Bilateral caudal maxillectomy for resection of tumors crossing palatal midline and use of the angularis oris axial pattern flap for primary closure or dehiscence repair in two dogs.

OBJECTIVE: To describe the technique and outcomes for bilateral caudal maxillectomy for resection of large caudal maxillary tumors crossing palatal midline in two dogs. STUDY DESIGN: Clinical case report. ANIMALS: Two client-owned dogs. METHODS: Two client-owned dogs with primary caudal maxillary tumors, a poorly differentiated sarcoma, and a multilobulated osteochondrosarcoma. Bilateral caudal maxillectomies were performed for curative-intent resection of these tumors. The angularis oris axial pattern flap was used for primary closure in one dog and for dehiscence repair in the other. RESULTS: Both tumors were resected with complete histologic margins. The defects were closed with local buccal mucosal flaps, with or without a unilateral angularis oris flap. Esophagostomy tubes were placed at time of surgery to bypass oral feeding. Incisional dehiscence and subsequent oronasal fistula formation occurred as a postoperative complication in both dogs (3 and 10 days, respectively). Both were successfully repaired with a combination of local buccal mucosal flaps and the angularis oris flap. Both dogs had good functional outcome and quality of life after recovery from revision surgery. CONCLUSION: Bilateral caudal maxillectomy allowed resection of caudal maxillary tumors crossing palatal midline, with good function and quality of life after recovery in 2 dogs. CLINICAL SIGNIFICANCE: Good outcomes including complete resections are achievable with bilateral caudal maxillectomy despite complications. Local mucosal and axial pattern flaps can be used for dehiscence repair.

Hemipelvectomy: outcome in 84 dogs and 16 cats. A veterinary society of surgical oncology retrospective study.

OBJECTIVE: To report clinical findings, perioperative complications and long-term outcome in dogs and cats that had hemipelvectomy surgery for treatment of neoplasia. STUDY DESIGN: Multi-institutional retrospective case series. ANIMALS: Dogs (n = 84) and cats (16). METHODS: Medical records (January 2000 to December 2009) of dogs and cats that had hemipelvectomy at participating institutions were reviewed. Postoperative progress and current status of the patient at the time of the study was determined by either medical record review, or via telephone contact with the referring veterinarian or owner. RESULTS: Complications were infrequent and usually minor. Hemorrhage was the main intraoperative complication; 2 dogs required blood transfusion. One dog developed an incisional hernia. In dogs, hemangiosarcoma had the worst prognosis with a median survival time (MST) of 179 days. MST for chondrosarcoma (1232 days), osteosarcoma (533 days), and soft tissue sarcoma (373 days) were not statistically different. Median disease-free interval (DFI) for local recurrence of all tumor types was 257 days. Cats had 75% survival at 1 year, which was significantly longer than dogs. CONCLUSIONS: Survival times for most tumor types can be good, but surgical margins should be carefully evaluated to ensure complete tumor removal. Adjuvant therapies may be advisable particularly for dogs to reduce rates of local recurrence or distant metastasis.

Prolonged survival in an aged Labrador retriever with a metastatic insulinoma.

This case report highlights an unusually prolonged, asymptomatic, disease-free interval in an aged male Labrador retriever that underwent partial pancreatectomy for a functionally active pancreatic insulinoma with histologically confirmed hepatic metastasis. The patient developed pancreatitis and nonseptic suppurative peritonitis 24 hr after surgical resection of the insulinoma and was managed medically until discharge. Three mo after surgery, the dog was diagnosed with exocrine pancreatic insufficiency (EPI) that was effectively managed with parenteral pancreatic enzymes. Due to normal glucose levels 3 mo postsurgically, liver samples from the initial surgery were resubmitted for immunohistochemistry. Results confirmed insulinoma metastasis with insulin expression. Ten mo postsurgically, the blood glucose was normal and serum insulin levels were slightly above the upper reference limit. The first hypoglycemic episode was documented 23 mo postoperatively, which was effectively managed with prednisone. The cause for the prolonged disease remission and survival was unknown, but was possibly a result of pancreatitis and peritonitis, partial spontaneous regression of metastatic lesions, or idiopathic. Despite life-threatening postoperative complications, this patient enjoyed a profoundly longer than expected survival. This case highlights the importance of removing the primary tumor (insulinoma) despite the presence of metastatic disease.

