CASE DESCRIPTION A 13-year-old Labrador Retriever with a 4-cm-diameter ulcerated perianal mass and a 12-year-old Golden Retriever with a 5-cm-diameter ulcerated caudolateral abdominal mass were brought to a referral oncology practice for evaluation of the dermal masses. Both masses were resected with wide margins without reported postoperative complications. For both dogs, a diagnosis of collision tumor was made. The database of the Veterinary Diagnostic Laboratories at Colorado State University was searched for other examples of collision tumors in dogs.
CLINICAL FINDINGS Histologic assessment of the masses revealed collision tumors in both patients. The perianal mass was diagnosed as a perianal gland carcinoma with adjacent hemangiosarcoma. The flank mass was diagnosed as a fibrosarcoma with an adjacent mast cell tumor. The university database search of sample submissions in 2008 through 2014 for the keywords collision, admixed, or adjacent yielded 37 additional cases of dogs with malignant nontesticular collision tumors.
TREATMENT AND OUTCOME Both dogs were treated with surgery alone and received no adjunctive treatments. Both tumors were completely excised. There was no evidence of either local tumor recurrence or metastasis in the Labrador Retriever and the Golden Retriever at 1,009 and 433 days after surgery, respectively.
CLINICAL RELEVANCE Collision tumors are rare, and there is minimal information regarding treatment recommendations and outcome for animals with collision tumors. On the basis of the 2 cases described in this report, the outcome associated with treatment of collision tumors may be similar to the expected outcome for treatment of any of the individual tumor types in dogs.
Objective—To determine whether results of histologic examination of hepatic biopsy samples could be used as an indicator of survival time in dogs that underwent surgical correction of a congenital portosystemic shunt (PSS).
Design—Retrospective case series.
Animals—64 dogs that underwent exploratory laparotomy for an extrahepatic (n = 39) or intrahepatic (25) congenital PSS.
Procedures—All H&E-stained histologic slides of hepatic biopsy samples obtained at the time of surgery were reviewed by a single individual, and severity of histologic abnormalities (ie, arteriolar hyperplasia, biliary hyperplasia, fibrosis, cell swelling, lipidosis, lymphoplasmacytic cholangiohepatitis, suppurative cholangiohepatitis, lipid granulomas, and dilated sinusoids) was graded. A Cox proportional hazards regression model was used to determine whether each histologic feature was associated with survival time.
Results—Median follow-up time was 35.7 months, and median survival time was 50.6 months. Thirty-eight dogs were alive at the time of final follow-up; 15 had died of causes associated with the PSS, including 4 that died immediately after surgery; 3 had died of unrelated causes; and 8 were lost to follow-up. None of the histologic features examined were significantly associated with survival time.
Conclusions and Clinical Relevance—Findings suggested that results of histologic examination of hepatic biopsy samples obtained at the time of surgery cannot be used to predict long-term outcome in dogs undergoing surgical correction of a PSS.
Objective—To identify matrix metalloproteinases
(MMP) 2 and 9 in canine tumor tissue and to compare
the amount of activity to that in unaffected stromal
Animals—30 dogs with spontaneously developing,
Procedure—Tumor and nearby stromal tissue (muscle)
were obtained at the time of surgery. Specimens were
homogenized, and supernatants were assayed, using
gelatin zymography. Human derived standards were
run concurrently. Densitometry was done to obtain a
semiquantitative arbitrary unit value for each specimen.
The amount of activity in tumor tissue was compared
with the amount in stromal tissue.
Results—Gelatinolytic bands were observed from
the analysis of all tumor tissues and in most stromal
tissues. These bands migrated in the same molecular
weight area as the human MMP 2 and 9 standards.
Gelatinolytic activity could be quenched by the addition
of 50 mM EDTA and 1 µg of synthetic tissue
inhibitor of metalloproteinase (TIMP) 2 per 100 ml.
There was significantly more gelatinolytic activity in
tumor tissue than in stromal tissue.
Conclusions and Clinical Relevance—MMP 2 and 9
are detectable in canine neoplastic tissue. matrix metalloproteinases
activity in tumor tissue is higher than in
unaffected stromal tissue, indicating that canine MMP
may be involved in the pathogenesis of tumor growth
and metastasis. (Am J Vet Res 2000;61:111–114)
Objective—To evaluate outcomes of radical excision of feline injection-site sarcomas (ISS) via assessment of local recurrence and metastasis rates, survival times, and complications associated with surgery.
