Mullerianosis of the urinary bladder.

Mullerianosis of the urinary bladder is a rare and morphologically complex tumor-like lesion, composed of several types of mullerian lesions like endometriosis, endocervicosis, and endosalpingiosis. This disease occurs in women of reproductive age group. Implantative and metaplastic origins have been suggested in the pathogenesis.

INTRODUCTION

Mullerianosis of the urinary bladder is a very rare and complex tumor like lesion. It is composed of several mullerian type lesions like endometriosis, endocervicosis and endosalpingiosis occurring together. Mullerianosis of the urinary bladder was first described by Clement and Young in 1996.[1] This rare lesion is usually seen in women of child bearing age.

CASE REPORT

A 32 year old lady presented with complaints of dysuria and burning micturition during menstrual cycles. Abdominal examination and per speculum examination was normal. Urine microscopy revealed 12-15 RBCs and 1-2 WBCs /HPF. Cystoscopy showed a 4 cm raised papilliferous area in the right lateral wall of bladder with intact overlying mucosa. A clinical diagnosis of bladder cancer was made. Transurethral resection of the lesion was performed. There was no chocolate coloured material identified during resection. Histopathological examination of the biopsy specimen revealed endometrial glands and stroma along with endocervical type of glands and glands lined by ciliated cells in the bladder wall [Figures 1 and 2]. These findings indicate that the bladder lesion was mullerian in nature with endometriosis, endocervicosis and endosalpingiosis. Postoperatively the patient was treated with 5 doses of parentral GnRH analogue. The patient was found to be asymptomatic on follow up of 2 years but on cystoscopy a mass lesion was persistent which was smaller in size (1.5 cm) in comparison to the earlier lesion.

Figure 1

(a) Endometrial type of glands and stroma extending deep within the bladder wall (b) glands lined by tubal type epithelium (Hematoxylin & Eosin (H&E); ×200)

Figure 2

Endocervical glands in the bladder wall lined by mucinous tall columnar epithelium with basal nuclei along with an endometrial gland (arrow) H & E; ×200. Inset shows mucicarmine positivity of endocervical type glands ×200

DISCUSSION

Urinary bladder is the most common site of genitourinary endometriosis. In addition to classical endometriosis, glandular lesions made up of endocervical type glands (Endocervicosis) can also occur in the bladder. Endocervicosis of the urinary bladder was first described by Clement and Young in 1992.[2] This lesion is usually seen in women of child bearing age and presents as a mass in the posterior wall or dome of the bladder with suprapubic pain. Other mullerian tissues such as tubal epithelium have been reported in the bladder under the name of endosalpingiosis.[3] The term mullerianosis is used when there is a complex combination of these mullerian-type lesions.[1] To our knowledge, only five cases of mullerianosis of urinary bladder have been reported.[4]

Endometriosis of the urinary bladder classically affects women in the second to fifth decade of life but may be seen in postmenopausal women receiving exogenous oestrogens. Endometriosis may also be rarely seen in men with prostatic carcinoma who have received exogenous oestrogen therapy. Endometriosis usually presents as a mass lesion on cystoscopy, most commonly in the trigone or posterior wall. About one third of these cases resemble a neoplasm as seen in this case. Microscopy is similar to endometriosis elsewhere.

Endocervicosis is characterised by extensive involvement of bladder wall by benign / mildly atypical columnar mucin secreting endocervical glands. Mullerianosis is associated with presence of tubal-type epithelium in addition to endometriosis and endocervicosis.

The pathogenesis of these lesions remain debatable and both implantative and metaplastic origins have been suggested.[4] Implantative origin is supported by a frequent past history of pelvic surgery in endometriosis and endocervicosis. In the present case there was no history of surgery hence possibility of metaplastic origin is suggested.

The differential diagnosis of mullerianosis would include a variety of lesions both neoplastic and non-neoplastic. Possibility of a minimal deviation adenocarcinoma of cervix infiltrating the bladder has to be ruled out. In the present case, cervix was normal on examination and the clinical course was indolent. Minimal deviation adenocarcinoma will show at least focal atypia, which was lacking in the present case. Benign lesions like cystitis cystica and cystitis glandularis can mimic mullerianosis but both these entities do not show deeply situated glands as in mullerianosis.[5] Urachal remnants in the bladder can also show tubular structures lined by mucinous epithelium however they are usually incidental findings observed near the dome of bladder and is usually surrounded by a loose peritubular fibromuscular tissue.[5]

CONCLUSION

Mullerianosis of the bladder is a rare lesion, which may present as a mass lesion mimicking a tumor. Awareness of this lesion is essential to facilitate its distinction from adenocarcinoma.