a congenital anomaly syndrome including wilms ' tumor , aniridia , genitourinary anomalies and mental retardation ( wagr syndrome ) is a rare , sporadic genetic disorder characterized by a de novo deletion in the distal band of chromosome 11p13 ( 1 ) . wagr syndrome is often diagnosed when aniridia is clinically evident and a chromosomal analysis is performed . the incidence of wilms ' tumor in caucasians is 1/10,000 , and a previous study reported that 0.75% of patients with wilms ' tumor have wagr syndrome ( 2 ) ; thus , wagr syndrome is an extremely rare condition . we encountered a case where a pelvic tumor in a female patient with wagr syndrome was diagnosed as dysgerminoma . the tumor is considered to have developed from an ectopic ovary , which is defined as ovarian tissue found outside a normal ovary . an ectopic ovary is extremely rare , with an incidence of 1/93,000 ( 3 ) . in addition , reports of an ovarian tumor forming from an ectopic ovary are also rare ( 46 ) . the present case involved a 24-year - old nulliparous woman with a height of 159 cm , weight of 89 kg and bmi of 35.2 kg / m . aniridia at birth led to the diagnosis of wagr syndrome . at the age of 7 months , left nephrectomy and postoperative chemotherapy with vincristine and actinomycin d were performed to treat wilms ' tumor . at the age of 7 years , glaucoma surgery was performed . since the age of 20 years , the patient has been receiving oral medication at the department of pediatrics of our hospital to treat diabetes mellitus , hypertension and hyperuricemia . the patient was investigated at the department of pediatrics for oliguria , and her blood pressure was 220/130 mmhg . blood collected at the time was tested , revealing elevated levels of blood urea nitrogen ( bun ; 45 mg / dl ) and creatinine ( cr ; 5.4 mg / dl ) . blood test results upon admission revealed a white blood cell count of 6,100/l , hemoglobin ( hb ) level 10.7 g / dl , platelet count 279,000/l , aspartate aminotransferase level 21 u / l , alanine aminotransferase level 34 u / l , lactate dehydrogenase 162 u / l , total cholesterol 214 mg / dl , triglycerides 298 mg / dl , bun 45 mg / dl , cr 5.4 mg / dl , uric acid 7.3 mg / dl , na 144 meq / l , k 4.1 meq / l , cl 104 meq / l , ca 9.1 meq / l , blood glucose 101 mg / dl , hba1c 5.6% and c - reactive protein 2.52 mg / dl . a ct scan revealed a solid mass with a long axis of ~80 mm in the pelvis . there were signs of hydronephrosis in the right kidney due to ureteral compression by the mass , which was hypothesized to have caused postrenal failure . placement of a ureteral stent in the right ureter alleviated hydronephrosis ; the urinary output and blood pressure were normal . bun and cr returned to their previous levels and contrast - enhanced ct was performed . the scan revealed a solid mass with mild contrast enhancement that was heterogeneous ( fig . a tumor was hypothesized to have originated from the adnexa , so the patient was referred to the department of obstetrics and gynecology . a magnetic resonance imaging scan revealed hypointensity on t1-weighted images and a mixture of mildly hypointense areas with some hyperintensity on t2-weighted images . a solid tumor without a cystic component was identified ; thus , recurrence of wilms ' tumor , sex cord - stromal tumor and leiomyosarcoma were considered in the differential diagnosis ( fig . the levels of tumor markers were as follows : carbohydrate antigen ( ca ) 125 10 iu / ml , ca19 - 9 4 u / ml , carcinoembryonic antigen 0.6 mg / ml , squamous cell carcinoma antigen 1.2 ng / ml , neuron - specific enolase 31.8 ng / ml , human chorionic gonadotropin < 1.0 miu / ml and -fetoprotein 2.0 ng / ml . 2a ) ; the tumor was located in the retroperitoneal space behind the right ovary ( fig . 2b ) , and was not connected to the ovary . the tumor was in contact with the right ureter , but ureteral involvement was not observed . the greater omentum and retroperitoneal space were dissected , the right adnexa was spared and only the tumor was removed . the resected specimen was a solid mass , which appeared whitish on cross sections ( fig . lymph node invasion was observed by semicircular tumor cells with large semicircular nuclei , and a  two - cell pattern ( i.e. , large tumor cells and small mature lymphocytes ) was evident . the tumor cells stained positive for c - kit and oct3 , but negative for wilms ' tumor-1 and -inhibin ; 60% of the tumor cells stained positive for ki-67 ( fig . 5 ) . 