Intramural leiomyoma of the urinary bladder

Týp Araþtýrmalarý Dergisi 2004: 2 (3): 37 - 40
OLGU SUNUMU
Intramural leiomyoma of the urinary bladder:
Diagnostic value of CT vs US
Aylin Yücel, Alpay Haktanýr, Ramazan Albayrak, Murat Acar, Bumin Deðirmenci
Department of Radiology, Afyon Kocatepe University School of Medicine, Afyon, Turkey
Özet
Mesane intramural leyomyomunda CT ve US
bulgularýnýn tanýya katkýsýnýn karþýlaþtýrýlmasý
Mesane leiyomyomlarý, nadir, benign mezenkimal
tümörlerdir. Burada intramural leiyomyom saptanan bir olguyu sunuyor ve sonografi ile tanýdaki
güçlükleri ve bilgisayarlý tomografinin gerekliliðini
tartýþýyoruz.
Anahtar kelimeler: Leiyomyom, mesane, bilgisayarlý
tomografi, ultrason.
Intramural leiomyoma of the urinary bladder:
Diagnostic value of CT vs US
Abstract
Leiomyomas of the urinary bladder are rare benign
mesencymal tumors. We report a case of intramural
leiomyoma of the urinary bladder and discuss difficulties in diagnosis with sonography and necessity of
computed tomography.
Key words: Leiomyoma, bladder, computed tomography, ultrasound.
This paper has been presented as a scientific poster at the "25. Ulusal
Radyoloji Kongresi" (27-31 October 2004) in Antalya, Turkey.
Corresponding author:
Aylin Yücel, MD, Assoc. Prof.
Department of Radiology, Afyon Kocatepe University School of
Medicine, 03200, Afyon-Turkey
Phone: +90 272 213 67 07
Fax: +90 272 214 49 96
E-mail: [email protected]
Leiomyomas of the urinary bladder are rare benign
mesencymal tumors (1,2). The locations of these tumors
are classified into three types: endovesical (63%), intramural (7%), and extravesical (30%) (1-5). According to
the location, they may be asymptomatic and discovered
incidentally by radiologic imaging or may cause irritative or obstructive symptoms (1-3). We report a case of
intramural leiomyoma of the urinary bladder, briefly
review the literature, and discuss difficulties in diagnosis with sonography (US) and necessity of computed
tomography (CT).
Case Report
A 32 year-old-man presented with two days history of
nausea, vomiting, low back pain, dysuria and 39 degree
body temperature. In physical examination, costovertebral angle tenderness was positive. In urine analysis, 12 white cells, 2-3 red cells, a few bacteria and uric acid
crystals were detected.
Gray-scale US revealed a hypo-anechoic mass, which
was located in the anterosuperior wall of the urinary
bladder. It was 3x2x2 cm sized, ovoid shaped, smoothly and hyperechogenic contoured mass extending out of
the wall (Figure 1A). This appearance seemed like a
vesical diverticulum. However, color Doppler US
(CDUS) demonstrated poor, low peak systolic flow
arterial vascularization in the mass (Figure1B).
Non-enhanced CT scan revealed homogeneous, hyperdens, intramural solid mass with benign nature, growing
extravesically rather than intravesically and showed
sharply angled interfaces with the bladder wall (Figure
2A). CT scan showed the mass without significant
enhancement (precontrast value: 83.19 HU, postcontrast value: 84.96 HU) (Figure 2B).
Trans urethral resection (TUR) of the lesion was performed and histopathological diagnosis was leiomyoma. The treatment of urinary infection was also admin-
38
Intramural leiomyoma of the bladder: CT vs US
Yücel at all
Figure 1A: Gray-scale US shows a hypo-anechoic mass mimicking vesical diverticulum.
Figure 1B: CDUS demonstrates low flow arterial vascularization
in the mass.
istrated with antibiotics.
Discussion
Less than 5% of all primary bladder tumors are
mesothelial in origin, and the majority of these are
malignant (5,6). Nevertheless, leiomyoma is the most
common benign mesenchymal tumor of the urinary
bladder (2,3,5,6). Approximately three-quarters of cases
occur in women between ages of 30 and 60. It has been
suggested that estrogen may contribute to the growth of
leiomyoma (3). It was intresting that in the review of the
literature, most of case reports of leiomyomas, was
from Japan literature (7).
A quarter of these tumors are diagnosed in asymptomatic patients usually by US (4). The most common
symptoms are obstructive voiding symptoms (49%),
followed by irritative symptoms (38%), and hematuria
(11%) (1,3-5,6). Of all types of bladder leiomyomas,
the endovesical form is the most common and are most
Intramural leiomyoma of the bladder: CT vs US
Yücel at all
39
Figure 2A: Non-enhanced CT scan reveals hyperdens, intramural solid mass growing extravesically.
Figure 2B: Enhanced CT scan shows the mass without significant enhancement.
likely to be symptomatic because they protrude into the
lumen of the bladder (2,3,5). However, intramural form
is the rarest and causes symptoms depending on its size
and location (2). Our case had a relatively small intramural leiomyoma with urinary infection symptoms.
Although he had urinary infection like a symptom of the
leiomyoma, we believed that the lesion was detected
incidentally with urinary system US.
Excretory urography shows a filling defect in the urinary bladder (1,5). The appearence of these tumors on
US, mainly those with endovesical growth, is very characteristic. They appear as a homogenous smooth mass
with peripheral hyperechogenicity (4). We could not
diagnosed the mass easily, because of its location. It
was seen extravesically rather than intramural or intravesically. It had hyperechogen margin, and its internal
echogenicity was very low like a cystic lesion. We
thought first that it could be a diverticulum of the bladder. But under CDUS examination, hypovascularity
with low arterial flow pattern in the lesion was seen and
40
Intramural leiomyoma of the bladder: CT vs US
Yücel at all
it was considered as solid benign tumor.
CT scans can clearly demonstrate the location of these
tumors (4,5). It was reported previously that CT is
inadequate to identify the liquid or solid nature of the
lesion, and its relationship to adjacent structures and its
mobility (1,4,5). Contrary to this, in our diagnosis, CT
was very helpful to demonstrate the characteristics and
location of the lesion. It was hyperdens in non-contrast
images, which could be due to tumor contents including
intense collagenization and hyalinization. In contrast
enhanced images, there was no significant enhancement
in the lesion. This was correlated with poor vascularisation in CDUS.
Magnetic resonance imaging can differentiate mesenchymal tumors from the more common transitional cell
tumors and even their malignant counterpart
leiomyosarcoma (2). In general, it is homogeneous and
intermediate signal intensity on T1-weighted images,
and heterogeneous low signal intensity in T2-weighted
images (1,8,9).
Malignant transformation of the bladder leiomyomas
has not been reported (3). No imaging technique can
safely exclude malignancy, so histopathological characterization should always be attempted prior to invasive
therapeutic procedures (4). TUR is a reasonable initial
choice of diagnosis and also treatment in patients with
relatively small tumors (3). In our case, tumor size was
small and TUR was performed.
In conclusion, although it is seen very rare, leiomyoma
should be thought first in differential diagnosis of the
benign lesions of the urinary bladder. And in the diagnostic algorithm, CT should be performed after US as a
complementary imaging modality.
References
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