Dysuria Associated with Non-Neoplastic Bone Hyperplasia of the Os Penis in a Pug Dog

A three-year-old male Pug presented with a three-year history of urolithiasis and repeated urethral obstruction. Biochemical analysis, ultrasonography, and retrograde urethrocystography revealed probable portosystemic shunt and incomplete urethral obstruction due to uric acid ammonium calculi. Enhanced computed tomography (CT) revealed portosystemic shunt and proliferation of the osseous tissue of the os penis, which was surgically removed. Histopathologically, the excised osseous tissue comprised bland lamellar bone without atypia or inflammation. Hyperplasia of the os penis was diagnosed based on the image findings and histopathology. The dysuria improved postoperatively. This is the first report of dysuria associated with non-neoplastic bone hyperplasia of the os penis in a dog. Careful evaluation of the os penis by CT is needed for accurate diagnosis in case of repeated penile urethral obstruction.