6 ) ; thus , the dysgerminoma was hypothesized to have developed from an ectopic ovary . there was no solitary kidney , multiple complications , or residual tumor , so she received 6 cycles of etoposide as postoperative treatment and has remained recurrence - free in the 3 years since the surgery . the patient and her family provided their consent regarding the publication of the case details . an ectopic ovary is extremely rare , with an incidence of 1/93,000 ( 3 ) . supernumerary , which indicates a separate location . in 1959 , wharton et al reported 2 cases of supernumerary ovaries and 1 case of an accessory ovary ( 7 ) . since that time , < 40 cases of supernumerary ovaries alone have been reported ( 8) , with several reported cases of both supernumerary and accessory ovaries . lachman et al contended that the principal causes of these conditions were i ) ovarian tissue that was detached during pelvic surgery and implanted elsewhere , ii ) ovarian tissue that was detached due to pelvic inflammatory disease and implanted elsewhere , or iii ) abnormally located ovarian tissue due to an embryological anomaly ( 9 ) . the rationale for this distinction is as follows : of the reported cases of an ectopic ovary due to ovarian tissue that was detached during pelvic surgery or pelvic inflammatory disease and implanted elsewhere , ~50% involved salpingitis or a history of pelvic surgery or intra - abdominal surgery . the same literature described cases of an ectopic ovary due to developmental anomalies at the fetal stage . primordial germ cells migrate from the posterior wall of the yolk sac into the hindgut epithelium and then to the urogenital ridge , where they differentiate into ovarian tissue . when an anomaly occurs during this process of cell migration , ectopic ovaries may be found at varying sites , including the perimetrium , intestinal tract , mesentery , retroperitoneal space and greater omentum ( 8) . in addition , diagnosing an ectopic ovary prior to surgery is usually difficult . there are case reports where an ectopic ovary was suspected prior to surgery , when follicle stimulation with clomiphene citrate resulted in follicle development within a tumor ( 10 ) . in reported cases of an ectopic ovary where a tumor has formed , that tumor is most often a mature teratoma , followed by serous or mucinous adenoma ( 8) . in some cases of an ectopic ovary , a brenner tumor ( 4 ) , wilms ' tumor ( 5 ) , or epithelial ovarian cancer ( 6 ) have been reported . to the best of our knowledge , there are currently no case reports of a dysgerminoma developing in an ectopic ovary , as in the present case . it was previously reported that genitourinary or genetic anomalies are identified in ~1136% of the cases of an ectopic ovary ( 5,9 ) . in the aforementioned case of epithelial ovarian cancer , there are also case reports of an ectopic ovary and a unicorn uterus ( 10,11 ) . in the aforementioned case of a wilms ' tumor , the patient had both congenital renal agenesis and an ectopic ovary . the patient in our case was diagnosed with wagr syndrome and had a history of abdominal surgery for wilms ' tumor . the possibility that the surgery was responsible for separating ovarian tissue from an ovary is unlikely . the ultimate diagnosis of an ectopic ovary is based on the presence of ovarian cortex , follicles , granulosa cells , or theca cells ( i.e. , tissue specific to the ovaries ) in a resected tumor . in the present case , an initial histopathological examination led to the diagnosis of dysgerminoma , although its primary origin was not known . if a tumor is large , the possibility that that tumor contains ovarian tissue may be overlooked . in cases of an abdominal mass of unknown origin , the possibility of a tumor developing from an ectopic ovary must be taken into consideration , and a detailed histological examination must be performed . in conclusion , we herein present an extremely rare case of dysgerminoma developing in an ectopic ovary in a patient with wagr syndrome . identifying the presence of an ectopic ovary prior to surgery is difficult , but there are reports of a malignancy developing in patients with that condition . if this condition is suspected , or a retroperitoneal tumor of unknown origin is found in the abdomen , the possibility of an ectopic ovary must be kept in mind , and a detailed histological examination must be performed .
wagr syndrome is caused by an 11p13 deletion and includes wilms ' tumor , aniridia , genitourinary anomalies and mental retardation . 
 we encountered a case of a dysgerminoma originating in an ectopic ovary in a woman with wagr syndrome . 
 our patient was a 24-year - old nulliparous woman who was diagnosed with wagr syndrome . 
 the patient had undergone left nephrectomy for a wilms ' tumor and postoperative chemotherapy at the age of 7 months . 
 she also had a history of glaucoma surgery in both eyes , and was followed up at the department of pediatrics for diabetes mellitus , hypertension , liver dysfunction and hyperuricemia . 
 the patient was investigated for oliguria and had elevated levels of blood urea nitrogen ( 45 mg / dl ) and creatinine ( 5.4 mg / dl ) ; she was admitted to the hospital with acute renal failure and a computed tomography scan revealed a pelvic tumor with a long axis of 10 cm that was obstructing the right ureter . following insertion of a ureteral stent , 
 the tumor was removed . 
 the tumor had developed in the retroperitoneal space independent of the ovaries . 
 the right adnexa were normal . 
 the tumor was histopathologically diagnosed as dysgerminoma . 
 follicles were found in part of the tumor ; it was thus hypothesized that the tumor developed from an ectopic ovary . 
 the patient was administered etoposide after surgery , and has been recurrence - free for 4 years since treatment .