To describe a modified approach to closed anal sacculectomy and report the short-term outcomes of dogs that underwent the procedure for treatment of neoplasia.
16 client-owned dogs.
Medical records of 1 referral hospital were reviewed to identify dogs that underwent modified closed anal sacculectomy for treatment of anal sac neoplasia between January 2018 and September 2020. Data collected included signalment, examination and diagnostic imaging findings, surgical details, intraoperative and postoperative complications, cytologic and histologic findings, adjuvant treatments, duration of follow-up, and short-term outcome.
15 dogs had apocrine gland anal sac adenocarcinoma, and 1 had a collision tumor. No dogs had intraoperative complications; 1 dog had a minor postoperative complication (paraparesis) that resolved. The median duration of postoperative follow-up was 286 days (range, 67 to 777 days). One dog had confirmed local disease recurrence 290 days after surgery, and 1 had suspected local disease recurrence 203 days after surgery and was euthanized because of systemic disease progression.
CONCLUSIONS AND CLINICAL RELEVANCE
The modified closed anal sacculectomy was well tolerated in this sample of dogs, with minimal short-term complications. This study provided evidence to justify evaluation of the procedure in a larger number of dogs and assessment of the effects of procedural modifications on postoperative complication rates and time to local recurrence.
OBJECTIVE To evaluate effects of anatomic location, histologic processing, and sample size on shrinkage of excised canine skin samples.
SAMPLE Skin samples from 15 canine cadavers.
PROCEDURES Elliptical samples of the skin, underlying subcutaneous fat, and muscle fascia were collected from the head, hind limb, and lumbar region of each cadaver. Two samples (10 mm and 30 mm) were collected at each anatomic location of each cadaver (one from the left side and the other from the right side). Measurements of length, width, depth, and surface area were collected prior to excision (P1) and after fixation in neutral-buffered 10% formalin for 24 to 48 hours (P2). Length and width were also measured after histologic processing (P3).
RESULTS Length and width decreased significantly at all anatomic locations and for both sample sizes at each processing stage. Hind limb samples had the greatest decrease in length, compared with results for samples obtained from other locations, across all processing stages for both sample sizes. The 30-mm samples had a greater percentage change in length and width between P1 and P2 than did the 10-mm samples. Histologic processing (P2 to P3) had a greater effect on the percentage shrinkage of 10-mm samples. For all locations and both sample sizes, percentage change between P1 and P3 ranged from 24.0% to 37.7% for length and 18.0% to 22.8% for width.
CONCLUSIONS AND CLINICAL RELEVANCE Histologic processing, anatomic location, and sample size affected the degree of shrinkage of a canine skin sample from excision to histologic assessment.
OBJECTIVE To compare clinical signs, laboratory test results, and imaging findings between dogs with suspected anaphylaxis and dogs with sepsis.
DESIGN Retrospective case-case study.
ANIMALS 10 dogs with suspected anaphylaxis and 22 dogs with confirmed sepsis that met the criteria for systemic inflammatory response syndrome.
PROCEDURES Medical records for dogs in each group were reviewed and data extracted regarding signalment; reason for hospital admission; physical examination findings; results of CBC, serum biochemical analysis, coagulation testing, cytologic examination, and microbial culture; and imaging reports.
RESULTS All dogs in the anaphylaxis group fulfilled the criteria for systemic inflammatory response syndrome. Dogs in both groups had gastrointestinal signs, lethargy, mentation change, and bleeding abnormalities. Dogs with suspected anaphylaxis had a significantly higher eosinophil count and serum alanine aminotransferase activity and lower blood pH than dogs with sepsis. Dogs with sepsis had a significantly higher band neutrophil count, serum globulins concentration, and serum alkaline phosphatase activity and lower serum glucose concentration. Dogs in both groups had intracavitary free fluid and ultrasonographic findings of thickened intestines, gas or fluid-filled intestines, and a thickened gallbladder wall.
CONCLUSIONS AND CLINICAL RELEVANCE Clinical signs, laboratory values, and imaging findings may be similar in dogs with sepsis or anaphylaxis. Given the marked difference in prognosis and treatment, early differentiation is important. Anaphylaxis should be considered if a septic nidus cannot be identified, and supportive care should be considered for such patients.
Objective—To identify risk factors for urolithiasis in dogs with congenital extrahepatic portosystemic shunts (EHPSSs) and to determine whether portoazygos shunts were associated with increased risk of urolithiasis at the initial evaluation for EHPSS.
Design—Retrospective case series.
Animals—Dogs (n = 95) with EHPSSs confirmed via CT angiography or surgery.
