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CASE REPORT Table of Contents  
Ahead of print publication
Periureteral liposarcoma causes of hydroureter and hydronephrosis: An unpredictable diagnosis

1 Department of Medicine, School of Medicine, College of Medicine, Taipei Medical University, Xinyi District, Taiwan
2 Department of Obstetrics and Gynecology, Shuang Ho Hospital, Taipei Medical University, New Taipei City, Taiwan

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Date of Submission23-Mar-2022
Date of Decision17-Apr-2022
Date of Acceptance04-May-2022
Date of Web Publication16-Sep-2022


When obstructive lesions from the uterus or ovaries are suspected, patients with hydronephrosis are usually referred to a gynecologist. Here, a case of suspected endometriosis-related hydroureteronephrosis is reported. A 43-year-old woman with hydronephrosis was found to have a left distal periureteral tumor on the computerized tomography scan. Before the operation, the hydroureteronephrosis was suspected caused by the obstruction of ureter, related with ureteral endometriosis; however, the postoperative pathology revealed the diagnosis of retroperitoneal well-differentiated liposarcoma. When female patients have hydronephrosis, gynecologic causes should be considered. Both benign and malignant causes are needed to include when making differential diagnosis. Therefore, robot-assisted surgery is a feasible option because of its lower morbidity rate and more precise dissection of soft tissue than laparotomy in both benign and malignant retroperitoneal tumors.

Keywords: Case reports, endometriosis, hydronephrosis, liposarcoma, minimally invasive surgical procedures, retroperitoneal neoplasms, robotic surgical procedures,

How to cite this URL:
Lin TE, Wen KC, Lai HC, Chu LH. Periureteral liposarcoma causes of hydroureter and hydronephrosis: An unpredictable diagnosis. Gynecol Minim Invasive Ther [Epub ahead of print] [cited 2022 Oct 3]. Available from: https://www.e-gmit.com/preprintarticle.asp?id=356207

  Introduction Top

Hydronephrosis is most commonly caused by ureteral calculi, kidney stones, benign prostatic hyperplasia, narrowing of the ureters, neurogenic bladder, and cancers in or around the urinary tract. It is sometimes managed by a gynecologist when obstruction by a gynecologic organ is suspected. Common gynecologic conditions associated with hydronephrosis are cervical cancer, advanced uterine or ovarian cancer, and cystoceles with urinary retention. Urinary tract endometriosis is a rare but important differential diagnosis when adenomyosis or ovarian endometrioma is suspected through imaging workup.[1]

Liposarcomas are a group of rare cancer of the connective tissue that originates in fat cells, accounting for <1% of all malignant tumors but 50% of retroperitoneal soft-tissue sarcomas.[2] Herein, we present a case of retroperitoneal well-differentiated liposarcoma (WDLPS) that clinically mimicked pelvic endometriosis complicated with hydronephrosis.

  Case Report Top

A 43-year-old woman, with a body mass index of 23.59 kg/m^2, complained of gross hematuria for 3 weeks. Kidney–ureter–bladder radiography performed on presentation to the urological department revealed no stone-like lesions. Thereafter, a computed tomography (CT) scan with intravenous contrast was arranged for further evaluation, which showed severe left-sided hydronephrosis, a small left distal periureteral mass, bilateral adnexal cystic lesions, and adenomyosis with small myomas. No obvious intra-abdominal or retroperitoneal lymph node enlargement was noted. The radiology impression was left obstructive uropathy, suspected caused by left distal ureteral tumor [Figure 1]. Endometriosis-related adhesion and obstruction of the left ureter were suspected. The patient was referred to the gynecology department for further evaluation.
Figure 1: (a) Axial view showing left-sided hydroureter (yellow arrow) and the tumor (red arrow). (b) Coronal view showing the left periureteral tumor (red arrow), left-sided hydronephrosis (K) and uterine myomas (U), and a more anterior slice (c) showing hydroureter (yellow arrow)

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Pelvic examination revealed tightness of the left adnexal area with mild tenderness. Carcinoembryonic antigen and CA-125 were within the normal limits, and a pap smear showed normal findings. The signs and symptoms of endometriosis and pelvic vaginal ultrasound are data limitations. Under the suspicion of hydronephrosis caused by the ureteric endometriosis and uterine adenomyosis, a robotic resection of the left distal ureteral mass and supracervical hysterectomy was performed. Ureteric stent was also inserted to relieve the symptoms. However, no endometriosis-like cystic lesion or adhesions were found near the obstruction level of the left ureter. Instead, a 1.5-cm retroperitoneal lobulated solid mass was noted at the lower third of the ureter, causing narrowing of the ureteral lumen [Figure 2]. Double J stent was also inserted in the left ureter for drainage of hydronephrosis in the operation.
Figure 2: (a) No adhesion between the adnexa (arrow) and ureter. (b) Retroperitoneal tumor (arrow). (c) Hydroureter (white arrow) and periureteral tumor (yellow arrow). (d) The tumor (yellow arrow) was removed from left ureter (white arrow). (e) One area of ureteral stricture (arrow) remained

