COW-2019-38

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1. Ureteral endometriosis

Photomicrographs show normal ureteral urothelial mucosa with multiple glands within the muscularis propria. The glands are lined by bland pseudostratified nuclei and are surrounded by loose stroma composed of uniform cells with occasional hemosiderin laden macrophages.
The presence of glandular lesions within the ureteral wall, especially the muscularis propria, should prompt consideration of a cancer diagnosis, including urothelial carcinoma with glandular differentiation and primary and metastatic adenocarcinoma. Adenocarcinoma invariably has some degree of nuclear atypia and may exhibit a stromal desmoplastic response. Other benign glandular lesions, including ureteritis glandularis and Mullerinosis, should be included in the differential diagnosis. Ureteritis glandularis is a reactive lesion which is almost always seen with florid von Brunn nests and ureteritis cystica.
Mullerinosis refers to the presence of ectopic Müllerian tissue, including endocervical, endometrial and endosalpingeal, outside the uterus. Endometriosis involving the urinary tract occurs in approximately 1% of women with endometriosis, with 84% of cases occurring in the bladder and 15% of cases occurring in the ureters. In rare cases, it can involve the urethra and kidneys (1%). In women with deep infiltrating endometriosis, ureteral involvement can be seen in up to 53% of cases. The diagnosis relies on identification of at least two of the three components: endometrial glands, endometrial stromal cells, or recent or old hemorrhage. The main complication is ureteral compression with hydronephrosis and resulting decreased kidney function.
Other structures of Mullerian embryonic origin, including endosalpinx and endocervix, can rarely be found ectopically and together with endometriosis are termed Mullerinosis. These lesions tend to occur in older post-menopausal women, and may be related to pelvic surgery (Cesarian section and hysterectomy). Muscularis propria involvement by glandular lesions therefore does not necessarily imply malignancy, and benign metaplastic tissue or structures of embryologic origin should be considered.

Batt RE, Smith RA, Buck Louis GM, et al. Müllerianosis.
Histol Histopathol. 2007;22(10):1161-1166.

Hu Z, Li P, Liu Q, et al. Ureteral endometriosis in patients with deep infiltrating endometriosis: characteristics and management from a single-center retrospective study.
Arch Gynecol Obstet. 2019;300(4):967-973.

Habiba M, Brosens I, Benagiano G. Müllerianosis, Endocervicosis, and Endosalpingiosis of the Urinary Tract: A Literature Review.
Reprod Sci Thousand Oaks Calif. 2018;25(12):1607-1618.

Raimondo D, Mabrouk M, Zannoni L, et al. Severe ureteral endometriosis: frequency and risk factors.
J Obstet Gynaecol J Inst Obstet Gynaecol. 2018;38(2):257-260.

Alicia Dessain
Elizabeth Genega
Ming Zhou
Tufts Medical Center, Boston, MA
adessain@tuftsmedicalcenter.org

Ureter

Ureter, endometriosis, glandular lesions