A 68-year old man was admitted to our clinic in November 2006 because of an isolated episode of gross hematuria. Intravenous urography, performed a few days later, identified a right-sided bladder diverticulum measuring 5 cm in the largest diameter, with no wall irregularities, or filling defects, which would point to the presence of neoplasm. In October 2007, after a few additional episodes of painless gross hematuria, the patient returned to the clinic and was hospitalized for further diagnostic procedures. Cystoscopy revealed a diverticulum over the right side of the urinary bladder. Intravenous urography showed a large bladder diverticulum measuring 7 × 7 cm with a 3 cm stone within (Figure ). The diverticulum was compressing the bladder and dislocating the right ureter towards the central line. Prostate was moderately enlarged. Cystography confirmed the diagnosis of lithiasis of the bladder diverticulum. Diverticulectomy was performed and intraoperative tumorous-like tissue surrounding the stone was found. The specimen was sent to pathology.
Figure 1 Radiographic, macroscopic and histological findings. A) Intravenous urography showing large bladder diverticulum, measuring 7 × 7 cm, with 3 cm stone-like component within (arrow). Diverticulum was compressing the bladder and dislocating right (more ...)
Grossly, the bladder diverticulum exhibited tan to brown mucosa with a 3.2 × 3.5 × 1.8 cm greyish, solid tumor with gritty, firm center (Figure ). Microscopically, the tumor was composed of atypical, oval to spindle shaped cells with prominent mitotic activity, in some parts rimmed with lacelike osteoid (Figure ). In central parts of the tumor, the osteoid was mineralized and deposited as irregular trabeculae with malignant osteocytes within lacunae (Figure ). There were 20 slides of the tumor in bioptic material and these were thoroughly examined, but no epithelial component was found. Immunohistochemistry was performed with primary antibodies to cytokeratin (CK), cytokeratin 7 (CK 7), cytokeratin 20 (CK 20), epithelial membrane antigen (EMA), carcinoembryonic antigen (CEA), smooth muscle actin (SMA) and S-100 protein (all DAKO, Denmark). Tumor cells showed negative reaction for CK, CK 7, CK 20, EMA and CEA, which confirmed the absence of epithelial component, specifically the urothelial one. Reaction to SMA was positive, and reaction to S-100 protein was only focally positive. The diagnosis of osteosarcoma was established. The tumor invaded the whole thickness of diverticulum wall with no extension to the perivesical fat. The urothelium adjacent to the tumor showed areas of squamous metaplasia with no cytologic atypia.
Six months postoperatively the patient was alive and well. Extensive clinical examination revealed no signs of other primary tumor.
In April 2009, the patient was hospitalized again due to macrohematuria. A CT scan revealed extensive tumorous intrapelvical mass (Figure ) which was designated as unresectable.
Figure 2 Radiographic and autopsy findings. A) CT scan showing large intrapelvical tumor. B) The macroscopic view of the intrapelvical tumor at autopsy. C) Metastatic nodules in myocardium. D) Intrapelvical tumor found at autopsy histologically showed picture (more ...)
Patient died in July 2009, 2 years and 8 months after the initial symptoms had occurred. The autopsy revealed a large tumor of urinary bladder, measuring 29 × 26 × 18 cm, filling the pelvis, with extension to abdomen (Figure ). There were 15 slides of primary tumor in autopsy material and again, no epithelial component was identified. Metastases to lungs, heart and liver were found. There were numerous metastatic nodules in lungs, three nodules in myocardium (Figure ) and one nodule in liver. All nodules were histologically confirmed to be metastases of the primary osteosarcoma of the bladder diverticulum (Figure ).