Primary malignant lymphoma of the urinary bladder in a dog: longterm remission following treatment with radiation and chemotherapy.

Primary (extranodal) malignant lymphoma limited exclusively to the urinary bladder is an extremely rare disorder in both humans and animals and has to be differentiated from malignant lymphoma cases where a systemic (multicentric) lymphoma has spread to the bladder. We report a case of a 3-year old female spayed mixed breed dog presenting with gross haematuria and dysuria and diagnosed with a primary B-cell high-grade lymphoma of the urinary bladder without involvement of any other site. After treatment with a combination of hypofractionated external beam radiation and cytotoxic chemotherapy, rapid and complete remission of the tumor occurred. At present the dog is alive and has been in remission for 52 months.