S creening diagnostics are used to detect metastasis as well as other diseases that may affect the prognosis or treatment plan. In veterinary medicine, there are no published consensus guidelines for screening oral tumors, 1 , 2 such as those
controls reacted appropriately.
Morphologic Diagnosis and Case Summary
Thymoma (type B3) with hepatic, pulmonary, and vertebral metastasis.
Differential diagnoses for a cranial mediastinal mass include thymoma, lymphoma
, right-to-left lateral thoracic radiography was performed. No pulmonary metastasis was seen, but expansile osteolytic lesions were observed in the extremities of the spinous processes of T2, T6, and T7 ( Figures 1 and 2 ) .
mediastinal mass ( Figure 2 ). The mass was located caudal to the internal thoracic arteries and ventral to the cranial vena cava; however, these structures did not appear to be invaded by the mass. No evidence of pulmonary metastasis was detected.
–4 Although minimally invasive surgery has few reported complications and is associated with better postoperative patient comfort, potential complications exist. In humans, metastasis of neoplasia to the abdominal wall or subcutis at the site of portal
with STS, 3 , 4 , 5 and CT is more sensitive than radiography in detecting pulmonary metastases in dogs with neoplasia. 21 , 22 , 23 Information on the prevalence of STS pulmonary metastasis at presentation is sparse. For instance, Bray et al 15
grading system was demonstrated to be more accurate at predicting metastasis development and death than the Patnaik system. 5
The purpose of the study reported here was to retrospectively analyze a large series of cases to compare the 2-category Kiupel
Objective—To determine the association between
lymph node size and metastasis and to assess measurement
of lymph node size as an accurate and reliable
means of tumor staging in dogs with oral malignant
Animals—100 dogs with histologically confirmed oral
Procedure—Clinical records for dogs with oral malignant
melanoma were reviewed. Data regarding size
and results of cytologic or histologic examination of
lymph nodes were evaluated. The association
between lymph node size and metastasis was determined.
Results—Forty-seven (47%) dogs, of which 23 (49%)
had enlarged mandibular lymph nodes, had no cytologic
or histologic evidence of metastasis. Of 53
(53%) dogs with cytologic or histologic evidence of
mandibular lymph node metastasis, 37 (70%) had
enlarged mandibular lymph nodes, and 16 (30%) had
mandibular lymph nodes of normal size. Overall, 16 of
the 40 (40%) dogs with normal-sized lymph nodes
had microscopic evidence of metastatic disease.
Sensitivity and specificity of lymph node size as a predictor
of metastasis were 70 and 51%, respectively,
and the positive and negative predictive values were
62 and 60%, respectively.
Conclusions and Clinical Relevance—Although a
significant relationship was identified between lymph
node size and metastasis to the lymph node, this
association did not appear strong enough to be clinically
relevant. Results suggest that lymph node size
alone is insufficient for accurate clinical staging of oral
malignant melanoma in dogs; cytologic or histologic
examination of regional lymph nodes should routinely
be performed, regardless of size of those nodes. (J
Am Vet Med Assoc 2003;222:1234–1236)
Objective—To determine whether thalidomide
inhibits the growth of primary and pulmonary
metastatic canine osteosarcoma in mice after xenotransplantation.
Animals—Athymic nude mice.
Procedure—Canine osteosarcoma cells were injected
SC in 50 mice. Mice were randomly placed into
the following groups: control group (n = 13; DMSO
[drug vehicle] alone [0.1 mL/d, IP]); low-dose group
(12; thalidomide [100 mg/kg, IP]), mid-dose group (13;
thalidomide [200 mg/kg, IP]); and high-dose group
(12; thalidomide [400 mg/kg, IP]). Starting on day 8,
treatments were administered daily and tumor measurements
were performed for 20 days. On day 28,
mice were euthanatized and primary tumors were
weighed. Lungs were examined histologically to
determine the number of mice with metastasis and
tumor emboli. Mean area of the pulmonary
micrometastatic foci was determined for mice from
Results—Primary tumor size and weight were not
significantly different among groups. The number of
mice in the mid-dose (200 mg/kg) and high-dose (400
mg/kg) groups with micrometastasis was significantly
less than the number of control group mice; however,
the number of mice with tumor emboli was not
affected by thalidomide treatment. Size of
micrometastasis lesions was not affected by thalidomide
Conclusions and Clinical Relevance—Mean area of
micrometastases was not affected by treatment;
however, growth of micrometastases had not yet
reached an angiogenesis-dependent size. Although
thalidomide did not affect growth of primary tumors in
mice after xenotransplantation of canine osteosarcoma
cells, our findings indicate that thalidomide may
interfere with the ability of embolic tumor cells to
complete the metastatic process within the lungs.
( Am J Vet Res 2004;65:659–664)
Procedure—1 × 107 POS osteosarcoma cells were
transplanted subcutaneously into the intrascapular
region of mice. All-trans RA (3 or 30 µg/kg of body
weight in 0.1 ml of sesame oil), 9-cis RA (3 or 30 mg/kg
in 0.1 ml of sesame oil), or sesame oil (0.1 ml; control
treatment) were administered intragastrically 5 d/wk
for 4 weeks beginning 3 days after transplantation (n =
4 mice/group) or after formation of a palpable tumor (5
mice/group). Tumor weight was estimated weekly by
measuring tumor length and width, and retinoid toxic
effects were evaluated daily. Two weeks after the final
treatment, mice were euthanatized, and number of
mice with pulmonary metastases was determined.
Results—Adverse treatment effects were not detected.
Tumor weight was less in mice treated with either
dose of 9-cis RA than in control mice, although this
difference was not significant. Treatment with 30 mg
of 9-cis RA/kg initiated after tumor formation significantly
reduced the incidence of pulmonary metastasis,
compared with the control group.
Conclusions and Clinical Relevance—9-cis RA
decreased the incidence of pulmonary metastasis in
nude mice transplanted with canine osteosarcoma
cells and may be a potential adjunct therapy for treatment
of osteosarcoma in dogs. (Am J Vet Res 2000;