Leiomyoma represents the largest subgroup of benign mesenchymal tumors that may arise anywhere within the genitourinary tract. Usual presenting symptoms include voiding symptoms such as obstruction and irritation. It can be diagnosed by careful physical examination assisted with ultrasound and endoscopic evaluation, but the confirmatory diagnosis is always histological. Bladder-conservative surgery is usually contemplated as the treatment of choice, be it transurethral resection or open surgery. This can include partial cystectomy due to the benign nature of the disease. Although the occurrence of this tumor is rare, it should be suspected with any urinary bladder tumor presenting with benign features. The prognosis is good with bladder preservative protocols.
Bikash Bawri, Rajeev T Puthenveetil, Saumar J Baruah, Sasanka K Barua, Puskal K Bagchi
Submitted: September 9, 2011
Accepted for Publication: November 9, 2011
KEYWORDS: Leiomyoma; Genitourinary tract; Obstruction; Partial cystectomy
CORRESPONDENCE: Bikash Bawri, MD, RK Singh Apartment, House No 54, Ashram Road, Kasturba Nagar, Ulubari, Guwahati-781007, Assam, India ().
CITATION: UroToday Int J. 2012 Feb;5(1):art 83. http://dx.doi.org/10.3834/uij.1944-5784.2012.02.01
Benign mesenchymal tumors make up 1 to 5% of all bladder neoplasms, with leiomyoma representing the largest subgroup of these benign tumors (0.04 to 0.5%) [1,3]. A leiomyoma is a benign, smooth muscle tumor most often located in the uterus or gastrointestinal tract. However, these tumors may arise anywhere within the genitourinary tract and are usually asymptomatic unless urinary tract function is affected . They are predominantly found in women, although men can also be affected. Approximately 250 cases have been reported to date, including patients who had leiomyoma in a urethral location . Typically, it occurs in the fourth and fifth decades of life. The most common presenting complaints are urinary voiding symptoms, such as obstruction and irritation. Surgery is the standard treatment, and the surgical approach depends on tumor size and localization at the bladder wall. Prognosis is good due to the benign behavior of these lesions. We describe a case of urinary bladder leiomyoma in a young woman with acute urinary retention. Although not initially suspected, the diagnosis of urinary bladder leiomyoma was subsequently, histologically confirmed.
A 27-year-old woman presented with acute urinary retention and a 7-month history of urgency, urge incontinence, and intermittent hematuria associated with dull, intermittent, lower abdominal pain. The patient had similar episodes of acute retention during this period, which subsided after some movement by the patient, similar to the ball-valve effect. There was no history of weight loss or other constitutional symptoms. The physical examination was normal, except for anemia and a freely movable, solid mass in the suprapubic region, which was not tender. It was firm, smooth surfaced, and well defined. Urinalysis demonstrated significant red blood cells (RBCs), and all other laboratory investigations were normal, except for the anemia. The abdominopelvic ultrasound (US) demonstrated a solid mass of 80.5 mm by 65.5 mm inside the urinary bladder. Computerized tomography (CT) confirmed the solid mass as heterogeneously poor. It measured 61 by 80.7 by 92.3 mm, rising from the right anterolateral aspect of the bladder where there was bladder-wall thickening measuring up to 16.9 mm. The lesion was clear from the bilateral vesicoureteric junction (VUJ), and perivesical fat appeared clear with bilateral, mild hydroureteronephrosis and no lymphadenopathy (Figure 1).
On cystoscopy, an anterolaterally located, intraluminally protruding solid mass covered by normal bladder mucosa was seen (Figure 2). Both the ureteric orifices were normally located and free of the tumor. Upon suspicion of malignancy, the patient underwent pelvic exploration, which revealed an intramural, capsulated, solid mass arising from the anterolateral wall of the bladder. It was well capsulated, its margins were distinct, and it was protruding intravesically. The overlying mucosa was smooth, and both ureteric orifices were typically uninvolved. Partial cystectomy was done with a 2 cm bladder margin around the pedicle of the mass. The operative room time was 80 minutes, with an intraoperative blood loss of approximately 100 ml (Figure 3).
Pathological examination revealed a 95 by 90 by 55 mm multinodular, encapsulated mass with a light brown external surface. The cut surface was grey-white and whorled, with mucoid and hemorrhagic areas. Microsections showed interlacing fascicles of smooth-muscle bundles, with mild, cellular atypia and areas of myxoid change, suggestive of leiomyoma of the urinary bladder (Figure 4). There was no invasion of the bladder wall, and the margins were uninvolved by the tumor, with no evidence of malignancy.
The patient had an uneventful recovery following the procedure. The patient remained well at a 1-year follow-up, and no further urinary frequency and hematuria were noted.
Leiomyoma originates from smooth-muscle bundles, and connective tissue surrounds it. Therefore, it can arise in any organ that contains this tissue. The most common localizations are the skin, womb, retroperitoneum, and genitourinary and gastrointestinal tracts [5,7,9]. In the genitourinary tract, it is most frequent in the kidney and bladder, especially at the trigone and bladder neck [7,9,10]. A review by Goluboff et al. of 37 cases in the English literature showed that the mean patient age was 44 years and that 76% of patients were women .