Partial ulnar ostectomy, stereotactic body radiation therapy, and palliative radiation therapy as local limb sparing treatment modalities for ulnar tumors in dogs.

Background: Information on dogs that undergo limb preserving local treatment for ulnar tumors is currently limited. Objective: To describe the clinical characteristics and outcomes in dogs that underwent partial ulnectomy or radiation therapy (RT) for ulnar bone tumors, and to evaluate potential risk factors for outcomes as well as pre-treatment factors for association with treatment modality selected. Animals: Forty client-owned dogs that underwent partial ulnectomy or RT for an ulnar tumor from July 2006 to July 2021. Methods: The medical records database from a single institution were retrospectively reviewed, and data were recorded and analyzed. Results: Radiation therapy was performed in 24 dogs, with 12 stereotactic body RT (SBRT) and 12 palliative RT (PRT) plans, and partial ulnectomy was performed in 16 dogs. Biomechanical complications occurred in 6/12 (50%) dogs that underwent SBRT, 6/12 (50%) dogs that underwent PRT, and 3/16 (18.8%) dogs that underwent ulnectomy. The majority of dogs had a good functional outcome following partial ulnectomy, and no dogs required surgical stabilization of the carpus even with lateral styloid process excision. Pathologic fracture occurred in 4/12 (33.3%) dogs following SBRT and 5/12 (41.7%) dogs following PRT. Local progression or recurrence was documented in 5/12 (41.7%) dogs that underwent SBRT, 2/12 (16.7%) dogs that underwent PRT, and 2/16 (12.5%) dogs that underwent ulnectomy. The overall median survival time was 198 days, and factors that were significantly associated with improved survival time included adjuvant chemotherapy administration and partial ulnectomy as local treatment method for dogs that received chemotherapy. Clinical relevance: Both RT and ulnectomy were effective and well tolerated local treatment modalities for dogs with ulnar tumors.

A retrospective study of canine oral extramedullary plasmacytoma over a 15-year period (July 2004-July 2019): Treatment, histologic parameters and clinical outcomes.

A total of 45 cases of canine oral extramedullary plasmacytomas (EMPs) presented to a tertiary referral institution over a 15-year period were examined. Histologic sections of 33 of these cases were examined for histopathologic prognostic indicators. Patients underwent variable treatment including surgical intervention, chemotherapy and/or radiation therapy. Long term survival was observed in the majority of dogs with a median survival time of 973 days (2-4315 days). However, almost 1/3 of dogs had progression of plasma cell disease, including two cases with myeloma-like progression. Histologic characterization of these tumours did not reveal criteria to predict tumour malignancy. However, cases without tumour progression did not exceed 28 mitotic figures in ten 400× fields (2.37 mm2 ). All cases with tumour related death showed at least moderate nuclear atypia. Oral EMPs may represent a local manifestation of systemic plasma cell disease or singular focal neoplasia.

Gel formulation containing mixed surfactant and lipids associating with carboplatin.

