Stump Pyometra Secondary to Human Topical Estrogen Hormone Exposure in a Spayed Female Chihuahua.

A 6 yr old female spayed Chihuahua was presented for evaluation of intermittent vulvar discharge, stranguria, and vomiting. This dog had an ovariohysterectomy as a puppy and did not experience any evidence of estrous until 4.5 yr later. The owner had been using a topical hormone replacement therapy (estradiol spray) twice daily for the duration of the dog's clinical signs of 1 yr. On presentation, the dog had truncal alopecia, comedones, enlarged vulva with a malodorous, and purulent discharge. Bloodwork showed a leukocytosis with a neutrophilia, döhle bodies, and moderate toxic changes. An abdominal ultrasound revealed an enlarged uterine stump with a thickened wall, ovoid projection cranially, and echogenic luminal contents. An exploratory laparotomy identified an enlarged cervical stump. Histopathology revealed chronic suppurative vaginitis with endometritis, necrosis, and intraluminal coccoid bacteria. The dog recovered well from surgery. A baseline estrogen level post operatively was measured at 56.4 pg/mL (<50.0 pg/mL for a spayed bitch), at this time, the dog had been separated from the owner for 7 days. After surgery, the clinical signs disappeared, and the dog's dermatologic changes improved. This is the first reported case of stump pyometra following exposure to the owner's topical estradiol replacement medication.

Neurologic complications after melarsomine dihydrochloride treatment for Dirofilaria immitis in three dogs.

Melarsomine dihydrochloride is highly effective against both sexes of adult and L5 Dirofilaria immitis. Common adverse reactions include injection site irritation and reluctance to move. Neurologic complications associated with i.m. injection of melarsomine dihydrochloride for treatment of heartworm disease in 3 dogs are described. Different degrees of neurologic complications have been identified; the pathophysiologic features are unknown. It is speculated that the compound migrates out of the injection site via fascial planes and causes an ascending inflammation along nerve roots. The resulting extradural cord compression secondary to extensive inflammation and necrosis of epidural fat could induce a variety of neurologic deficits. Alternatively, inappropriate injection technique may result in direct contact of melarsomine with neural tissue. A heightened awareness of proper injection technique might prevent the development of most neurologic complications.

The use of cytochemistry, immunophenotyping, flow cytometry, and in vitro differentiation to determine the ontogeny of a canine monoblastic leukemia.

We evaluated the utility of cytochemistry, immunophenotyping, flow cytometry, and in vitro culture with forced differentiation of leukemic cells as diagnostic aids to identify the malignant cell ontogeny in a dog with leukemia. A tentative diagnosis of monoblastic leukemia was established by microscopic examination of Romanowsky-stained blood smears and bone marrow aspirate smears. This diagnosis also was supported by the light scatter signature that identified the blast cells as large, non-granular monocytic cells using a CellDyn 3500 automated hematology analyzer; as well as by the detection of N-butyrate esterase and the lack of choloroacetate esterase or leukocyte peroxidase by cytochemical staining. Subsequently, leukemic cells were isolated from the dog's peripheral blood and placed into tissue culture or cryopreserved. The leukemic cells grew in suspension cultures and proliferated spontaneously for up to 4 days. By day 7, proliferation was negligible. Upon culture with conditioned supernatant using mitogen-stimulated human T cells as a source of cytokines, an increased proportion of cells entered S phase by day 2 of culture; however, proliferation declined markedly by day 4, at which time the cells had apparently differentiated to adherent, vacuolated macrophages. The cytokine-stimulated leukemic cells were positive for the monocyte/macrophage specific markers alpha-1-antitrypsin, alpha-1-antichymotrypsin, lysozyme, CD14, MHC class II, and calprotectin, an antigen found in differentiated macrophages and granulocytes. Despite the strong tendency of the leukemic cells towards monocytic differentiation, our results suggested that they retained some features of a myelomonocytic precursor. These data show that cytochemistry, immunophenotyping, flow cytometry, and in vitro differentiation of canine leukemia cells are useful tools for confirming the lineage of malignant hematopoietic cells.