{"paper_id":"ce0f8233-d180-488b-af1b-52d45ae07693","body_text":"Basiri et al. Afr J Urol           (2021) 27:84  \nhttps://doi.org/10.1186/s12301-021-00186-2\nCASE REPORTS\nLaparoscopic Resection of Renal \nCapsular Endometriosis in a Woman \nwith Menstrual-Related Flank Pain: Case Report\nAbbas Basiri, Iman Ghanaat and Hamidreza Akbari Gilani*  \nAbstract \nBackground: Although involvement of the urinary system is not uncommon, endometriosis in the kidneys is rare. To \ndate, laparoscopic partial nephrectomy has been the preferred approach for managing renal endometriosis. Here, we \nreport for the first time the results of laparoscopic removal of a renal capsular endometriosis in a malrotated kidney in \nan attempt to save the whole kidney parenchyma, in terms of feasibility and safety.\nCase presentation: A 37-year-old female presented with periodic right flank pain associated with her menstrual \ncycle. On imaging, a malrotated right kidney and a hypodense irregular-shaped lesion measuring 30 * 20 * 15 mm \nwere seen in the superior portion of the right perinephric space. Histologic evaluation of the ultrasound-guided \nbiopsy was consistent with renal capsular endometriosis. The patient underwent laparoscopic surgery to remove the \ncapsular mass while preserving the normal renal parenchyma. Pathological examination of the biopsy obtained dur-\ning surgery was in favor of renal endometriosis. At 6-month follow-up, the patient’s pain had completely disappeared \nand no complications had occurred. In addition, imaging did not show any remarkable recurrence.\nConclusion: Renal endometriosis should be strongly considered as a differential diagnosis in female patients with a \nrenal capsular mass and exacerbation of flank pain during menstruation. Based on our experience, with preoperative \nneedle biopsy and clearing the pathology, laparoscopic removal of the mass in spite of renal anatomic abnormality is \nfeasible and safe and thus could be considered as a possible treatment option.\nKeywords: Endometriosis, Malrotated kidney, Laparoscopy, Renal capsule\n© The Author(s) 2021. This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, \nadaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and \nthe source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material \nin this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material \nis not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the \npermitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http:// creat iveco \nmmons. org/ licen ses/ by/4. 0/.\n1  Background\nEndometriosis is characterized by the abnormal ectopic \ngrowth of endometrial tissue outside the uterus, most \ncommonly in the pelvic cavity [1]. Extrapelvic sites such \nas the gastrointestinal tract and the urinary system might \nalso be affected less frequently [2–4]. Signs and symp -\ntoms vary greatly depending on the site of involvement, \nbut the association of symptoms with menstrual cycles \nraises the clinical suspicion of endometriosis. Although \nimaging aids in the initial diagnosis, the final diagnosis \nmust be confirmed through histologic examination [5]. \nSince medical treatment is associated with recurrence of \nsymptoms, surgery is the standard of choice for manag -\ning renal endometriosis, unless in special cases [6, 7].\nHerein, we report a 37-year-old woman with right flank \npain and a malrotated right kidney who was found to be \na case of renal endometriosis following further evalua -\ntion. Although laparoscopic partial nephrectomy is the \npreferred treatment in this patient, we performed lapa -\nroscopic removal of the renal capsular endometriosis to \npreserve kidney function. This study aims to discuss the \nfeasibility and complications of this treatment modality.\nOpen Access\nAfrican Journal of Urology\n*Correspondence:  hamidrezaakbari1261@gmail.com\nDepartments of Kidney Transplantation and Urology, Shahid Labbafinejad \nMedical Center, Urology and Nephrology Research Center, Tehran, No \n103, 9th Boustan, Pastaran, Tehran 1666697751, Iran\n\nPage 2 of 5Basiri et al. Afr J Urol           (2021) 27:84 \n2  Case presentation\nIn June 2019, a 37-year-old female was referred to our \ncenter with menstrual-related periodic right flank pain. \nShe did not report any significant past medical or sur -\ngical history and was normal on physical examination. \nShe had given birth to two children via normal delivery \nmany years ago. Routine laboratory tests were normal. \nUltrasonic