Endometrial venous aneurysms in three New Zealand white rabbits

Hematuria in rabbits has been associated with uterine adenocarcinoma, uterine polyps, renal infarction, urolithiasis, cystitis, bladder polyps, and pyelonephritis. Three adult female New Zealand White rabbits (Oryctolagus cuniculus) developed apparent hematuria, as suggested by blood in their excreta pans. They had been immunized with antigen-adjuvant emulsions, but had uneventful clinical histories. Physical examination disclosed no abnormalities, and laboratory tests, including hematology, serum chemistries, urinalyses, urine cultures, ultrasonography, and intravenous pyelography disclosed mild anemia, hematuria, and proteinuria in two of the rabbits. Antibiotic therapy failed to alleviate clinical signs. Two rabbits were euthanized because of persistent urogenital bleeding and the third rabbit underwent exploratory laparotomy and ovariohysterectomy. Multiple endometrial venous aneurysms were present in the uteri of all rabbits and urogenital bleeding was attributed to episodic bleeding from these lesions. Varices and aneurysms of uterine subserosal and myometrial venous plexuses, but not of endometrial vessels in women have been reported. To our knowledge, endometrial venous aneurysms have not been reported in animals previously. Our findings indicate that the differential diagnoses for sporadic apparent hematuria in female rabbits should include endometrial aneurysms.