Clinical History
A 75-year-old female with unremarkable medical history (menopause at 49 years of age), suffering from dysuria and pelvic fullness since three months presented to our hospital. She was sent to the radiology department by a gynaecologist to investigate the suspected presence of a large periurethral mass lesion.
A physical examination showed senile involution of genitalia. Negative Papanicolaou test.
Imaging Findings
Pelvic MRI (Figs.1&2) confirmed the previous sonographic finding (not shown) of a well-demarcated, septated cystic-like periurethral mass which almost completely encircled the urethra with a characteristic "saddlebag" axial configuration, measuring 5.5-cm longitudinal and 4-cm maximum transverse diameters; it extended along the entire urethra and minimally displaced it towards the left side, and the bladder base upwards; it showed fluid-like signal intensity on all sequences, non-restricted diffusion, and mild, thin uniform peripheral enhancement, without surrounding fat inflammatory changes.
The presence of a thin, short dorsal neck connecting the periurethral cystic-like mass with the urethral lumen was confirmed at transvaginal ultrasound (Fig.3). On these basis, the imaging findings were interpreted as consistent with a large, typical saddlebag-shaped urethral diverticulum. The patient was offered surgical incision but ultimately declined.
Discussion
Female urethral disorders cause unspecific complaints such as dysuria, dyspareunia, urinary frequency, urgency or incontinence, recurrent infections. Clinical assessment is often inconclusive, thereby imaging is generally helpful to assess the presence, extent and nature of abnormalities, particularly before surgical treatment. In the past, double-balloon urethrography and voiding cystourethrography were used to depict the urethral lumen, but lacked cross-sectional information on adjacent structures. Nowadays MRI shows the female urethra and surrounding tissues with high-resolution multiplanar images and superb soft-tissue contrast, even without endoluminal coils, and is therefore the best technique for suspected urethral or periurethral pathologies with or without palpable swelling or mass [1-5].
Female urethral disorders are broadly categorized as solid or cystic. Acquired urethral diverticulum (AUD) by far represents the commonest form encountered in clinical practice in adult women. AUD are found in 4-6% of the general population and in up to 40% of women with irritative voiding symptoms or recurrent urinary infections. The characteristic complaints include postvoiding dribbling, dysuria, dyspareunia, a tender periurethral mass yielding fluid or pus. AUD lack an epithelial lining, and probably result from inflammation and obstruction of the periurethral glands, which ultimately rupture into the urethral lumen. Delayed diagnosis after years with symptoms is common [1, 2, 4].
MRI optimally visualizes AUDs, which appear as fluid-containing T2-hyperintense; signal intensity may sometimes be atypical due to proteinaceous or haemorrhagic content. AUD generally arise at the postero-lateral aspect of the mid-urethra, and their configuration ranges from round or oval unilocular lesions, to C- or horseshoe-shaped diverticula extending partially around the urethra, to circumferential cystic-like cavities. The key information to be provided to the surgeon include: a) diverticular location and degree of extension around the urethral circumference; b) presence, position and width of the connecting “neck” between the AUD to the lumen; the latter is appreciable on axial images in approximately half of cases. Complications include superinfection, calculi (5% of cases) and exceptionally tumour development, and are suggested by filling defects, irregular or enhancing borders [1-5].
The differential diagnosis include the small-sized caruncle at the distal meatus, periurethral cysts (typically teardrop-shaped located at the distal urethra in close proximity to the vagina), vaginal cysts without communication with the urethra (on the antero-lateral vaginal wall) and Bartholin cysts (at the postero-lateral aspect of the distal vagina, below the symphysis pubis) [1, 3, 4].
Transvaginal or endoscopic diverticulectomy is the treatment of choice for AUD, including complete resection of the neck to prevent recurrence [2].
Differential Diagnosis List
Saddlebag-shaped diverticulum of the female urethra
Periurethral (Skene duct) gland cysts
Vaginal (Mullerian
Gartner duct) cysts
Bartholin gland cyst
Urethral caruncle
Ectopic ureter / ureterocele
Final Diagnosis
Saddlebag-shaped diverticulum of the female urethra