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In pathology, the specimen of the tumor fragment was grossly gray and soft, and it measured 2.6 cm × 2.2 cm × 1.4 cm. Microscopically, sections of the periureteral nodule showed fibroblastic proliferation composed of fibroblasts and fibrotic stroma. However, several atypical cells presented in the fibroblastic stroma and adjacent adipose tissue of periureteral soft tissue attracted the pathologist's attention. Additional immunohistochemical stains for MDM2 and CDK4 were performed, which revealed diffuse nuclear immunoreactivities. Amplifications of MDM2 and CDK4 were further confirmed through fluorescence in situ hybridization. The final pathological report revealed that the tumor was a WDLPS.

The patient was followed up at outpatient clinics without adjuvant chemotherapy. A magnetic resonance imaging (MRI) scan was arranged 3 months after the surgery, which revealed no obvious local tumor recurrence.

  Discussion Top

Numerous mechanic defects can lead to hydronephrosis, such as calculi, inflammation, intrinsic or extrinsic tumors, and the pregnant uterus. Many gynecologic causes of hydronephrosis have been reported, including endometriosis, tumor compression, and advanced pelvic organ prolapse.[3] Endometriosis is an important differential diagnosis causing hydronephrosis when the obstruction is at the distal ureter.[4] Hydronephrosis may occur as a result of the involvement of intrinsic ureteric endometriosis or extrinsic compression by endometrioma.[1] However, the preoperative diagnosis of ureteral endometriosis is equivocal because more than half of the patients lack specific symptoms. Women with hydronephrosis, hematuria, infertility, or pelvic pain but without evidence of stones or malignant pelvic tumor should be evaluated for ureteral endometriosis. Because imaging studies such as CT or MRI do not reveal specific features for ureteral endometriosis, the gold standard for diagnosis remains ureteroscopy or laparoscopy with pathologic examination.[4]

The diagnosis and surgical approach for small-sized retroperitoneal WDLPS have not been fully discussed. Most published case reports of WDLPS have discussed the large and obvious retroperitoneal lipomatous tumors, to which CT scans are sensitive for diagnosis because large lipomatous tumors consist only of well-differentiated fat. Nevertheless, because the lesions are small and unrecognizable at first, early diagnosis of liposarcomas with imaging or by examining intraoperational gross appearance is challenging. Miwa et al. analyzed the diagnostic accuracies of histological grades of intraoperative pathologic diagnosis in patients with soft-tissue tumors. The results revealed that only four of seven cases with WDLPS showed an accurate histological grade on the frozen-section diagnosis.[5] Only one case of WDLPS was misdiagnosed as a benign adipocytic tumor; therefore, a frozen-section diagnosis may still provide an initial approach to differentiating malignant from benign adipocytic tumors.

To distinguish different types of liposarcomas and lipomas, postoperative molecular analysis is often required. Biomarkers such as MDM2, CDK4, and p16 are helpful in achieving the final diagnosis of WDLPS.[6] Because of the small size of retroperitoneal liposarcomas and unspecific symptoms and image findings for ureteral endometriosis, liposarcomas can be easily misdiagnosed preoperatively. On MRI, ureteral endometriosis can appear as a hypointense nodule with hyperintense foci on T1- and T2-weighted sequences. In some rare cases, ureteral endometriosis with adipose tissue within the mass could be easily confused with retroperitoneal liposarcoma.[7]

Consequently, considering the difficulties in achieving an accurate preoperative diagnosis, an appropriate surgical method is required to obtain better results in patients with benign or malignant lesions.

Laparoscopy is a widely used method for the management of ureteric endometriosis due to its clear visual system and high-power-density electrosurgical instruments. In a prospective study, 160 patients with deep infiltrating endometriosis (DIE) with ureteral, parametrial, and bowel involvement who underwent laparoscopic radical eradication or ureteroneocystostomy were included. Hydronephrosis was detected in 110 patients (68.7%), unilateral ureteral stenosis in 151 patients (94.3%), and bilateral stenosis in 9 patients.[8] Laparoscopic radical eradication and ureteroneocystostomy have been proven to be feasible, safe, and effective treatments for DIE and ureteral endometriosis. However, difficulties with intracorporeal suturing and a prolonged operative time for larger endometriotic nodules may pose a challenge in traditional laparoscopic surgery. Robot-assisted (RA) surgery is the possible solution for these challenges.

