A giant serous papillary cystadenofibroma mimicking a bladder tumor: A diagnostic pitfall.

A 54-year-old female patient presented to the urology outpatient clinic with a 4-year history of urge urinary incontinence. Her past medical history was significant for chronic obstructive pulmonary disease, hypertension, diabetes mellitus, and a 100 pack-year smoking history. Initial laboratory evaluation, including urinalysis, was unremarkable. Post-void residual urine measurements were elevated at 570 mL and 370 mL on repeat assessment. A urinary catheter was inserted; however, only 50–100 mL of urine was drained, which was inconsistent with the measured residual volume. This discrepancy prompted urgent imaging evaluation. Ultrasonography revealed a 50 × 30 mm irregular iso-hyperechoic lesion located at the posterior aspect of the bladder lumen, without detectable vascularity on Doppler imaging, suggesting a possible bladder tumor ( Fig. 1 ). Fig. 1 Ultrasonographic image demonstrating an iso-hyperechoic lesion located at the posterior aspect of the bladder lumen, initially suspicious for a bladder tumor. Ultrasonographic image demonstrating an iso-hyperechoic lesion located at the posterior aspect of the bladder lumen, initially suspicious for a bladder tumor. Given the patient's significant smoking history and the suspicious ultrasonographic findings, cystoscopy was indicated and performed within one week. Cystoscopic evaluation demonstrated normal bladder mucosa without any evidence of an intravesical lesion. This marked discordance between ultrasonographic findings and endoscopic assessment raised strong suspicion for an extravesical pathology rather than a primary bladder tumor. The patient was therefore referred to the gynecology department. Subsequent cross-sectional imaging, including contrast-enhanced computed tomography and magnetic resonance imaging, was undertaken to better characterize the lesion, determine its origin, and assess its relationship with adjacent pelvic structures. CT urography demonstrated a large pelvic mass measuring approximately 130 × 120 mm with cystic degeneration areas, exerting extrinsic compression on the bladder without direct invasion ( Fig. 2 ). MRI further characterized the lesion as a 141 × 100 × 124 mm cystic mass adjacent to the uterus, hypointense on T1-weighted images and hyperintense on T2-weighted images, with thickened walls ( Fig. 3 ). Fig. 2 Contrast-enhanced CT urography images. (A) Coronal image demonstrating a contrast-filled urinary bladder with an adjacent large pelvic mass exerting extrinsic compression. (B) Sagittal image demonstrating the pelvic mass without evidence of intravesical invasion. (C) Axial image demonstrating the cystic nature of the lesion and its internal solid component closely mimicking an intravesical bladder tumor. Fig. 3 Magnetic resonance imaging findings. (A) Sagittal T1-weighted image demonstrating a large cystic adnexal mass adjacent to the bladder without evidence of an intravesical lesion. (B) Axial T2-weighted image demonstrating the cystic lesion with internal solid components creating an appearance highly suggestive of a bladder neoplasm. (C) Sagittal T2-weighted image demonstrating extrinsic compression of the bladder without evidence of intravesical invasion. Contrast-enhanced CT urography images. (A) Coronal image demonstrating a contrast-filled urinary bladder with an adjacent large pelvic mass exerting extrinsic compression. (B) Sagittal image demonstrating the pelvic mass without evidence of intravesical invasion. (C) Axial image demonstrating the cystic nature of the lesion and its internal solid component closely mimicking an intravesical bladder tumor. Magnetic resonance imaging findings. (A) Sagittal T1-weighted image demonstrating a large cystic adnexal mass adjacent to the bladder without evidence of an intravesical lesion. (B) Axial T2-weighted image demonstrating the cystic lesion with internal solid components creating an appearance highly suggestive of a bladder neoplasm. (C) Sagittal T2-weighted image demonstrating extrinsic compression of the bladder without evidence of intravesical invasion. The patient was managed by the gynecology department and underwent total hysterectomy with left salpingo-oophorectomy and omentectomy. Histopathological examination revealed a serous papillary cystadenofibroma. Additional findings included chronic cervicitis, cystic endometrial atrophy, leiomyoma with adenomyosis, and mature adipose tissue in the omentum.

Ömer Eyüp: Conceptualization, Data curation, Investigation, Visualization, Writing – original draft, Writing – review & editing. Fatih Koçoğlu: Conceptualization, Writing – review & editing, Supervision, Validation. Ayşenur Balıkçı: Data curation, Investigation. Mustafa Serkan Koncuk: Resources, Validation.

Among gynecological lesions, bladder endometriosis is the most commonly reported condition mimicking bladder neoplasms in imaging studies, often presenting with hematuria and mass-like lesions involving the bladder wall ^ 1 , 2 , 3 Deep infiltrating endometriosis may also involve the urinary bladder and simulate malignant bladder lesions ^ 8 Ovarian cystadenofibromas are rare benign epithelial tumors that may demonstrate complex cystic and solid components, frequently leading to misinterpretation as malignant pelvic masses on imaging ^ 4 , 5 , 6 In most reported cases, these tumors are incidentally discovered during surgery performed for other gynecological conditions ^ 5 . Ultrasonography remains the first-line imaging modality in the evaluation of bladder lesions and demonstrates high diagnostic accuracy for detecting bladder tumors; however, extravesical pelvic masses may occasionally mimic intravesical pathology, leading to diagnostic uncertainty ^ 7 . Cross-sectional imaging techniques such as CT and MRI play a crucial role in defining lesion origin and distinguishing extravesical compression from true bladder invasion ^ 6 . In the present case, the lesion resulted in a false intravesical tumor impression on ultrasonography despite the absence of true bladder involvement on cystoscopic and radiologic evaluation, underscoring the importance of multimodal imaging correlation in atypical presentations.

Pelvic masses may mimic bladder tumors on ultrasonography, potentially leading to diagnostic confusion. A normal cystoscopic evaluation should prompt consideration of extravesical pathology. Multimodal imaging plays a crucial role in establishing an accurate diagnosis. Serous papillary cystadenofibroma presenting as a suspected bladder tumor is exceedingly rare and represents an important diagnostic pitfall.

Pelvic masses may occasionally create diagnostic confusion because of the close anatomical relationship between gynecologic and urologic organs. Bladder endometriosis is the most commonly reported gynecological condition mimicking bladder neoplasms in imaging studies ^ 1 , 2 , 3 Ovarian serous cystadenofibromas are rare benign epithelial tumors characterized by complex cystic and fibrous morphology and variable imaging features that may simulate malignant pelvic lesions on radiologic and ultrasonographic evaluation ^ 4–6 Although adnexal masses are frequently associated with diagnostic uncertainty, presentation as a lesion clinically and radiologically suspicious for an intravesical bladder tumor is exceedingly rare. We report a rare case of serous papillary cystadenofibroma initially interpreted as a bladder tumor on ultrasonographic examination, highlighting an important diagnostic pitfall.