Procedures—Medical records from 1999 to 2013 were reviewed. Variables of interest included signalment, previous medical management, and results of urinalysis, urolith analyses, and diagnostic imaging. Univariable and multivariable logistic regression analyses for assessment of risk factors for urolithiasis at the time of initial EHPSS evaluation were performed.
Results—The dogs’ median age was 0.9 years (range, 0.2 to 12.6 years). Among the 95 dogs, 27 (28.4%) and 68 (71.6%) had portoazygos and portocaval shunts, respectively. Urinalysis was performed for 79 (83.2%) dogs, 29 (36.7%) of which had crystalluria (mainly ammonium urate and struvite crystals). Uroliths were present in 34 of 95 (35.8%) dogs; 16 of 17 uroliths analyzed were composed of ammonium urate. Portoazygos shunts were not associated with significantly increased odds of urolithiasis at the time of the initial evaluation for EHPSS. However, the odds of urolithiasis was significantly increased for male dogs, older dogs, and dogs that received previous medical treatment.
Conclusions and Clinical Relevance—In dogs with EHPSS, shunt morphology was not associated with increased odds of urolithiasis at the initial evaluation. Male dogs, older dogs, and dogs having received medical management for EHPSS prior to initial evaluation should be considered at increased risk for development of urolithiasis.
OBJECTIVE To assess for any association between a history of tibial plateau leveling osteotomy (TPLO) and subsequent development of proximal tibial osteosarcoma in dogs.
DESIGN Matched case-control study.
ANIMALS 34 client-owned dogs in which proximal tibial osteosarcoma was diagnosed between January 2005 and December 2012 (cases) and 79 dogs without osteosarcoma, matched 3:1 to cases (when possible) by age, breed, and initial examination date (controls).
PROCEDURES Information on each case and control was collected from the medical records and other sources regarding date of birth, sex and neuter status, body weight, breed, and whether TPLO had been performed ≥ 1 year ago. A multivariable conditional logistic regression model was constructed to evaluate associations of body weight and history of TPLO with the outcome of proximal tibial osteosarcoma in dogs.
RESULTS After adjusting for body weight in the multivariable model, dogs with a history of TPLO were 40 times as likely to develop proximal tibial osteosarcoma as were dogs with no history of TPLO. In addition, each 1-kg (2.2-lb) increase in body weight was associated with an 11% increase in the odds of proximal tibial osteosarcoma.
CONCLUSIONS AND CLINICAL RELEVANCE Results suggested that dogs with a history of TPLO were at increased risk of developing osteosarcoma of the proximal region of the tibia relative to dogs with no such history. Therefore, it is important for proximal tibial osteosarcoma to be included among the differential diagnoses for new or worsening hind limb lameness in dogs that underwent TPLO ≥ 1 year previously.
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.
Objective—To evaluate the outcome in terms of progression-free interval (PFI) and overall survival time (ST) after curative-intent resection of oral melanoma in dogs.
Design—Retrospective case series.
Animals—70 client-owned dogs.
Procedures—An electronic medical record search and review was performed for dogs that underwent curative-intent resection of oral melanoma (May 1, 1998, to December 31, 2011). Information gathered included signalment, oral location of tumor, staging results, type of surgery, type of adjuvant therapy, findings on histologic evaluation, and outcome.
Results—36 (51.4%), 16 (22.9%), 13 (18.6%), and 1 (1.4%) of 70 dogs had tumors classified as stage I, II, III, and IV, respectively; tumor stage could not be determined for 4 (5.7%) dogs because of the lack of tumor size information. Fifty-one (72.9%) dogs had tumors completely excised. Twenty-nine (41.4%) dogs received adjuvant therapy. Median PFI and ST were 508 and 723 days, respectively. Thirty-two (45.7%) dogs had disease progression. Significant associations with PFI or ST were found for administration of adjuvant therapy, presence of metastatic disease at the time of diagnosis, higher tumor stage (III or IV), increased tumor size (> 3 cm), and sexually intact female dogs. Administration of adjuvant treatment was associated with a 130% increased hazard (hazard ratio, 2.3; 95% confidence interval [CI], 1.0 to 5.0) of disease progression; the presence of metastases at the time of diagnosis was associated with a 281% increased hazard (hazard ratio, 3.8; 95% CI, 1.5 to 9.6) of death.
Conclusions and Clinical Relevance—Results indicated that dogs with oral melanoma can have a long PFI and ST after resection with wide margins.
Objective—To describe outcomes for small-breed dogs with appendicular osteosarcoma.
Design—Multi-institutional retrospective case series.
Animals—51 small-breed dogs.