The interaction of amphiphilic molecules such as lipids and surfactants with the hydrophilic drug carboplatin was investigated to identify suitable self-assembling components for a potential gel-based delivery formulation. (1) H-NMR Studies in sodium bis(2-ethylhexyl) sulfosuccinate (aerosol-OT, AOT)-based reverse micelles show that carboplatin associates and at least partially penetrates the surfactant interface. Langmuir monolayers formed by dipalmitoyl(phosphatidyl)choline are penetrated by carboplatin. Carboplatin was found to also penetrate the more rigid monolayers containing cholesterol. A combined mixed surfactant gel formulation containing carboplatin and cholesterol for lymphatic tissue targeting was investigated for the intracavitary treatment of cancer. This formulation consists of a blend of the surfactants lecithin and AOT (1 : 3 ratio), an oil phase of isopropyl myristate, and an aqueous component. The phases of the system were defined within a pseudo-ternary phase diagram. At low oil content, this formulation produces a gel-like system over a wide range of H(2) O content. The carboplatin release from the formulation displays a prolonged discharge with a rate three to five times slower than that of the control. Rheological properties of the formulation exhibit pseudoplastic behavior. Microemulsion and Langmuir monolayer studies support the interactions between carboplatin and amphiphilic components used in this formulation. To target delivery of carboplatin, two formulations containing cholesterol were characterized. These two formulations with cholesterol showed that, although cholesterol does little to alter the phases in the pseudo-ternary system or to increase the initial release of the drug, it contributes significantly to the structure of the formulation under physiological temperature, as well as increases the rate of steady-state discharge of carboplatin.

Pericardial free patch grafting as a rescue technique in surgical management of right atrial HSA.

A 7 yr old, neutered female vizsla underwent an exploratory thoracotomy after diagnosis of recurrent hemorrhagic pericardial effusion and a right auricular mass. Staging tests were negative for metastasis. The patient underwent a right, fourth intercostal thoracotomy, subtotal pericardectomy, right auricular mass excision, and pericardial free patch graft. The patient experienced blood loss during surgery, which required a packed red blood cell transfusion. The patient experienced transient arrhythmias postoperatively, but was discharged from the hospital 48 hr later. Histopathologic diagnosis of the mass was hemangiosarcoma. The patient was treated with carboplatin single-agent chemotherapy and palliative radiation therapy. The patient died at home, presumably from metastatic disease 260 days postoperatively. Surgical mass removal or debulking along with pericardial free patch grafting may be considered as palliative treatment options for dogs diagnosed with right auricular masses. In this case report, other techniques failed to repair the defect in the heart and a free patch graft offered a good rescue procedure with a favorable outcome without the need for inflow and outflow occlusion when used in conjunction with adjunctive therapies.

Nasal Smooth Muscle Hamartoma in a Dog: a Novel Subtype.

A 3-year-old, female spayed, Pug-cross dog presented with a 2-year history of nasal congestion and focal facial deformity. Complete surgical excision was elected following nasopharyngoscopy, endoscopic biopsy and subsequent computed tomography (CT) scan. Nasopharyngoscopy revealed a friable, polypoid mass of the right nasal conchae occluding the right nasal passage. Biopsies of the mass showed expansion of the submucosa by dense bundles of well-differentiated smooth muscle cells that were strongly immunoreactive for ⍺-smooth muscle actin and desmin. Post-procedure CT revealed a large space-occupying mass in the nasal cavity with minimal lysis of the adjacent calvarium. Histology following complete excision confirmed the results obtained on the initial endoscopic biopsy. The final diagnosis was smooth muscle hamartoma.

A Contemporary Retrospective Study of Survival in Dogs With Primary Lung Tumors: 40 Cases (2005-2017).

