Renal Endometriosis Mimicking a Malignancy—a Rare Case of Reno-Mullerian Fusion?

Diarmuid O’Connor,Gerard O’Sullivan,Kilian Walsh,Kevin Gerard Byrnes,Teresa Mchale

doi:10.1007/s42399-021-01001-3

Diarmuid O’Connor, Gerard O’Sullivan + Show 3 more

Open Access

https://doi.org/10.1007/s42399-021-01001-3

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Abstract

Endometriosis is a common gynaecological condition characterised by ectopic endometrial tissue growth beyond the uterine cavity. Urinary tract endometriosis represents only 1.2% of all cases, with renal endometriosis accounting for less than 1% of urinary tract involvement. An asymptomatic, 49-year-old, perimenopausal Irish female was found to have an incidental mass at the upper pole of the right kidney on imaging studies. Histological analysis was recommended to outrule a renal malignancy and an open radical nephrectomy was performed following multidisciplinary input. Histological analysis surprisingly revealed the presence of endometriosis and endosalpingiosis, accompanied by a significant smooth muscle component, which mimicked a renal neoplasm. The aetiology of renal endometriosis remains unclear. However, given the lack of a history of endometriosis and the absence of other foci of disease in this patient, together with the smooth muscle predominant phenotype, this may represent a case of reno-mullerian fusion or endometrial displacement during gestational development.

Highlights

Endometriosis is a common gynaecological condition characterised by ectopic endometrial tissue growth beyond the uterine cavity [1]
Several case studies have identified the diagnostic difficulty posed by renal endometriosis, in its differentiation from a neoplasm
Endometriotic lesions with a prominent smooth muscle component may give rise to a significant mass effect, which can mimic a malignancy on imaging studies

Summary

Introduction

Endometriosis is a common gynaecological condition characterised by ectopic endometrial tissue growth beyond the uterine cavity [1]. Histological analysis surprisingly revealed the presence of endometriosis and endosalpingiosis, accompanied by a significant smooth muscle component, which mimicked a renal neoplasm. Given the lack of a history of endometriosis and the absence of other foci of disease in this patient, together with the smooth muscle predominant phenotype, this may represent a case of renomullerian fusion or endometrial displacement during gestational development.

Results

Conclusion