Multiple glomus tumors of the urinary bladder in a cow associated with bovine papillomavirus type 2 (BPV-2) infection

We report a case of multiple glomus tumors associated with bovine papillomavirus type 2 (BPV-2) infection in the urinary bladder of a 13-year-old cow suffering from severe chronic enzootic hematuria. Macroscopically, multiple submucosal reddish nodules were seen swelling the vesical mucosa. Histologically, neoplastic proliferation was characterized by the presence of numerous blood vessels. These were lined by normal endothelial cells surrounded by round epithelioid cells with central nuclei, prominent nucleoli, acidophilic cytoplasm, and well-defined cytoplasmic borders. Tumor cells were distributed around open vascular lumina and in perivascular spaces. They were immunohistochemically positive for actin and vimentin and negative for cytokeratins, desmin, and factor VIII-related antigen. On the basis of these findings, this tumor was diagnosed as glomus tumor, a neoplasm not previously reported in cattle and exceedingly rare in animals. BPV-2 DNA was amplified from the formalin-fixed, paraffin-processed tissue specimens obtained by laser capture microdissection. This report widens the spectrum of mesenchymal tumors of the bovine urinary bladder. Finally, the microscopic pattern of tumor described here shares striking morphologic and immunohistochemical similarities with the angiomatous form of glomus tumor known to occur in man.