Objective: To report the median survival time in a contemporary cohort of dogs with primary lung tumors and intrathoracic nodal metastasis. Design: Retrospective Case Series. Animals (or sample): Dogs with primary lung tumors treated with lung lobectomy and lymph node biopsy. Procedures: The medical record database at Colorado State University was queried for dogs with primary lung tumors from January 1, 2005 to December 31, 2017. Patients were identified for inclusion if they had lung lobectomy and an intrathoracic lymph node biopsy performed. The median survival time (MST) for lymph node positive (LN+) and negative dogs (LN-) was calculated as well as the MST in dogs that did or did not receive adjuvant chemotherapy. Differences were compared between groups with significance set at p < 0.05. Results: The MST in LN+ dogs (n = 11) was 167 days which was not statistically different from LN- dogs (n = 29) at 456 days (p = 0.2407). No significant difference in the MST in LN+ dogs was identified between dogs that received adjuvant chemotherapy (n = 4; 110 days) and those that did not receive adjuvant chemotherapy (n = 6; 125 days) (p = 0.4409). There was no difference in survival time in LN- dogs receiving chemotherapy (n = 12; 335 days) as compared to those LN- dogs (n = 10) that did not receive adjuvant chemotherapy (258.5 days; p = 0.6475). Conclusions and Clinical Relevance: The survival of primary pulmonary neoplasia in dogs with intrathoracic nodal metastasis is longer than previously reported in this contemporary cohort. Chemotherapy did not appear to improve survival in LN+ or LN- dogs. The combination of tumor size between 100 and 999 cm3 and positive lymph node status significantly reduced survival.

The development of an indirect computed tomography lymphography protocol for sentinel lymph node detection in head and neck cancer and comparison to other sentinel lymph node mapping techniques.

Identification of metastatic disease critically impacts the care and prognosis of patients with neoplasia. Multiple techniques exist for identifying the sentinel or first lymph node(s) that receive draining tumour lymph. Identification of the sentinel lymph node enables accurate tissue sampling for determination of lymphatic metastasis. The aims of this study were to develop a computed tomography (CT) protocol for identifying the sentinel lymph node in dogs with tumours of the head and neck. In addition, indirect CT lymphography was compared to lymphoscintigraphy and vital dye injection to determine which technique more reliably identified the sentinel lymph node. CT indirect lymphography using intratumoral injection of iodinated contrast identified draining lymphatic vessels in eight of 18 dogs and identified the sentinel lymph node in five of 18 dogs. CT indirect lymphography employing four-quadrant peritumoral injection of iodinated contrast identified draining lymphatic vessels in 18 of 20 dogs and identified the sentinel lymph node in 11 of 20 dogs. Vital dye injection and lymphoscintigraphy identified the sentinel lymph node in 17 of 18 and 20 of 20 dogs, respectively. Identified sentinel lymph nodes were either ipsilateral or bilateral to the primary tumour. Both CT techniques were found to be safe and simple. Peritumoral injection has the greatest promise for the detection of sentinel lymph nodes in various head and neck cancers using CT, while lymphoscintigraphy had the greatest success of the compared techniques.

Analysis of outcome in dogs that undergo secondary amputation as an end-point for managing complications related to limb salvage surgery for treatment of appendicular osteosarcoma.

Appendicular osteosarcoma (OSA) remains a prevalent musculoskeletal cancer in dogs and definitive local control followed by adjuvant cytotoxic chemotherapy is considered the gold standard approach. Several studies support surgical limb salvage as a means of local control with similar outcomes compared with limb amputation. Complications are well described for limb salvage but little is known of dogs that undergo secondary amputation as a result of complications and outcomes specific to this group. A retrospective analysis of dogs in an institutional primary bone tumour registry was performed to identify dogs diagnosed with histologically confirmed OSA treated with surgical limb salvage with a technique that required an implant to reconstruct the osseous defect. A total of 192 dogs were identified with 31 dogs undergoing secondary amputation representing a limb preservation rate of 84%. A total of 111 dogs were analysed: 31 secondary amputation cases and 80 controls were selected for comparison. The most common reasons for secondary amputation were local recurrence (LR) and surgical site infection (SSI), with odds ratios of 3.6 and 1.7, respectively. Dogs that underwent secondary amputation had a significantly (P = .05) longer median disease specific survival time (ST) (604 days) compared with the control group (385 days). Dogs lived for a median of 205 days beyond secondary amputation and 97% had good functional outcome. Significant independent factors that positively influenced ST were secondary amputation, moderate SSI, severe SSI and age.

Clinical outcome of congenital extrahepatic portosystemic shunt attenuation in dogs aged five years and older: 17 cases (1992-2005).

