Primary Urinary Bladder Angiosarcoma with Osteoclast-Like Multinucleated Giant Cells: A Case Report and Literature Review.

BACKGROUND Angiosarcoma is a fatal and aggressive mesenchymal tumor. It occurs in skin, breast, and parenchymal organs. It rarely arises primarily in the urinary bladder. Only 13 cases of primary urinary bladder angiosarcoma have been reported in the English literature. CASE REPORT The patient was a 68-year-old man who presented to the Emergency Department with inability to void. Computed tomography of the abdomen and pelvis showed a urinary bladder mass. Surgical excision of the mass was performed. Pathological examination results were consistent with angiosarcoma. In addition to the unusual location of this tumor, the pathology was different from the previously reported cases in that this case was rich with osteoclast-like multinucleated giant cells. CONCLUSIONS The pathological diagnosis of primary urinary bladder angiosarcoma is challenging. Histological patterns and immunophenotypes are variable. Here, we review all reported cases of primary urinary bladder angiosarcoma, highlight the clinical and morphological features of this malignant neoplasm, and report a unique case of primary urinary bladder angiosarcoma with osteoclast-like multinucleated giant cells.