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Table 1.  

Panel of Immunomarkers and Their Immunoreactivity in IMT, Rhabdomyosarcoma, Myxoid Leiomyosarcoma and Sarcomatoid Carcinoma. The Combined Staining Pattern Helps to Differentiate Between These Entities

Evaluation and Management of a Patient With a Bladder Mass of Uncertain Etiology

Authors: Jens Bedke, MD ; Stephan Buse, MD ; Irene Esposito, MD ; Peter Schirmacher, MD ; Axel Haferkamp, MD ; Markus Hohenfellner, MDFaculty and Disclosures


Summary and The Case


Background: A healthy, parous, nonsmoking, 36-year-old woman consulted her gynecologist for nonspecific bladder pain. Urinary tract infection was ruled out. Vaginal ultrasonography and MRI revealed an undefined tumor between the bladder and the uterus. The patient refused further testing until tumor growth was detected at a scheduled appointment 5 months after presentation. She was referred to a urology department at this time.
Investigations: Physical examination, urine culture, medical history, cystoscopy, MRI, angiography, intraoperative frozen section analysis, and final histology.
Diagnosis: Inflammatory myofibroblastic tumor of the bladder.
Management: Partial cystectomy with complete excision of the tumor from the trigonal and posterior wall of the bladder by median laparotomy.

The Case

A healthy, parous, nonsmoking 36-year-old woman initially consulted her gynecologist with nonspecific bladder pain. Urinary tract infection was ruled out by urinalysis. Vaginal ultrasonography revealed an undefined but well demarcated tumor between the bladder and the uterus. MRI confirmed a sharply defined mass measuring 1.8 × 0.9 × 1.6 cm, which was judged to be benign. The patient refused further testing at this time; however, 5 months later at a scheduled appointment, the tumor had grown to 2.3 × 1.9 cm, as measured by ultrasonography. She was referred to a urology department by her gynecologist.

At presentation to the urology department, the patient had neither gross hematuria nor dysuria. Her urine cultures were negative, and her medical history revealed no exposure to toxic agents, previous abdominal surgery, or trauma. The patient reported two uncomplicated vaginal births. Cystoscopy revealed a nonulcerating mass at the left posterior bladder wall, which appeared to compress the wall from the outside (Figure 1). The left orifice of the ureter was lateralized. All other parts of the bladder mucosa showed no abnormalities or signs of exophytic tumor growth. Bimanual palpation revealed a manipulatable mass between the uterus and the bladder. All other physical findings were unremarkable. MRI confirmed a 2.9 × 2.4 × 2.1 cm tumor (Figure 2) with no signs of intra-abdominal extension or metastatic spread. MRI could not determine the origin of the tumor (bladder, uterus, vagina or ovary). Angiography revealed a hypovascularized tumor with no sign of vascular invasion.

Figure 1. (click image to zoom) Images from cystoscopy. (A) The nonulcerating solid tumor mass is seen at the left lateral bladder wall (white arrows). The mass seems to compress the bladder wall from outside. (B) The orifice of the left ureter is lateralized by the tumor mass (black arrow).

Figure 2. (click image to zoom) Images from sagittal MRI. This image shows the lesion at the posterior-lateral wall of the bladder (white arrows), well demarcated from the surrounding tissue. A clear discrimination of origin of the mass (bladder, uterus, vagina or ovary) is not possible.

Despite the lack of evidence of malignancy, none of the preoperative clinical findings could exclude a malignant tumor or a sarcoma, and confirm a benign nature of the lesion. Furthermore, the bladder could not be distinguished as the origin of the tumor. Transurethral dissection was not initially carried out; instead, open surgery was performed with the intention of preserving the bladder. As malignancy remained a possibility, the patient's informed consent also included radical cystectomy and urinary diversion. The tumor was excised completely from the trigonal and posterior wall of the bladder by median laparotomy (safety margin 1 cm). Intraoperative frozen section analysis did not demonstrate overt malignancy, and a two-stage strategy to preserve the bladder was performed. Radical cystectomy in a second operation was planned if indicated by definitive histology.

Gross examination revealed that the tumor specimen was involved in the entire thickness of the bladder wall. Microscopically, no tumorous infiltration of the perivesical fat or specimen margins was observed. The tumor consisted of a transmural spindle-cell lesion with an inflammatory infiltrate composed primarily of lymphocytes and plasma cells (Figure 3) with scattered eosinophils. The proliferation rate of the spindle cells was below 10%, and the tumor had minimal pleomorphism. One to two mitoses were evident per high-power field. Immunohistochemistry showed that the tumor was positive for vimentin and muscle-specific actin (Figure 3), but negative for desmin, h.caldesmon, protein S100, CD34, epithelial membrane antigen, numerous epithelial markers (cytokeratin 5, cytokeratin 18, cytokeratin AE1/AE3), the broad-spectrum epithelial marker cytokeratin (KL1), and anaplastic lymphoma kinase (ALK). The final histological diagnosis was an inflammatory myofibroblastic tumor (IMT) of the bladder.

Figure 3. (click image to zoom) Images of the patient's inflammatory myofibroblastic tumor. (A) Macroscopic aspect of the IMT showing a whitish-yellow surface with a sharply defined border with the surrounding tissue. (B) Microscopic overview of the lesion within the muscle layer of the bladder (magnification ×12.5; hematoxylin and eosin stain). (C) Microscopy showing a high cellular spindle-cell proliferation with scattered lymphoid nodules and plasma cells (asterisks). Residual smooth muscle cells of the bladder wall (M) can be seen (magnification ×25; hematoxylin and eosin stain). (D) Microscopy of the IMT showing a compact fascicular spindle-cell proliferation with a collagen background (magnification ×200; hematoxylin and eosin stain). (E) Microscopy showing diffuse immunoreactivity of the tumor cells for muscle-specific actin: positive smooth muscle bundles (M) of the bladder wall are stained (magnification ×200; stain for muscle-specific actin). (F) Microscopy showing scattered cells positive for EMA: the tumor cells show no immunoreactivity for EMA (magnification ×400; stain for EMA). Abbreviations: EMA = epithelial membrane antigen; IMT = inflammatory myofibroblastic tumor.

The patient's postoperative follow-up was uneventful; her catheters were removed 3 weeks after surgery, her functional bladder capacity was 200-350 ml, and her micturition frequency was 5.[7] times per day. No residual urine, incontinence, or tumor recurrence arose during a follow-up period of 18 months.

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