Design—Retrospective case series.
Animals—91 cats with ISS.
Procedures—Medical records of cats that had radical excision of ISS without adjunctive treatment were reviewed. Information extracted included sex, type of surgical procedure, histologic tumor grade, tumor diameter, time from tumor detection to definitive surgery, complications associated with surgery, whether tumors recurred locally or metastasized, and survival times. Diagnosis of ISS was histologically confirmed, and additional follow-up was performed.
Results—Overall median survival time was 901 days. Thirteen of 91 (14%) cats had local tumor recurrence; 18 (20%) cats had evidence of metastasis after surgery. Median survival time of cats with and without recurrence was 499 and 1,461 days, respectively. Median survival time of cats with and without metastasis was 388 and 1,528 days, respectively. Tumor recurrence and metastasis were significantly associated with survival time, whereas other examined variables were not. Major complications occurred in 10 cats, including 7 with incisional dehiscence.
Conclusions and Clinical Relevance—Radical excision of ISS resulted in a metastasis rate similar to rates reported previously; the local recurrence rate appeared to be substantially less than rates reported after less aggressive surgeries, with or without adjuvant treatment. Major complication rates were similar to rates reported previously after aggressive surgical resection of ISS. Radical excision may be a valuable means of attaining an improved outcome in the treatment of feline ISS.
Objective—To determine the efficacy of primary re-excision alone for treatment of soft tissue sarcomas after recent incomplete resection, the frequency and clinical importance of detecting residual tumor in resected scars, and prognostic factors associated with the procedure.
Design—Retrospective case series.
Procedures—Medical records of dogs that had undergone recent incomplete excision of a soft tissue sarcoma at a referring veterinary practice and subsequent re-excision of the scar at the Colorado State University Veterinary Medical Center were reviewed.Owners and referring veterinarians were contacted for follow-up information.Slides from re-excised specimens were reviewed.Dogs that underwent radiation therapy after the re-excision procedure were excluded.
Results—41 dogs met the inclusion criteria, and long-term follow-up information was available for 39 dogs.Median follow-up time was 816 days.Local recurrence of tumor developed in 6 of 39 (15%) dogs, and distant metastasis occurred in 4 of 39 (10%) dogs.Healthy tis sue margins of 0.5 to 3.5 cm were achieved at re-excision. Residual tumor was identified in 9 of 41 (22%) resected scars.No tumor-, patient-, or treatment-related variables were associated with local recurrence except for the presence of liposarcoma or fibrosarcoma or whether fine-needle aspiration had been performed prior to surgery.
Conclusions and Clinical Relevance—After incomplete resection of soft tissue sarcomas, resection of local tissue should be performed, even if excisable tissue margins appear narrow.A long-term favorable prognosis is achievable without radiation therapy or amputation. The presence of residual tumor in resected scar tissue should not be used to predict local recurrence.
Case Description—5 Vietnamese potbellied pigs were evaluated for abdominal distress that had not responded to medical treatment (4 pigs) or a draining tract of the cranial abdomen of unknown duration (1 pig).
Clinical Findings—Clinical signs in the pigs included anorexia, vomiting, and constipation. Physical examination revealed a palpable abdominal mass in all pigs. Radiography revealed distended loops of small intestine in 2 pigs.
Treatment and Outcome—3 pigs were treated successfully with wide-margin excision of the abdominal masses, and 2 were euthanized. Primary tumors were diagnosed at necropsy or through histologic evaluation of biopsy specimens obtained during surgery. Types of tumor included cholangiocellular carcinoma, transmural gastric carcinoma, small intestinal adenocarcinoma, metastatic hepatocellular carcinoma, and carcinoma. The tumors involved the stomach, small intestine, spiral colon, liver, and gall bladder. All 3 surgically treated pigs survived at least 9 months after surgery.
Clinical Relevance—Although rare, neoplasia of the alimentary system should be considered among the differential diagnoses for potbellied pigs with signs of abdominal distress. Wide-margin excision of the neoplastic tissue may result in a good outcome in affected pigs.
Objective—To evaluate μ-opioid receptors in synovial
membranes of horses and determine whether these
receptors are up-regulated in nerve endings during
Sample Population—Synovial tissue obtained from
39 client-owned horses during arthroscopy and 14
research horses during necropsy; brain and synovial
tissues were obtained during necropsy from 1 horse,
and control tissues were obtained from a mouse.