OBJECTIVE: To assess the outcome of extrahepatic portosystemic shunt (EHPSS) treatment in dogs aged 5 years and older. DESIGN: Retrospective case series. ANIMALS: 17 client-owned dogs. PROCEDURES: Medical records for dogs (> or = 5 years old) that underwent surgical attenuation of an EHPSS (1992 through 2005) were evaluated; data, including clinical signs, clinicopathologic findings, surgical procedure, and outcome, were recorded. Follow-up information was obtained via patient examination or telephone interview with veterinarians and owners. RESULTS: Dogs (5 to 9 years old [median age, 6.6 years]) had neurologic (n = 12), urinary tract (8), and gastrointestinal tract (6) EHPSS-associated clinical signs. Serum bile acids and ammonia concentrations were abnormal in all evaluated dogs. Treatment of EHPSSs included complete (n = 6 dogs) or partial (2) suture attenuation or ameroid constrictor placement (9). Two dogs died following surgery. Follow-up information (6 to 120 months) was available for 13 dogs. Deaths were attributable to heart failure (n = 1), bacterial hepatitis (2; with pyelonephritis in 1 dog), and unknown causes (3). At a median of 23 and 25 months, serum bile acids concentrations had almost normalized in 5 of 8 dogs and ammonia concentrations were within reference limits in 3 of 5 dogs, respectively; dogs with abnormal liver function test results had no associated clinical signs. Median long-term survival time was 72 months. CONCLUSIONS AND CLINICAL RELEVANCE: Attenuation of EHPSS in > or = 5-year-old dogs ameliorated signs of liver dysfunction in surviving dogs, although return of normal liver function occurred less frequently than expected.

Postamputation Orthopedic Surgery in Canine Amputees: Owner Satisfaction and Outcome.

Surgical management of postamputation orthopedic disease (PAOD) in canine amputees has rarely been documented, and no reports describing outcome of stifle surgery in canine amputees are available. The objective of this multisite retrospective case series was to describe cases and evaluate satisfaction with and outcome of postamputation orthopedic surgery in canine amputees. Data was obtained through medical records and owner survey responses; data included signalment, amputation cause, diagnosis, surgical treatment, timeframes, and outcome assessment. Outcome was categorized as acceptable or unacceptable, and complications were classified as catastrophic, major, or minor. Eleven thoracic limb amputees and 6 pelvic limb amputees with surgically treated PAOD were identified. Surgically treated PAOD was reported at a median of 9.7 months (range 0.5-110 months) after amputation. All 17 amputees were treated for pelvic limb disease, predominantly for cranial cruciate ligament disease that occurred in 11 of 17 dogs. Major complications following orthopedic surgeries performed in 3 thoracic limb amputees consisted of infection (n = 2) and uncontrolled pain (n = 1). No major complications were reported following orthopedic surgeries performed in pelvic limb amputees. Acceptable mid-to-long-term outcome was achieved in 16 of the 17 canine amputees. Surgical treatment of pelvic limb disease did not appear to be associated with a high number of major complications in this case series. These findings suggest that orthopedic surgery, specifically stifle surgery, in canine amputees might be considered a feasible treatment option. Although there are inherent methodological limitations of retrospective studies and owner surveys, our case series provides new information that might help guide surgical treatment decisions in canine amputees suffering from orthopedic disease. Prospective studies using objective outcome measures evaluating surgical management of PAOD are necessary to confirm the provided information.

Intraoperative and postoperative complications of partial maxillectomy for the treatment of oral tumors in dogs.