assessment (US) showed mild hydronephro -\nsis of the right kidney. Further evaluation with computed \ntomography (CT) revealed a malrotated right kidney \nwith mild hydronephrosis, but no obstruction was seen \non contrast-enhanced imaging. Moreover, a hypodense \nirregular-shaped lesion, probably originating from the \nrenal capsule, was noted in the superior portion of the \nright perinephric space causing mild pressure effect on \nthe right kidney. The size of the lesion measured approxi-\nmately 30 * 20 * 15  mm (Figs.  1a, b and  2). In the next \nstep, US-guided percutaneous renal mass biopsy was \nperformed and histologic examination revealed loosing \nbenign endometrial growth and fibroconnective stroma \nin favor of endometriosis. Following confirmation of the \ndiagnosis, we decided to enucleate the renal capsular \nmass, laparoscopically.\nAfter placing the patient in right flank position and \ninserting four trocars, the malrotated right kidney was \nexposed transperitoneally (Fig.  3). Subsequent to find -\ning the exact site of the mass, laparoscopic enucleation \nand complete removal of the renal capsular mass were \nperformed with the preservation of normal renal paren -\nchyma. No significant bleeding occurred during this pro -\ncess, and the obtained specimen was eventually sent for \npathologic evaluation (Fig. 4).\nOn pathological examination, a 60 * 25 * 10  mm mass \n(Fig. 5) containing fibroadipose tissue along with clusters \nof endometrial glands and stroma (endometrial nests) \nand hemorrhage was seen which was compatible with the \ndiagnosis of renal capsular endometriosis (Figs. 6, 7).\nAt 6-month follow-up, the patient did not complain \nof any complications and her pain had completely dis -\nappeared. Also, imaging study at 4 months after surgery \nshowed no remarkable recurrence of the mass (Fig. 8).\n3  Discussion\nEndometriosis or extra-uterine endometrial growth \nmight occur in the urinary system, mainly affect -\ning the bladder and ureters and rarely the kidneys. The \nmedian age of diagnosing extrapelvic endometriosis is \n34–40 years [8]. The first published report of renal endo -\nmetriosis dates back to the 1950s in which metaplasia \nwas thought to be the possible etiology [9–11].\nRenal endometriosis might be associated with pain and \nhematuria [13, 14, 17–19], or it could be symptomless \nFig. 1 a Abdominopelvic CT showing a heterogeneous mass (black \narrow) with pressure effect on the upper pole of the right kidney \n(coronal view). b. Abdominopelvic CT showing a heterogeneous \nmass (black arrow) with pressure effect on the upper pole of the right \nkidney (axial view)\nFig. 2 Abdominopelvic CT showing malrotated right kidney (black \nstar) and anteriorly oriented right renal pelvis\n\nPage 3 of 5\nBasiri et al. Afr J Urol           (2021) 27:84 \n \n[15, 16]. On imaging, it presents either as a mass [14–17], \ncomplicated cyst [15–18] or a subcapsular hematoma \n[19]. The case described here presented with a capsular \nmass without any abnormality in the renal parenchyma \nexcept for fat stranding around the mass in the per -\ninephric space.\nRegarding the surgical management of such patients, \ndifferent approaches such as open, laparoscopic, and \nrobotic-assisted partial nephrectomy have been utilized \nso far [5 , 12, 14, 19]. This is the first report of laparo -\nscopic removal of a renal capsular endometriosis mass \nin an attempt to save the whole kidney.\nDirim et al. in Fertility and Sterility in 2009 reported \na 15 cm left kidney subcapsular hematoma, which, after \npartial drainage by percutaneous catheter, was explored \nby open flank incision. The final pathology was renal \ncapsular endometriosis [5 ].\nElham Arabzadeh et al. in American Journal of Clini -\ncal Pathology in 2018 reported laparoscopic partial \nnephrectomy of 3  cm enhancing left renal mass with \npreoperative suspicion of RCC. The final pathology was \nrenal endometriosis. The authors concluded that in the \nappropriate clinical setting and suspicion of renal endo -\nmetriosis, needle biopsy may prevent overtreatment \nand lead to preservation of renal normal parenchyma \n[12].