Vesical endosalpingiosis: a case of probable metaplastic origin

Endosalpingiosis of the urinary bladder is a rare and morphologically complex tumour-like lesion.  There are two theories to describe its pathogenesis; implantation and metaplasia. Here we present an incidental case of pure endosalpingiosis in a 50-year-old woman that supports a metaplastic mode of development, and review the recommended management for this unusual diagnosis.

Endosalpingiosis is the presence of ectopic, non-descript glandular tissue lined with tubular epithelium.  It is a tumour-like lesion of mullerian origin that, together with endometriosis and endocervicosis, are collectively referred to as mullerianoses [1-2].  It is not uncommon for endosalpingiosis to co-exist with endometriosis; their clinical presentation, course and response may be very similar [3].  The presence of pure endosalpingiosis within the urinary bladder is rare and, to date, only four cases have been reported [4-7].  This is in contrast to that of the pelvis, which is more common, although usually diagnosed incidentally as part of the diagnostic work-up for pelvic pain [3,8]. This report describes a case of pure vesical endosalpingiosis in a perimenopausal woman.  It is one of only a small number of cases demonstrating a metaplastic origin.

A 50-year-old Afro-Caribbean woman presented initially to the gynaecology department with a three-week history of pelvic pain associated with per vaginal bleeding and dysuria.  Her medical history was marked by a long period of endometriosis and amenorrhoea recently followed by new onset menorrhagia. A Mirena intra-uterine device (IUD) had been in situ for the past 8 years.  There was no history of urogenital infection, trauma or lithiasis, nor did she have any significant previous surgical history.

Physical examination revealed suprapubic tenderness with a normal bimanual palpation.  No strings of the IUD could be seen on direct visualisation of the cervix – see comment below.  An urgent pelvic ultrasound scan demonstrated a well positioned IUD and a 3.2 x 2.6 x 3.8cm heterogenous, irregular mass arising from the bladder wall that appeared to contain both solid and cystic areas (Fig. 1).

A subsequent rigid cystoscopy under general anaesthetic revealed a diffuse mass with cystic lesions on the posterior wall of the bladder. The features were not typical of a transitional cell carcinoma.  Six deep biopsies were taken of the cystic areas.

Histologically, the mass included mildly inflamed, oedematous mucosa.  Two deep biopsies included smooth muscle bundles containing cystic spaces, one of which was lined by columnar, focally-ciliated epithelium (Fig. 2 and 3).

Conventional H&E and immunohistochemical staining for CD10 failed to demonstrate endometrial-type stroma, and no mucin to suggest endocervical differentiation was seen.  The features were reported as characteristic of endosalpingiosis by our histopathologists.

Mullerianosis of the urinary bladder is a rare occurrence and although a number of cases have been reported [4-7], very few of these describe lesions that are composed entirely of endosalpingiosis, as was seen in the aforementioned case.

There are two theories to explain the pathogenesis of endosalpingiosis.  The first is an implantative origin, as first described by Young and Clement1.  This theory proposes the seeding of ectopic tubal tissue as a result of pelvic surgery, such as a previous caesarean section.  The second theory, first suggested by Donné et al. [2] argues a role for metaplasia in those cases with no previous pelvic surgery and where multiple Mullerian tissues co-exist.  This theory is also favoured by the association of the overlying vesical peritoneum with the location of mullerian lesions in the posterior wall or bladder dome. Further evidence supporting this possibility is provided by a case of endosalpingiosis in continuity with glandular cystitis.[9]

The case in question supports a metaplastic origin of endosalpingiosis.   Although no evidence of other Mullerian tissue was seen within the bladder lesion, the patient had a confirmed diagnosis of long-standing endometriosis.  Furthermore, there was no previous history of pelvic surgery or bladder instrumentation to suggest implantation.

Endosalpingiosis often presents asymptomatically in contrast to the other Mullerian lesions of endocervicosis and endometriosis [1]. It is this paucity of symptoms that may account for its apparently rare incidence, and the condition is potentially grossly under-represented if symptoms are incorrectly attributed to other uro-gynaecological conditions with similar clinical presentations.  Investigations tend to be directed by the clinical presentation.  In this case, pelvic pain and per vaginal bleeding with dysuria prompted a full gynaecological and urological work-up with a subsequent histological diagnosis.

The specific management of endosalpingiosis is not fully established; however described therapies have included transurethral resection with follow-up cystoscopy at 4 and 9 months post-operatively [1, 5].  Comparisons can be made with the treatment of bladder endometriosis, another of the Mullerianoses.  Two types of treatment are employed: medical (hormonal), and surgical therapies [10].  Hormonal treatment provides a good initial response, is well tolerated by patients, and can be discontinued if adverse effects occur.  LH-RH analogues are the most commonly used treatments nowadays, whilst oestrogens, progesterones and androgens have fallen into disuse due to their many side effects [10]. Conservative measures alone however do not lead to a definitive cure, but merely suppress the disease temporarily.  In order to prevent further recurrence and achieve the best prognosis, a combination of medical therapy with surgery is advised [10].  The most commonly employed technique of recent years is transurethral resection or biopsy of the lesion to confirm the diagnosis, followed by hormonal therapy.  Further surgery including partial cystectomy may be warranted, especially if the lesion is transmural [11].  Aggressive measures such as this however, should not be taken in perimenopausal women, as the lesions usually regress after the menopause [10].

Like endometriosis, endosalpingiosis tends to recur and primary ureteric disease has been described [12], although it is unknown whether bladder disease can recur within the upper urinary tract, or whether this is in fact a primary disease.  If the diagnosis is in doubt and imaging suggests malignancy then partial cystectomy is recommended [4].  It has been suggested that, given the relative asymptomatic nature of the condition, long-term surveillance is advisable [6].  A recommended approach is regular cystoscopy at three-monthly intervals initially for two years, twice-yearly for a further two years, and then annually thereafter [6]. However, these recommendations have been made on the basis of minimal evidence, therefore follow-up should be instigated on a case-by-case basis.  Given the potential for upper tract disease, renal ultrasound or contrast computed tomography should be considered.

In our case, the patient was discharged and referred back to the gynaecology department following a multidisciplinary team discussion.  Her symptoms resolved despite only a conservative approach and without further resection of the lesion. At the time of writing, she is under regular review within the gynaecology outpatient department.

Vesical endosalpingiosis, although uncommon, may present a diagnostic conundrum both to the gynaecologist and the urologist.  If the condition is as under-represented as the evidence suggests, an increased awareness of the range of clinical presentations is required.  Subsequently, an increased yield of histological diagnoses in those patients in which the diagnosis is suspected will advance our understanding of the condition and its appropriate management.

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