OBJECTIVE To characterize and identify factors associated with intraoperative and postoperative complications of maxillectomy in dogs with oral tumors. DESIGN Retrospective cohort study. ANIMALS 193 dogs that underwent maxillectomy for oral tumor excision from 2000 through 2011. PROCEDURES Data were extracted from the medical records regarding dog signalment, tumor location and size, histologic findings, clinical stage, maxillectomy category, surgical approach, and additional treatments provided. These factors were examined for associations with recorded intraoperative and postoperative outcomes. RESULTS The most common intraoperative complication was excessive surgical bleeding (103/193 [53.4%]), for which 44 (42.7%) dogs received an intraoperative blood transfusion. These outcomes were both significantly associated with tumor size and location, maxillectomy type, and surgical approach. Dogs treated with a dorsolateral combined intraoral surgical approach were more likely to have excessive surgical bleeding (48/58 [83%]) and had a longer mean duration of surgery (106 minutes) than those treated with an intraoral approach (29/54 [54%] and 77 minutes, respectively). Complications developing within 48 hours after surgery included epistaxis (99/193 [51.3%]), excessive facial swelling (71/193 [36.8%]), facial pawing (21/193 [10.9%]), and difficulty eating (22/193 [11.4%]). Complications developing within 48 hours to 4 weeks after surgery included lip trauma (22/164 [13.4%]), oronasal fistula formation (18/164 [11.0%]), wound dehiscence (18/164 [11.0%]), and infection (13/164 [7.9%]). CONCLUSIONS AND CLINICAL RELEVANCE Complications associated with maxillectomy in dogs were generally minor. Aggressive surgical planning, preparedness for hemorrhage and transfusion, careful tissue dissection, and comprehensive pain control are recommended, particularly for dogs with large, caudally located oral tumors requiring extensive excision.

Dedifferentiated Chondrosarcoma in the Dog and Cat: A Case Series and Review of the Literature.

This retrospective case series describes seven dogs and one cat diagnosed with dedifferentiated chondrosarcoma, an uncommon, aggressive variant of chondrosarcoma. The purpose of the study is to describe clinical, imaging, and histopathological findings of this tumor. Medical records and the diagnostic laboratory database at Colorado State University from 2000 to 2015 were reviewed and complete medical records were available for the eight animals in this report. Similar to what has been reported in people, poor long-term survival and high metastatic rate, particularly to the lungs, was observed in our case series. A bimorphic pattern on imaging (radiographs, computed tomography, and MRI) consisting of mineralized and nonmineralized areas was seen mirroring the high-grade sarcomatous component adjacent to a low-grade chondroid component seen histopathologically. A review of the human literature including suspected etiology, imaging findings, histopathology, and survival times with various treatment options is presented. This article describes the first reported cases of dedifferentiated chondrosarcoma in the veterinary literature. Early accurate recognition could lead to treatment plans tailored to this variant.

Prognosis for dogs with stage III osteosarcoma following treatment with amputation and chemotherapy with and without metastasectomy.

OBJECTIVE To determine survival times of selected dogs with metastatic (stage III) osteosarcoma, whether disease-free interval (DFI) was associated with survival time after diagnosis of stage III disease (ie, stage III survival time), and whether a survival benefit of metastasectomy existed. DESIGN Retrospective case series with nested cohort study. ANIMALS 194 client-owned dogs treated for histologically confirmed appendicular osteosarcoma from 1997 through 2009. PROCEDURES Dogs were included if they had stage I or II osteosarcoma at the time of initial evaluation, had amputation of the affected appendage and ≥ 1 dose of chemotherapy afterward, and developed metastasis within the follow-up period or prior to death. Data collected from the medical records included signalment, primary tumor location, clinical and laboratory findings, whether metastasectomy was performed, and outcome. Various factors were examined for associations with outcome. RESULTS Dogs that received no treatment for the metastasis had a median survival time between 49 and 57 days after diagnosis of stage III osteosarcoma. Duration of the preceding DFI had no association with this period. Metastasectomy alone was associated with a longer median stage III survival time (232 days) than no metastasectomy (49 days). Among all dogs identified as qualifying for pulmonary metastasectomy on the basis of < 3 pulmonary nodules visible on thoracic radiographs and a DFI > 275 days (n = 21), a survival advantage was also identified for those that actually received pulmonary metastasectomy (6). CONCLUSIONS AND CLINICAL RELEVANCE Preceding DFI had no influence on survival time of dogs with stage III osteosarcoma. Metastasectomy was associated with an increase in survival time for selected dogs.

