Vesicovaginal Fistula Visualized in Multiple Modalities

Clinical History

We present a 43-year-old female with a history of cervical cancer (stage IIIb squamous cell) who presented one-year post radiotherapy with urinary discharge and intermittent bleeding per vaginum. Subsequently she was diagnosed with a local recurrence of malignancy. Of note she had a history of Bechet’s Disease.

Imaging Findings

Contrast CT Urogram (Urographic phase): The distal portion of the right-sided nephroureteric stent can be seen in the posterior aspect of the bladder. Part of the stent extends from the bladder to the vault of the vagina. Contrast is seen within the bladder and within the vagina due to the communicating fistula. There is air in the bladder anteriorly (fig 1).

Pelvic MRI (PV gel contrast) T2 weighted sagittal image: Gel can be visualized extending from the vaginal vault to the posterior aspect of a decompressed bladder indicating the presence of a large VVF (fig 2).

PET: Fluorodeoxyglucose (FDG) avidity can be seen in the bladder and delineating the vaginal vault (fig 3). An axial fused PET/CT image again shows FDG accumulation in the vagina (fig 4).

Anterograde Ureteric Stent Placement: The distal part of the guide wire can be seen passing into the vagina. (fig 5).

Discussion

This patient has a number of risk factors that predispose to urogenital fistula formation; exposure to pelvic radiotherapy, urogenital malignancy and vasculitic disease [1–3]. Radiotherapy and vasculitis damage the small vessels supplying the pelvic mucosal surfaces. Subsequent intimal proliferation can lead to a pathological narrowing and occlusion of these blood vessels. This process is known as endarteritis obliterans and can cause mucosal necrosis and fistula formation [4].

In patients with gynaecological malignancy VVF and enterovaginal fistulas are most commonly encountered [4]. VVF is associated with significant morbidity. Incontinance, pain and bleeding are known complications [4, 5]. However, fistula formation is relatively rare in women with cervical cancer. One study retrospectively reviewed 2096 women that were treated for cervical cancer over a ten-year period. It found that 1.8% of the cohort developed a urogenital fistula [6].

In patients who develop a fistula during treatment for a gynaecologic malignancy it is crucial to determine whether or not the fistula is secondary to tumour recurrence or due to treatment effects (i.e. surgery or radiotherapy). Imaging plays a key role in this differentiation and is a crucial aspect in determining the correct therapeutic avenue to take in order to optimize patient outcomes [4].
VVF can be diagnosed by direct examination where urine is visualized leaking in to the vagina; intra-vesicular dye may be used to aid in this process [5]. A number of radiological investigations can be performed in order to delineate the location, complexity and precise course of the fistula. Often a number of modalities must be used to achieve an accurate diagnosis and to assist in management decisions i.e. pre-surgical planning [4].

MRI is the modality of choice for staging and monitoring local gynaecological malignancies [4, 7]. It provides detailed soft tissue images and can aid in the detection of a number of complications i.e. fistula formation, fibrosis post radiotherapy and tumor recurrence [4]. The use of gadolinium enhanced MRI increases sensitivity with regards to fistula detection [1]. One study involving 15 patients found that MRI correctly identified 91% of vaginal fistulas prior to clinical diagnosis [8].

VVF is a complex clinical entity requiring multi-modal team care. Cross sectional imaging and IR plays a central role in patient management.

Differential Diagnosis List

Final Diagnosis

Vesicovaginal Fistula

URL:	https://www.eurorad.org/case/12891
DOI:	10.1594/EURORAD/CASE.12891
ISSN:	1563-4086