An 11-year-old Chinese girl presented with 3 months of intermittent cramp-like lower abdominal pain occurring every few days and lasting several minutes. She had no fever, vomiting, or dysuria. Since infancy, she had experienced continuous urinary dribbling between normal voiding episodes, occasionally accompanied by nocturnal enuresis. Multiple courses of acupuncture had been attempted without improvement. She had no history of urinary tract infection, hematuria, or trauma. Growth and neurodevelopment were normal. There was no family history of ovarian tumors, basal cell carcinomas, medulloblastoma, or other features suggestive of Gorlin syndrome. Perinatal history was unremarkable.

Physical examination revealed a well-appearing afebrile child with mild lower abdominal tenderness and no palpable mass. Abdominal examination showed no distension, shifting dullness, or fluid wave suggestive of ascites. External genitalia were normal with Tanner stage I development, and there were no signs of virilization (hirsutism, clitoromegaly, or acne). A tiny orifice near the posterior urethra suggested an ectopic ureteral opening.

Laboratory evaluation included serum tumor markers and hormonal assessment. Serum CA125 was 18.2 U/mL (normal <35 U/ml), AFP was 2.1 ng/ml (normal <10 ng/ml), and β-hCG was <0.1 mIU/ml (normal <5 mIU/ml). Sex hormone panel revealed prepubertal levels: estradiol 12 pg/ml, testosterone 8 ng/dl (normal prepubertal <20 ng/dl), FSH 3.2 mIU/ml, and LH 1.8 mIU/ml. These findings excluded hormone-secreting tumors such as fibrothecoma or other sex cord-stromal tumors with endocrine activity.

Pelvic MRI and MR urography revealed bilateral solid ovarian masses and a left duplex collecting system with complete ureteral duplication. The anatomical configuration consisted of two separate renal moieties within a single renal fossa, each with its own ureter: the lower-pole ureter inserted orthotopically into the bladder trigone, while the upper-pole ureter was markedly dilated (approximately 16 mm diameter), coursing caudally and inserting ectopically into the posterior urethra. The upper moiety showed hydronephrosis with cortical thinning; the lower moiety appeared preserved. No peritoneal implants or free fluid were identified (Figures 1A,B). Voiding cystourethrography showed no vesicoureteral reflux. Renal scintigraphy (DMSA) confirmed minimal function (8%) in the left upper moiety, supporting the decision for ureteral reconstruction rather than upper-pole nephrectomy.

On May 9, 2023, diagnostic cystoscopy followed by laparoscopic bilateral ovarian tumor resection was performed. Cystoscopy demonstrated normal orthotopic ureteral orifices and a pinpoint ectopic orifice on the posterior urethral wall with intermittent urine efflux, confirming the suspected ectopic ureteral opening. Laparoscopy confirmed bilateral enlarged ovaries with firm, nodular surfaces. Inspection of the peritoneal cavity revealed no ascites, peritoneal deposits, or omental involvement. The left duplex ureter was immediately apparent, with the upper branch markedly dilated. Both tumors were completely excised while preserving maximal normal ovarian tissue (Figures 2A–C).

Intraoperative frozen section suggested spindle-cell stromal tumor consistent with ovarian fibroma. Final histopathology confirmed bilateral ovarian fibromas with focal calcification, composed of interlacing bundles of bland spindle cells within collagen-rich stroma. Immunohistochemistry showed diffuse vimentin positivity, focal SMA and inhibin-α positivity, cytoplasmic β-catenin staining, and Ki-67 index 3%–5%, supporting benign sex cord–stromal tumor without thecal or luteinized components (Figures 3A–C).

Three months later (August 30, 2023), the patient underwent staged urologic reconstruction via laparoscopy. The surgical procedure consisted of: (1) mobilization and identification of the dilated ectopic upper-pole ureter; (2) excision of the distal ectopic ureteral segment including its insertion into the posterior urethra; (3) spatulation of the transected upper-pole ureter; (4) end-to-side ureteroureterostomy anastomosing the upper-pole ureter to the ipsilateral normally-draining lower-pole ureter using interrupted 5-0 absorbable sutures; and (5) antegrade placement of a 4.7 Fr double-J ureteral stent across the anastomosis. This approach preserved the functioning lower moiety while redirecting upper-pole drainage through the normal ureteral pathway, eliminating the ectopic insertion responsible for urinary incontinence. The postoperative course was uneventful.

Urine dribbling resolved completely following ureteroureterostomy. Follow-up ultrasonography five months later (January 2024) showed stable mild hydronephrosis without progression. At 12-month follow-up (May 2024), the patient had spontaneous menarche, indicating preserved ovarian function. No tumor recurrence was observed. The clinical course is summarized in Table 1.

Trio whole-exome sequencing using peripheral blood samples identified two heterozygous variants of uncertain significance (VUS) in genes involved in embryonic development and extracellular-matrix regulation (Table 2).

The SUFU missense variant c.544G>A (p.Asp182Asn), inherited from the phenotypically normal father, alters a highly conserved residue within the suppressor domain. This variant is absent from gnomAD (allele frequency <0.0001) and is predicted disease-causing by MutationTaster (REVEL score 0.82). Structural modeling predicted local conformational disturbance that may compromise SUFU's regulatory function in the Sonic Hedgehog pathway (Supplementary Figure S1) (8, 9).

The second variant, c.1946A>T (p.Asn649Ile) in FN1, was inherited from the phenotypically normal mother. This variant affects a residue in the fibronectin type III domain, is rare in gnomAD (allele frequency 0.00004), and is predicted pathogenic by PolyPhen-2 (score 0.958) and SIFT (deleterious). Neither parent nor the patient's four-year-old sister showed clinical features. Given that both variants regulate mesodermal differentiation, multilocus genomic variation may underlie this combined ovarian–renal phenotype (10).

Strengths of this case include comprehensive multimodal evaluation integrating advanced imaging, detailed histopathology, and trio whole-exome sequencing, along with excellent clinical outcomes with documented functional recovery. Limitations include the VUS classification of both variants without functional validation, the single-case design precluding causal inference, and limited long-term follow-up for tumor recurrence risk assessment.