Procedures—Records from participating Veterinary Society of Surgical Oncology members were searched for dogs that weighed ≤ 15 kg (33 lb) with a histologic diagnosis of appendicular osteosarcoma. The Kaplan-Meier method was used to determine median survival times (MSTs), and Cox regression was performed to identify variables associated with survival time.
Results—Tumors were most commonly located on the humerus (n = 15) and femur (14). Of the 51 study dogs, 9 were treated nonsurgically, 16 underwent amputation of the affected limb only, and 26 underwent curative-intent treatment, with MSTs of 112, 257, and 415 days, respectively. The MST did not differ significantly between dogs in the amputation-only and curative-intent groups. For dogs in the nonsurgical group, MST decreased significantly as the tumor histologic score increased. For dogs in the amputation-only group, MST decreased as body weight increased.
Conclusions and Clinical Relevance—For the small-breed dogs with appendicular osteosarcoma of the present study, tumor histologic grade and mitotic index were subjectively lower and MST following amputation of the affected limb without adjuvant chemotherapy was longer, compared with those for similarly affected larger dogs. Results indicated no significant advantage in MST for dogs that underwent curative-intent treatment versus dogs that underwent amputation only, and further investigation of the importance of adjuvant chemotherapy is warranted.
Objective—To describe the biological behavior, clinical outcome, and prognostic factors of osteosarcoma of the maxilla, mandible, or calvarium in dogs.
Design—Retrospective case series.
Animals—183 client-owned dogs with osteosarcoma of the maxilla, mandible, or calvarium.
Procedures—Medical records for dogs treated for osteosarcoma of the maxilla, mandible, or calvarium from 1986 through 2012 were reviewed. Dogs with a histopathologic diagnosis of osteosarcoma and treated for a primary tumor arising from these bones of the head were included.
Results—Mean age was 9.3 years, and body weight was 31.8 kg (70.0 lb). Most dogs (124/183 [67.8%]) were purebred, and the most common primary tumor site was the maxilla (80 [43.7%]). Treatments included palliative medical treatment only (11/183 [6.0%]), coarsely fractionated radiation therapy (RT; 12 [6.6%]), fractionated or stereotactic RT (18 [9.8%]), surgery (135 [73.8%]), and both surgery and fractionated RT (7 [3.8%]). Eighty-three (45.4%) dogs received adjuvant chemotherapy. Local recurrence or progression occurred in 80 of 156 (51.3%) dogs, and 60 of 156 (38.5%) dogs developed distant metastases. Median survival time for all dogs was 239 days. Dogs that underwent surgery had a median survival time of 329 days. Histologically tumor-free surgical margins were associated with significantly decreased hazards of progression or recurrence (hazard ratio [HR], 0.4) and death (HR, 0.5). Dogs with osteosarcoma of the calvarium had a significantly greater hazard of local recurrence or progression (HR, 2.0).
Conclusions and Clinical Relevance—In this study, tumor excision in dogs with histologically tumor-free margins resulted in better local control and longer survival time than did other treatment types.
Objective—To determine the signalment, tibial plateau leveling osteotomy (TPLO) plate type, clinical staging information, treatment, and oncological outcome in dogs that developed osteosarcoma at the proximal aspect of the tibia following TPLO and to calculate the interval between TPLO and osteosarcoma diagnosis.
Design—Multi-institutional retrospective case series.
Procedures—Medical records from 8 participating institutions were searched for dogs that developed osteosarcoma (confirmed through cytologic or histologic evaluation) at previous TPLO sites. Signalment, TPLO details, staging tests, treatment data, and outcome information were recorded. Descriptive statistics were calculated, and disease-free intervals and survival times were evaluated by means of Kaplan-Meier analysis.
Results—29 dogs met the inclusion criteria. The mean age was 9.2 years and mean weight was 45.1 kg (99.2 lb) at the time of osteosarcoma diagnosis. Most dogs had swelling over the proximal aspect of the tibia (17/21) and lameness of the affected limb (28/29). The mean interval between TPLO and osteosarcoma diagnosis was 5.3 years. One type of cast stainless steel TPLO plate was used in most (18) dogs; the remaining dogs had received plates of wrought stainless steel (n = 4) or unrecorded type (7). Twenty-three of 29 dogs underwent treatment for osteosarcoma. Median survival time for 10 dogs that underwent amputation of the affected limb and received ≥ 1 chemotherapeutic treatment was 313 days.
Conclusions and Clinical Relevance—Results supported that osteosarcoma should be a differential diagnosis for dogs with a history of TPLO that later develop lameness and swelling at the previous surgical site. Oncological outcome following amputation and chemotherapy appeared to be similar to outcomes previously reported for dogs with appendicular osteosarcoma.