The genesis of this lesion remains a mystery; however, there are multiple theories that try to explain this question : 1) Blum’s irritative-inﬂammatory theory, which suggests the presence of chronic inﬂammatory stimuli over the smooth muscle, 2) Piegel’s disontogenic theory, which suggests its origin comes from embryogenic rests of Müller and Wolffian ducts, 3) vascular-irritative theory, and 4) Lips-Chutz’s theory, which suggests its origin is secondary to an endocrine disorder, with estrogen and progesterone having a primary role. This theory supports peak incidence in females when fertile, and the presence of steroidal ovarian receptors on the tumor .
Macroscopically, these are round or oval tumors with an elastic consistency and irregular surface. The size varies, with reports of tumors as big as 30 cm, especially in extravesical localization [9,10]. In bladder lesions, the localization is submucosal in 63%, and at cystoscopy, we can see a sessile or pedunculated lesion covered by normal mucosa. The subserosal localization represents 11 to 30% of the cases, having a characteristic pedicle that bounds it with the bladder. The intramural localization is less frequent and represents 7 to 17% of the cases, with a well-encapsulated tumor in the bladder wall [3,6,9]. Leiomyomas can remain asymptomatic for many years, reaching considerable size, unless they affect the normal function of the lower urinary tract . Endoluminal tumors are symptomatic, presenting with urinary tract infections, hematuria, irritative symptoms (especially at the bladder neck), or obstructive symptoms, causing even acute bladder outlet obstruction secondary to a valve effect [5,6,9,10], as in our case. Intramural and subserosal tumors are, in general, asymptomatic and the diagnosis is incidental. At cystoscopy, submucosal tumors appear as a sessile or pedunculated lesion covered by normal mucosa, but it could be normal if the tumor is intramural or subserosal. The same situation can occur in the intravenous pyelography (IVP), showing a ﬁlling defect in the bladder wall if the lesion is submucosal. Ultrasound allows us to deﬁne the solid or cystic nature of the lesion, showing, in these cases, a solid, smooth wall lesion with homogeneous echoes. Transvaginal ultrasound is an excellent option in female posterior bladder-wall tumors in subserosal localization [6,9]. Computed tomography gives us information about the size, position, and relationship between the tumor and bladder wall. An MRI shows a leiomyoma with an intermediate signal on T1 weighted images, with contrast between the tumor and the urine, which has a low-signal intensity. Nevertheless, imaging tests add important data that suggest the benign nature of these tumors, like the presence of a well-circumscribed lesion with homogeneous density, poor enhancement with contrast media, and normal, perivesical fat. There is no test that allows us to differentiate a leiomyoma from leiomyosarcoma; therefore, pathologic diagnosis is mandatory . Leiomyomas are firm and rubbery in consistency, appear as whitish-gray, round to ovoid nodules with a spiral appearance of smooth-muscle fibers, and eosinophilic cytoplasm with less than 2 mitotic ﬁgures per high-power ﬁeld. They are surrounded by a variable amount of connective tissue, and there is no necrosis or cellular atypia .
In a literature review by Silva-Ramos et al., 90 bladder leiomyomas where analyzed, 28 of which where biopsied before the deﬁnitive treatment. All samples obtained with a Tru-Cut needle and transurethral resection (TUR) were diagnostic, whereas the cold-cup biopsy samples showed a 50% false negative. Fine-needle aspiration biopsy was the least useful diagnostic tool .
The treatment depends on the tumor size, localization, and relationship with the bladder wall . Surgery is indicated because of the potential growing capacity of these tumors . Given the benign nature of these lesions, the surgery must be as conservative as possible. Submucosal tumors can be managed by transurethral resection, noting the size is an important issue. Subserosal and huge submucosal lesions can be managed by enucleation or with partial cystectomy. In Goluboff’s review of the literature, 62% were treated by open resection, whereas 30% were removed by transurethral resection . Prognosis is good and recurrence is rare if the resection is adequate; therefore, it seems unnecessary to establish follow-up protocols. However, Lake, in 1981, described what is, to date, the only case of a leiomyoma with malignant degeneration . The laparoscopic approach is an excellent option for tumors located at the mobile wall of the bladder, allowing an easy and safe procedure. Bladder-wall edges are simple to identify, especially if simultaneous cystoscopic control is used, which adds the option of resecting the tumor with the resectoscope .
Leiomyoma of the urinary bladder is actually not an uncommon disease for middle-aged women presenting with obstructive and irritative voiding symptoms. Careful physical examination and ultrasound may occasionally discover it. It is readily and successfully treated with TUR or open surgery, in most cases. It should be considered for its successfully diagnosable and treatable nature in any pelvic mass involving the bladder wall. Although only 250 cases have been reported to date, our case presented at a very young age, with typical symptoms of ball-valve-type acute retention with a large-sized leiomyoma.
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