Nose and Nasal Planum Neoplasia, Reconstruction.

Most intranasal lesions are best treated with radiation therapy. Computed tomographic imaging with intravenous contrast is critical for treatment planning. Computed tomographic images of the nose will best assess the integrity of the cribriform plate for central nervous system invasion by a nasal tumor. Because of an owner's emotional response to an altered appearance of their dog's face, discussions need to include the entire family before proceeding with nasal planectomy or radical planectomy. With careful case selection, nasal planectomy and radical planectomy surgeries can be locally curative.

Docetaxel Accumulates in Lymphatic Circulation Following Subcutaneous Delivery Compared to Intravenous Delivery in Rats.

BACKGROUND: The circulatory pathway for particles deposited outside of blood capillaries has not been well characterized for non-traditionally-delivered chemotherapeutics. MATERIALS AND METHODS: Blood and lymph pharmacokinetics of docetaxel (5 mg/kg) and carboplatin (14 and 28 mg/kg) following subcutaneous (s.c.) versus intravenous (i.v.) delivery were determined in a rodent model with catheterizations of both the thoracic lymphatic duct and jugular vein for prolonged synchronous blood and lymph sampling. RESULTS: Subcutaneous docetaxel demonstrates preferential lymphatic accumulation based on the area under the time-concentration curve (AUC0-24h) whereas i.v. docetaxel resulted in a greater plasma maximum concentration measured (Cmax). The apparent elimination half-life (t1/2) in lymph for docetaxel is greater following i.v. or s.c. delivery compared to t1/2 in blood. Carboplatin demonstrates a dose-dependent increase in plasma Cmax regardless of delivery route; the total carboplatin exposure over 24 h in lymph and plasma are comparable. CONCLUSION: Subcutaneous docetaxel achieves lymphatic accumulation greater than that of i.v. delivery.

Surgical management of gallbladder mucoceles in dogs: 22 cases (1999-2003).

OBJECTIVES: To describe preoperative, surgical, and postoperative findings and determine prognostic indicators and treatment recommendations in dogs treated surgically for gallbladder mucocele. DESIGN: Retrospective study. ANIMALS: 22 client-owned dogs. PROCEDURES: Medical records of dogs with gallbladder mucoceles that were treated surgically were reviewed. History, clinical signs, results of selected clinicopathologic analyses and abdominal ultrasonography, surgical procedure performed, results of histologic examination of a liver biopsy specimen, and survival time were recorded. Follow-up information was obtained via telephone interview with owners and referring veterinarians. RESULTS: Dogs were 7 to 15 years of age and had non-specific clinical signs (vomiting, anorexia, and lethargy). Physical examination findings included icterus, signs of depression, and signs of discomfort on palpation of the abdomen. Sixteen dogs had a definitive diagnosis and 6 dogs were strongly suspected of having a gallbladder mucocele on the basis of results of abdominal ultrasonography. Fifteen dogs survived after surgery; 3 of these dogs had bile-induced peritonitis, and 4 had pancreatitis. One dog was euthanatized as a result of severe pancreatitis, and 1 was euthanatized because of acute renal failure; 5 dogs died as a result of pancreatitis, cholecystitis, or bile-induced peritonitis. Hepatic abnormalities were detected histologically in all dogs. CONCLUSIONS AND CLINICAL RELEVANCE: No predictors of survival were identified. No associations between outcome of surgical treatment (survival vs nonsurvival) and preoperative findings, biliary rupture, surgical procedure performed, results of histologic examination of the liver, or development of pancreatitis were found. Cholecystoduodenostomy and cholecystectomy appear to be acceptable treatments for gallbladder mucocele.