A retrospective study enrolled 164 women with DIE who underwent RA laparoscopy, including 115 cases with ureter and uterosacral ligament involvement. The overall reoperation rate was 1.8%, and the rate of laparotomy conversions was 0.6%. For patients with severe endometriosis with lesions infiltrating the retroperitoneum or pelvic organs, RA laparoscopy is a safe and feasible approach.[9]

Likewise, as mentioned in the treatment of ureteral endometrioses, RA laparoscopy also presents favorable surgical outcomes in the treatment of other retroperitoneal tumors. In a comparative retrospective study, a total of 88 patients with benign and malignant mesenchymal tumors were divided into three treatment groups, namely the RA method, laparoscopic approaches (LA), and the traditional open approach (TA). The mean blood loss was the same in the RA and LA groups, but it was 2.5-fold higher in the TA group. The postoperative length of stay and morbidity rate was also shorter and lower in the RA group than in the TA group. The conversion rate was significantly lower in the RA group (2.8%) than in the LA group (50%). Robotic surgery is safe and feasible for benign or malignant small retroperitoneal tumors, especially when the tumors are hard to reach or are located next to major vessels.[10]

Hydronephrosis has numerous causes, which makes correct diagnoses before or during the surgery difficult when the lesions are small. Therefore, a suitable approach to assessing different lesions is important. Minimal invasive surgery is a feasible option because of its lower mean blood loss and morbidity compared with traditional laparotomy for both benign and malignant retroperitoneal tumors. Delicate dissection and resection with RA surgery may be suitable and effective for rare subtypes like WDLPS from the retroperitoneum.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient has given her consent for her images and other clinical information to be reported in the journal. The patient understands that her name and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

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Conflicts of interest

There are no conflicts of interest.

  References Top

Smith IA, Cooper M. Management of ureteric endometriosis associated with hydronephrosis: An Australian case series of 13 patients. BMC Research Notes 2010;3:45.  Back to cited text no. 1
Matthyssens LE, Creytens D, Ceelen WP. Retroperitoneal liposarcoma: Current insights in diagnosis and treatment. Front Surg 2015;2:4.  Back to cited text no. 2
Hui SY, Chan SC, Lam SY, Lau TK, Chung KH. A prospective study on the prevalence of hydronephrosis in women with pelvic organ prolapse and their outcomes after treatment. Int Urogynecol J 2011;22:1529-34.  Back to cited text no. 3
Barra F, Scala C, Biscaldi E, Vellone VG, Ceccaroni M, Terrone C, et al. Ureteral endometriosis: A systematic review of epidemiology, pathogenesis, diagnosis, treatment, risk of malignant transformation and fertility. Hum Reprod Update 2018;24:710-30.  Back to cited text no. 4
Miwa S, Yamamoto N, Hayashi K, Takeuchi A, Igarashi K, Tada K, et al. Accuracy of histological grades from intraoperative frozen-section diagnoses of soft-tissue tumors. Int J Clin Oncol 2020;25:2158-65.  Back to cited text no. 5
Thway K, Flora R, Shah C, Olmos D, Fisher C. Diagnostic utility of p16, CDK4, and MDM2 as an immunohistochemical panel in distinguishing well-differentiated and dedifferentiated liposarcomas from other adipocytic tumors. Am J Surg Pathol 2012;36:462-9.  Back to cited text no. 6
Menon VM, Sharma A, Kamboj M, Pasricha S, Singh S, Venkatasubramanian M. Mass-forming deep infiltrating retroperitoneal endometriosis mimicking liposarcoma: A rare diagnosis. J Gynecol Surg 2020;36:361-4.  Back to cited text no. 7
Ceccaroni M, Ceccarello M, Caleffi G, Clarizia R, Scarperi S, Pastorello M, et al. Total laparoscopic ureteroneocystostomy for ureteral endometriosis: A single-center experience of 160 consecutive patients. J Minim Invasive Gynecol 2019;26:78-86.  Back to cited text no. 8
Collinet P, Leguevaque P, Neme RM, Cela V, Barton-Smith P, Hébert T, et al. Robot-assisted laparoscopy for deep infiltrating endometriosis: International multicentric retrospective study. Surg Endosc 2014;28:2474-9.  Back to cited text no. 9
Berelavichus S, Kriger A, Kaldarov A, Panteleev V, Raevskaya M. Robotic surgery in treatment of retroperitoneal tumors. Comparative single center study. J Robot Surg 2021;15:363-7.  Back to cited text no. 10

Correspondence Address:
Ling- Hui Chu,
Department of Obstetrics and Gynecology, Shuang Ho Hospital, Taipei Medical University, No. 291, Jhongjheng Road, Jhonghe Dist., New Taipei City 23561
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/gmit.gmit_29_22


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