Benign bladder tumors consist of myomas, fibromyomas, leiomyomas, rhabdomyomas, fibromas, angiomas, myxomas, and osteomas. The most common histologic type of benign bladder tumor is leiomyoma which does not have any predilection for gender or age [1
]. In 1994, Goluboff et al. observed a higher incidence of leiomyoma in women of third to fifth decade of life with a mean size of 5.5
]. These lesions may be categorized as endovesical, extravesical, or intramural [7
]. Endovesical masses have been mostly recognizable (63%); possibly due to its characteristic bulging into the bladder which induced irritative symptoms and forced the patient to seek medical treatment. The two other types of mass occur with a frequency of 30% and 7% for extravesical and intramural, respectively, [1
]. Epitheloid leiomyoma is a rare subtype with uterus as a common site of involvement. Variations of leiomyoma in uterus include lipoleiomyomas, cellular leiomyomas, bizarre (symplastic) leiomyomas, and epithelioid leiomyomas [6
]. Urinary symptoms were often observed in this tumor; for example, Goluboff et al. reviewed all reported cases of leiomyoma of the bladder in the English literature and indicated that obstructive symptoms were the most frequent (49%) presenting patient complaint [8
]. On the other hand, Knoll et al. observed irritative symptoms as the most frequent presenting symptoms [9
]. After a comprehensive history, a complete physical examination could be helpful, due to the fact that palpable lesion was encountered in 57% of women at bimanual examination.
In imaging such as intravenous urography (IVU) or cystourethrogram usually a smooth filling defect in the bladder was identified. Abdominal ultrasound may be helpful in differentiating cystic lesion from solid one [1
]. Fernandez and Dehesa investigated the various radiographic measures used in demonstrating these benign tumors to determine which method was the most fruitful for the physician preoperatively. They noted computed tomography (CT) scan to be beneficial for precisely locating the tumor but inadequate for identifying its relationship to the adjacent bladder mucosa or vaginal wall due to its fixed axial plane. They advocated transvaginal ultrasound with production of better definition of the mass. Leiomyomas of the bladder are demonstrated sonographically as solid smooth-walled lesions with many internal echoes and with an underlying homogeneous texture of medium echogenicity.
These tumors are easily visualized in cystoscopy that covered the normal bladder mucosa [10
]. In histopathology, bladdrer leiomyoma may be clearly differentiated from leiomyosarcoma. Leiomyomas appear as whitish gray round to ovoid nodules with spiral appearance of smooth muscle fibers. They are firm and rubbery in consistency [8
]. In contrast, leiomyosarcoma has little mitotic activity and usually has a large quantity of myxoid intracellular material with invasion to the muscularis propria. There are no reports of malignant degeneration of leiomyoma [8
The pathophysiology of leiomyoma of the bladder is unclear. However, four major theories have been proposed for this tumor: (1) inflammatory resection of the bladder wall to an infection of the bladder musculature; (2) metaplastic reaction around the perivascular walls from vascular inflammation of the bladder; (3) neoplasm controlled by hormonal influences; (4) dysontogenesis: the result of embryologic rest within the bladder wall developing into a smooth muscle tumor. Despite of mysterious cause of it, the diagnostic examination and surgical management are easy [1
The treatment of this rare condition is primarily determined by its size and anatomic location [1
]. In Goluboff's review, 62% were treated by open resection, whereas 30% were removed transurethral [8
]. In patients with large endovesical tumors, extravascular tumor, or intramural lesions open resection is a good option and does not require a second procedure. Patient becomes asymptomatic after surgical excision because of low reoperation rate, absence of recurrence, and excellent prognosis of leiomyoma [1
In our patient, irritative voiding symptoms were predominant and intramural lesion was diagnosed by imaging modalities. The normal bladder mucosa over the mass confirmed intramural situation of lesion. A straightforward partial cystectomy was performed for her.