusception associated with a ureteral

fibroepithelial polyp (UFP) that was diagnosed preoperatively by MDCT.

Case report A 67-year-old man came to our hospital because of asymptomatic hematuria. The serological examination results were normal and the urine cytology was negative for malignancy. An excretory urogram (IVU) showed a right proximal ureteral filling

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defect with a distal dilated ureteral lumen and a slight dilation of the upper urinary tract

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and renal pelvis (Fig. 1). Contrast enhanced-CT on excretory phase showed a concentric three-layered structure (concentric sign) in the dilated ureter (Fig. 2). A multi-planar

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reconstruction image obtained by contrast enhanced-CT on excretory phase showed a

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filling defect with a dilated distal ureteral lumen, corresponding to the IVU finding. A linear contrast in the lumen of the invaginated proximal ureter (line sign) is a feature of the ureteral intussusception in a multi-planar reconstruction image (Fig. 3). In addition,

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by using multi-planar reconstruction imaging it was possible to visualize the associated

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ureteral tumor. In MR imaging, the tumor appeared as a T2-hyperintense and

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T1-isointense filling defect within the dilated lower ureter. A gadolinium contrast-enhanced image showed enhancement of the tumor (Fig. 4). From these

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imaging findings, the pathological condition was diagnosed as ureteral intussusception associated with tumor. The biopsy of the tumor was performed using transurethral ureteroscopy; the specimen was negative for malignancy. Subsequent observation was performed. There were no changes in CT findings for three months after the initial CT evaluation. Finally, a right ureteral partial resection was performed. The operation revealed that the ureteral intussusception developed because the proximal ureter together with the tumor entered the distal dilated ureter. The tumor was classified as a

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ureteral fibroepithelial polyp pathologically; its length was 37 mm. The excised

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recurrence was observed during the one year follow-up.

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specimen had no ischemic region and was negative for malignancy. No sign of

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Discussion

Ureteral intussusception is a rare disease and only about 20 cases have been reported so far. Ureteral intussusception occurs in the antegrade direction usually and is

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associated with benign or malignant tumors. Its frequency is the same with both benign

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and malignant tumors. A few cases of iatrogenic retrograde intussusception have been

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reported. Hematuria, colicky pain, and ureteral dilatation are common symptoms [2]. The characteristic radiological findings are important clues to diagnose ureteral

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intussusception. IVU shows the bell-shaped filling defect in the dilatated ureter [3]. This sign corresponds to the excretory contrast media in the ureteral lumen of the intussuscepted segment. The same sign can be seen in multi-planar reconstruction CT images on excretory phase. In particular, a linear contrast in the lumen of the invaginated proximal-ureter that is rendered by multi-planar reconstruction is called the “line sign”; it is characteristic of the disease [1, 2]. The “V-shaped configuration” and “stalk of corn appearance” are also characteristic signs in coronal or sagittal

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multi-planar reconstruction CT images [2]. The former sign represents abrupt

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terminating contrast-filled dilated intussusceptum. The latter sign represents proximal dilated intussusceptum containing excreted contrast media and excreted contrast media

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trapped in the intussuscipiens. Another characteristic sign on axial CT on excretory

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phase is the “concentric sign” (also referred to as the “target sign” or “bull’s-eye appearance”). The hyperdense center area and outer zone correspond to the proximal dilated intussusceptum and the intussuscipiens filled with excreted contrast media,

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respectively [2]. Therefore, the multi-planar reconstruction CT images are important in

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addition to axial CT to know the disease morphology.

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A fibroepithelial polyp led to intussusception in this case. They are rare entities and consist of fibrous and vascular tissue with normal transitional epithelium. They are

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commonly located in the proximal ureter and are seen in both adults and children. Their size is variable with a range of 1 to 12 cm in greatest dimension [2, 4]. CT findings of fibroepithelial polyps are non-specific. A blood clot, ascariasis, and a foreign body may show similar findings [5]. Furthermore, ureteral tumors are usually malignant. Although accurate diagnosis is important, there are limitations [5, 6]. MR findings of the fibroepithelial polyp appeared as a T2-hyperintense and T1-isointense filling defect within the dilated lower ureter. Gadolinium contrast-enhanced images reveal

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enhancement of the fibroepithelial polyp [7]. In this case, we could diagnose the ureteral

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intussusception and the associated tumor. However, accurate qualitative diagnosis could not be achieved by radiological findings (benign vs malignant).

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We performed the biopsy of the tumor by transurethral ureteroscopy; although

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malignant cells were not detected, malignancy could not be ruled out and the definitive diagnosis could not be obtained. We observed for a three month period and the size of the tumor did not change during the follow-up period; furthermore, hydronephrosis was

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not observed. This indicated incomplete obstruction of the ureter. Surgery is usually

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recommended for the prevention of ischemia in ureteral intussusception; however, we

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did not notice the onset of ureteral ischemia. Finally, we decided on surgical intervention because the presence of malignancy was not ruled out completely by

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biopsy alone.

In conclusion, ureteral intussusception caused by a tumor shows specific

radiological findings on CT, including multi-planar reconstruction images; therefore, its diagnosis is possible. However, qualitative diagnosis of the associated tumors is still difficult.

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antegrade intussusception. Urol Radiol, 1979. 1(1): p. 63-5. Wang, Z.J., M.V. Meng, B.M. Yeh, and R.B. Goldstein, Ureteral fibroepithelial polyp.

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tract. Singapore Med J, 2011. 52(3): p. e45-7.

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Figure legends

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Fig. 1

Excretory urogram. The “line sign” which indicates the contrast material in the

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distal dilated ureteral lumen is also shown.

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invaginated ureteral lumen within the intussuscepted ureter is shown (arrows). The

Fig. 2

Contrast enhanced computed tomography, excretory phase, axial plane.

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Three-layered structure of concentric circles is observed in the dilated ureter. This

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characteristic sign is the “concentric sign”. The hyperdense center area and outer zone

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correspond to the proximal dilated intussusceptum and the intussuscipiens filled with

Fig. 3

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excreted contrast media, respectively.

Contrast enhanced computed tomography, excretory phase, oblique sagittal

plane. Multi-planar reconstruction image shows a right ureteral filling defect in the dilatated ureteral lumen. A linear contrast in the lumen of the invaginated proximal ureter (line sign) is observed. A tumor was suspected at the tip (arrow). Fig. 4 Contrast enhanced magnetic resonance image, equilibrium phase, coronal plane.

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Gd-DTPA enhanced T1-weighted image shows the tumor enhancement (arrow).

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