Introduction

Hunner's ulcer is a distinctive inflammatory lesion presenting a characteristic deep rupture through the mucosa and submucosa provoked by bladder distension. Despite the name, it is not an ulcer. ESSIC, therefore, has decided to use the name Hunner’s lesion instead of Hunner's ulcer. The detection of Hunner's lesions is in general only possible at cystoscopy with hydrodistension under proper anesthesia by an experienced urologist with training to detect them.

Definition

The following definition by Magnus Fall was accepted by ESSIC:

The Hunner’s lesion typically presents as a circumscript, reddened mucosal area with small vessels radiating towards a central scar, with a fibrin deposit or coagulum attached to this area. This site ruptures with increasing bladder distension, with petechial oozing of blood from the lesion and the mucosal margins in a waterfall manner. A rather typical, slightly bullous edema develops post-distension with varying peripheral extension.

Types

Interstitial cystitis (IC) with Hunner's lesions is called classic IC as opposed to nonulcer IC when Hunner's lesions are not found. Classic IC is the same as BPS type 3A, 3B or 3C depending on whether biopsies were done and, if so, the biopsy findings. It is not clear to date whether the nonulcer and classic types represent different stages of a single disease, or whether they are different disease entities.
Patients with Hunner's lesions are 10 years older on average than those without but this difference is compatible with both theories. There is no relationship between symptoms including pain scores and the presence of Hunner's lesions. The bladder capacity under general anaesthesia has been found to be significantly smaller in patients with Hunner's lesions.

Luminal nitric oxide (NO) measurement in the bladder of BPS patients has shown that patients with Hunner's lesions have high NO levels irrespective of symptoms, while those without Hunner's lesions have normal levels. Bacterial infection of the bladder must be excluded as this also causes high NO levels in the bladder. The measurement is a simple procedure and done using an intravesical catheter with a silicon balloon. It requires a NO measuring device that is not generally available in hospitals; it costs about € 25,000.

The lack of data that BPS patients without Hunner's lesions progress to BPS with Hunner's lesions is in line with the hypothesis that they represent different diseases. Future studies, in which patients are classified according to the BPS types as proposed by ESSIC, are needed to clarify this issue.

Prevalence

In urologic centers with expert skills to detect Hunner's lesions, Hunner's lesions are detected in about 50% of the patients with BPS. The majority of BPS patients with Hunner's lesions, however, are probably not recognized in centers with less experience. This underdiagnosis is probably due to a combination of factors such as:

1. the confusion caused by the name Hunner's ulcer while it is not an ulcer: the term Hunner's ulcer suggests that it can be seen at cystoscopy without hydrodistension
2. the detection of Hunner's lesions is almost impossible if cystoscopy is performed without hydrodistension
3. many urologists suppose that Hunner's lesions are rare; the fact that they rarely detect them is considered to be in line with this false impression
4. even when cystoscopy with hydrodistension is performed, Hunner's lesions are likely to be detected only by experienced urologists; biopsy may be necessary to prove that it is a Hunner's lesion and/or to exclude a carcinoma in situ

Treatment

Bladder pain may improve dramatically when the Hunner's lesions are treated by electrocoagulation, laser or resection. Unfortunately, Hunner's lesions tend to recur but the interval may vary between several months and e.g. more than 5 years.

See also: Diagnostic Criteria, Classification, and Nomenclature for Painful Bladder Syndrome/Interstitial Cystitis: An ESSIC Proposal.
Eur Urol 2008;53:60-7

Joop P van de Merwe