Endometrioid adenocarcinoma with squamous differentiation arising from ureteral endometriosis in a patient with no history of gonadal endometriosis.
BACKGROUND
Malignant transformation may occur in up to 1% of women with endometriosis and only 20% of these cases occur at extragonadal pelvic sites. Similarly, urinary tract endometriosis is rare and occurs in only 1% of all endometriotic lesions.


METHODS
An endometrioid carcinoma with squamous differentiation arising from periureteral endometriosis presented as a pelvic mass encasing the right ureter. The patient had a history of total hysterectomy and bilateral salpingo-oopherectomy 8 years earlier because of bilateral serous benign cysts with right hemorrhagic corpus luteum and uterine fibroids, and has since been under unopposed estrogen replacement therapy for 5 years.


CONCLUSIONS
This is the second case of a malignancy arising in endometriosis presenting as an obstructive ureteral mass and the first case of a patient with this condition whose endometriosis is not consistent with a gonadal origin. An analysis of the case and related literature is presented together with the discussion of possible pathogenetic mechanisms.
Salerno
M G
MG
Division of Gynecologic Oncology, Department of Surgical Pathology, Catholic University of Sacred Heart, Rome, Italy.
Masciullo
V
V
Naldini
A
A
Zannoni
G F
GF
Vellone
V
V
Scambia
G
G
D018269:Carcinoma, Endometrioid / Q000473:pathology*; D002294:Carcinoma, Squamous Cell / Q000473:pathology*; D002471:Cell Transformation, Neoplastic / Q000473:pathology; D004715:Endometriosis / Q000473:pathology*; D005260:Female; D006801:Humans; D007044:Hysterectomy; D008875:Middle Aged; D014513:Ureter / Q000473:pathology; D014516:Ureteral Neoplasms / Q000473:pathology*