Müllerianosis: A Case Report

Background: Müllerianosis is a rare condition with ∼40 reported cases to date. It presents clinically as hematuria, dysuria, and pelvic pain. It most commonly affects the urinary bladder and affects women of fertile age. Case Presentation: This is a case of a 43-year-old Chinese woman, with a medical history of thyroid cancer post-thyroidectomy. She had no history of gynecologic nor pelvic procedures done.

Even though müllerianosis has a benign course, it is important to note that it may also have an atypical presentation such as acute renal colic. Also, malignancy will need to be ruled out as some cases have been associated with malignancy. In this case, the initial CT scan showed adjacent urinary bladder wall thickening near the uterus. This prompted further imaging with MRI to exclude uterine involvement. Fortunately, histology confirmed it to be müllerianosis.

bladder cancer, education, imaging

and Background Müllerianosis of the urinary bladder is a rare condition with ∼40 reported cases to date. It was first described by Young in 1996 as a condition whereby two of three Müllerian-derived tissues are identified within the bladder epithelium. It usually presents clinically as hematuria, dysuria, and pelvic pain, which may or may not be associated with menstruation. It most commonly affects the urinary bladder and affects women of fertile age. Radiologically and macroscopically, it typically presents as a polypoid mass in the dome or posterior wall of the bladder. Histologically, it consists of glands of varying size lined by endometrial, endocervical, or tubal epithelium. It is considered a benign pathology, however, it may present atypically like acute renal colic1 and more importantly malignancy still needs to be ruled out.1 Presentation of Case This is a case of a 43-year-old Chinese woman, with a medical history of thyroid cancer post-thyroidectomy. She had no history of gynecologic nor pelvic procedures done. She was referred to the urology clinic from the local general practitioner for an incidental bladder mass measuring 1.2 cm on ultrasonography. The patient had no urinary symptoms, there was no history of gross hematuria, nor dysuria. Urinalysis and urine cultures showed findings of urinary tract infection (UTI) for which the patient was treated with antibiotics. The patient underwent further work-up. CT urogram (Fig. 1) was done and showed an endophytic nodular soft tissue lesion measuring 1.8 × 1.2 cm arising from the posterior wall of the urinary bladder with mild contrast enhancement associated with adjacent urinary bladder wall thickening near the uterus. There was no overt extravesical extension. MRI was done to evaluate the lesion more clearly. MRI findings (Fig. 2) showed the same lesion and another tiny lesion more superiorly. There was a clear fat plane seen between the bladder and the uterus. There was no extravesical extension nor involvement of the uterus. The patient had a flexible cystoscopy (Fig. 3), and a posterior wall bladder nodule that appeared cystic (bluish) was seen and a nodularity was noted below the lesion at the posterior wall. It appeared to be extending from outside into the bladder, the mucosa was smooth over the lesion. The patient then underwent a transurethral resection of the bladder lesion. Intraoperatively there were three lesions measuring 13, 10, and 5 mm all located at the posterior wall. These were all resected during the procedure. Histology (Fig. 4) of the lesions showed a polypoid bladder tissue with underlying cyst lined by bland cells with occasional cilia. No endometrial type stroma is seen deep to the cyst lining cells. No malignancy was seen. Findings were suggestive of müllerianosis.

and Literature Review Müllerianosis is still considered a rare condition with ∼40 reported cases to date. It usually presents clinically as hematuria, dysuria, and pelvic pain that may or may not be associated with menstruation. It most commonly affects the urinary bladder and affects women of fertile age. Radiologically and macroscopically, it typically presents as a polypoid mass in the dome or posterior wall of the bladder.2 In women, müllerianosis can be the cause of an asymptomatic bladder mass. But reports have shown these cases can cause lower urinary tract symptoms.2 In this case, the patient did not present with the usual symptoms. She was referred for a bladder lesion seen on ultrasonography. The urinalysis showed a UTI picture that may or may not be caused by the lesion. A CT urogram showed a bladder lesion that was associated with adjacent urinary bladder wall thickening near the uterus. This prompted further imaging with MRI to exclude uterine involvement. Fortunately, MRI findings did not show uterine involvement. Histopathologic hallmark of müllerianosis is the presence of a mixture of at least two of three müllerian-derived components. Müllerian lesions derive from the müllerian accessory system and may present as endometriosis, endosalpingiosis, or endocervicosis, with the first being the most common presentation and endocervicosis alone the most exceptional. There are few theories behind müllerianosis. The implantation theory, by Young and Clement, proposes that müllerian tissue implants in the urinary bladder wall during cesarean section or pelvic surgery. This is supported by the fact that patients of müllerianosis have a frequent clinical history of cesarean section or pelvic surgery. However, approximately half of the cases including our case did not have any history of these procedures. Donne et al. proposed the metaplastic theory because the presence of multiple müllerian components may reflect the lesion's capacity of differentiation, and the location of müllerianosis is exclusively restricted to the posterior wall of the urinary bladder, an area that topographically corresponds to its peritoneal covering and that may be particularly receptive to female hormones.3 In this case, the patient had no history of any pelvic surgery or cesarean section, which would prefer the latter theory. Koren et al. reported a case of müllerianosis of the urinary bladder, which suggested a metaplastic origin.4 They described a small focus of metaplastic ciliated epithelium of the tubal type in continuity with the urothelium in glandularis cystitis, and these metaplastic glandular cells were immunohistochemically positive for estrogen receptor and progesterone receptor. Therefore, they speculated that müllerianosis can arise through metaplasia of the urothelium in a setting of chronic inflammation, which is similar to this case. Branca and Barresi also speculated that peritoneal mesothelium, also referred to as the secondary müllerian system, may retain the potential to differentiate into tubal, endometrial, and endocervical tissues in the adult. Differential diagnosis of müllerianosis includes cystitis glandularis, cystitis cystica, bladder adenocarcinoma, and carcinoma of the urachus. Definitive diagnosis is established by histopathologic analysis, based on cellular architecture and cytologic findings. Despite the benign nature of bladder endocervicosis, a recent case of adenocarcinoma associated wih bladder endocervicosis has been reported by Nakaguro et al.1 It has also been reported to present as renal colic by Ndokera et al., which after work-up showed a bladder mass and turned out to be müllerianosis.5 Most commonly, müllerianosis has been found in the urinary bladder, but there are cases of it found in other areas including abdominal scars, inguinal lymph nodes, and other regions of the urinary tract.

Müllerianosis is usually managed initially on the way how they present, that is, hematuria work-up for those seen for blood in the urine, analgesia for patients presenting with pain, or receive antibiotics if they present with UTI symptoms. Patients then go for imaging and cystoscopy where the lesion is found and proceed with a bladder tumor resection where the diagnosis is confirmed on histology. Even though müllerianosis has a benign course, it is important to note that it may present with acute renal colic, patients may have lower urinary tract symptoms and more importantly will still need to be worked up to rule out malignancy. Usually after the diagnosis is confirmed, there is no need for follow-up as this is a benign pathology. However, depending on the clinician, a follow-up cystoscopy may be recommended to check for recurrence before discharging the patient. In this case, we will be following up the patient in 6 months time with a cystoscopy before discharging her from our clinic. Abbreviations Used - CT computed tomography - H&E hematoxylin and eosin - MRI magnetic resonance imaging - UTI urinary tract infection Disclosure Statement No competing financial interests exist. Cite this article as: Salada RB, II, Yong D, Ho CSB, Chong YL (2019) Müllerianosis: a case report, Journal of Endourology Case Reports 5:3, 124–127, DOI: 10.1089/cren.2019.0036.

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