Procedure—Horses were classified into 7 groups on
the basis of histologically determined degree of
inflammation. Binding of primary rabbit antibody
developed against μ-opioid receptors in equine synovial
tissue was studied, using western blot analysis.
Synovial membranes were tested for μ-opioid receptors
by immunohistochemical staining, using a
diaminobenzidine-cobalt chloride chromogen.
Homogenates of synovial membranes were evaluated
by use of radioligand binding.
Results—Examination of western blots of equine
thalamus revealed that rabbit antibody developed
against μ-opioid receptors yielded a band (molecular
weight, 55 kd) that corresponded with that of other
opioid receptors. Use of immunohistochemical staining
of synovial tissue revealed considerable staining
in the proliferative lining layer and in regions surrounding
vascular structures. Specific radioligand
binding of tissue homogenates was found in all
groups. We did not detect significant differences in
binding between horses with inflammation and horses
Conclusions and Clinical Relevance—Results of
immunohistochemical analysis and radioligand binding
of tissue homogenates suggest that there are opioid
receptors in synovial membranes of horses. Our
results support the practice of intra-articular administration
of opioids to relieve pain after arthroscopic
surgery in horses. (Am J Vet Res 2001;62:1408–1412).
Objective—To develop an orthotopic model of canine osteosarcoma in athymic rats as a model for evaluating the effects of stereotactic radiotherapy (SRT) on osteosarcoma cells.
Animals—26 athymic nude rats.
Procedures—3 experiments were performed. In the first 2 experiments, rats were injected with 1 × 106 Abrams canine osteosarcoma cells into the proximal aspect of the tibia (n = 12) or distal aspect of the femur (6). Tumor engraftment and progression were monitored weekly via radiography, luciferase imaging, and measurement of urine pyridinoline concentration for 5 weeks and histologic evaluation after euthanasia. In the third experiment, 8 rats underwent canine osteosarcoma cell injection into the distal aspect of the femur and SRT was administered to the affected area in three 12-Gy fractions delivered on consecutive days (total radiation dose, 36 Gy). Percentage tumor necrosis and urinary pyridinoline concentrations were used to assess local tumor control. The short-term effect of SRT on skin was also evaluated.
Results—Tumors developed in 10 of 12 tibial sites and all 14 femoral sites. Administration of SRT to rats with femoral osteosarcoma was feasible and successful. Mean tumor necrosis of 95% was achieved histologically, and minimal adverse skin effects were observed.
Conclusions and Clinical Relevance—The orthotopic model of canine osteosarcoma in rats developed in this study was suitable for evaluating the effects of local tumor control and can be used in future studies to evaluate optimization of SRT duration, dose, and fractionation schemes. The model could also allow evaluation of other treatments in combination with SRT, such as chemotherapy or bisphosphonate, radioprotectant, or parathyroid hormone treatment.
Objective—To determine clinical signs, diagnostic
findings, outcome, and prognostic factors in dogs
treated surgically for massive hepatocellular carcinoma
(HCC) and compare survival times of surgically
and conservatively treated dogs.
Procedure—Medical records were examined for clinical
signs, diagnostic and surgical findings, and postoperative
outcome. Dogs were allocated into surgery
and nonsurgery groups depending on whether curative-
intent liver lobectomy was performed. Data from
the surgical and nonsurgical groups were analyzed to
identify prognostic factors and determine and compare
rates of tumor control and survival time.
Results—42 dogs were treated surgically, and 6 were
managed conservatively. In the surgery group, intraoperative
mortality rate was 4.8% with no local recurrence,
metastatic rate was 4.8%, and median survival
time was > 1,460 days (range, 1 to 1,460 days). High
alanine aminotransferase and aspartate aminotransferase
activities were associated with poor prognosis.
Median survival time for the nonsurgery group was
270 days (range, 0 to 415 days), which was significantly
less than that of surgically treated dogs.
Conclusions and Clinical Relevance—Liver lobectomy
is recommended for dogs with massive HCC
because tumor-related mortality rate was 15.4 times
higher in dogs in the nonsurgery group, compared
with the surgery group. Tumor control was excellent
after surgical resection with no local recurrence and a
low metastatic rate. Prognostic factors were identified,
but their clinical relevance was uncertain
because only 9.5% of dogs in the surgery group died
as a result of their disease. (J Am Vet Med Assoc