\nFig. 3 Malrotated right kidney (black star). The arrow shows the \nanteriorly oriented renal pelvis and ureter\nFig. 4 Laparoscopic resection of the capsular mass with a safe \nmargin. The black star shows normal renal parenchyma, and the \narrow shows the mass being resected\nFig. 5 Macroscopic (gross) view of the capsular mass\nFig. 6 Microscopic view of the specimen (Regions 1 and 2 show \nthe endometrial nests and fibroadipose tissue of the renal capsule, \nrespectively)\nFig. 7 Microscopic view of the specimen (Regions 1, 2, 3, 4, and 5 \nshow fibroadipose tissue, stroma, hemorrhage, endometrial nest, and \nthe renal capsule, respectively)\n\nPage 4 of 5Basiri et al. Afr J Urol           (2021) 27:84 \nBadri et  al. in Journal of Endourology Case Report \nin 2018 reported robotic partial nephrectomy of 3  cm \nenhancing left renal mass, which postoperatively proved \nto be endometriosis [14].\nGiambelluca et al. in Chir in 2017 reported two cases \nof incidentally found asymptomatic renal endometrio -\nsis, proved by needle biopsy. As in both patients, renal \nlesions were asymptomatic and unchanged on subse -\nquent imaging examination, and no therapy was needed \n[15].\nTo the best of our knowledge, this is the first case \nreport of renal endometriosis with menstrual-related \npain, diagnosed preoperatively, with attempt to remove \njust the endometrial mass and save the whole kidney. \nPrevious articles had considered open or laparoscopic \npartial nephrectomy, mainly because there was preop -\nerative probability of malignancy. Performing fine needle \naspiration or biopsy before definite intervention helps the \nphysician to decide about the best choice of treatment \nby ruling out other differential diagnoses [20]. We per -\nformed US-guided biopsy for our patient before surgery \nwhich was consistent with renal capsular endometriosis. \nThis provided us with a better outlook on the patient’s \nnature of disease and allowed us to select a minimally \ninvasive modality, confidently.\nNevertheless, this individual experience is not expand -\nable to different types of renal capsular endometriosis \nor various renal anatomic abnormalities. Thus, a larger \nnumber of cases are required for better concluding \nresults.\n4  Conclusion\nIn this paper, we have reported for the first time the lapa-\nroscopic removal of a histologically documented isolated \nrenal capsular endometriosis in a malrotated kidney. \nWe considered saving the whole kidney, which was not \nassociated with any early or late complications. Based \non our experience in this patient, we recommend mini -\nmally invasive treatment modalities as a suitable option \nfor renal endometriosis in the presence of renal anatomic \nabnormality. However, further experience of managing \nsimilar patients with this approach is warranted to reach \na conclusion regarding its safety and feasibility.\nAbbreviations\nRCC : Renal cell carcinoma; CT: Computerized tomography.\nAcknowledgements\nWe acknowledge the pathology ward of Labbafinejad medical center for their \nhelp and support in preparing this case report.\nFig. 8 Abdominopelvic CT at 4 months postoperative visit, showing no recurrence at the site of previous right renal capsular mass\n\nPage 5 of 5\nBasiri et al. Afr J Urol           (2021) 27:84 \n \nAuthors’ contributions\nAB has made substantial contribution in treatment plan and performance, \nediting the final and modified version of the manuscript. IG has made sub-\nstantial contribution in treatment of the patient and writing of initial version of \nthe manuscript. HAG has made substantial contribution in treatment plan and \nperformance, editing the final and modified versions of the manuscript. All \nthe authors have participated in patient treatment and writing the article. All \nauthors read and approved the final manuscript.\nFunding\nNot applicable.\nAvailability of data and materials\nPatient’s medical files and operation video are available in Labbafinejad medi-\ncal center.\nDeclarations\nEthics approval and consent to participate\nThe treatment procedure was according to ethical guidelines of our center. \nWe obtained written informed consent for participation from the participant \npatient.\nConsent for publication\nWritten Informed consent for publication of case report was obtained from \nthe participant patient.\nCompeting interests\nThere was no funding for the study and no conflicts of interest to disclose.\nReceived: 13 February 2021   Accepted: 12 June 2021\nReferences\n 1. Signorile PG, Baldi A (2010) Endometriosis: new concepts in the patho-\ngenesis. Int J Biochem Cell Biol 42(6):778–780\n 2. Moore JG, Hibbard LT, Growdon WA, Schifrin BS (1979) Urinary tract endo-\nmetriosis: enigmas in diagnosis and management. 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