D. Stefanello

The Spectrum of Canine Cutaneous Perivascular Wall Tumors: Morphologic, Phenotypic and Clinical Characterization

Perivascular wall tumors (PWTs) are defined as neoplasms deriving from mural cells of blood vessels, excluding the endothelial lining. The spectrum of human cutaneous PWT includes glomus tumor, hemangiopericytoma (HEP), myopericytoma, angioleiomyoma/sarcoma, angiomyofibroblastoma, and angiofibroma. The purpose of this study was to revise clinical presentation, cytology, histopathology, and immunohistology of canine cutaneous PWT with cytology typical of canine HEP. Diagnosis was established on the basis of vascular growth patterns (staghorn, placentoid, perivascular whorling, bundles from media) and immunohistology, including 7 smooth muscle markers and the cell membrane ganglioside of unknown origin recognized by the antibody 3G5 (CMG-3G5). Twenty cases were included. Ages ranged from 6 to 13 years; 12 dogs were males and 8 were females, and there was a prevalence of crossbreeds. Tumors arose from a single site with preferential acral location (10/20). Cytology revealed moderate to high cellularity in all cases, cohesive groups of cells (19/20), capillaries (18/20), and bi- to multinucleated cells (18/20). Six myopericytomas, 5 angioleiomyomas, 2 angioleiomyosarcomas, 2 HEP, 1 angiofibroma, and 1 adventitial tumor were identified. A definitive diagnosis was not possible in 3 cases. Smoothelin, heavy caldesmon, desmin, myosin, calponin, and CMG-3G5 were the most valuable markers to differentially diagnose canine PWT. Similar to reports in humans, canine HEP embodied a spectrum of neoplastic entities arising from different vascular mural cells. Before canine PWTs are assimilated into one prognostic category, a consistent classification and characterization of their biology is necessary. As proposed in humans, HEP should also be considered a diagnosis of exclusion in dogs.

Predictors of long-term survival in dogs with high-grade multicentric lymphoma

OBJECTIVE To determine factors predicting survival in dogs with high-grade multicentric lymphoma. Design-Retrospective cohort study. Animals-127 dogs with high-grade multicentric lymphoma evaluated at 4 veterinary hospitals from 2000 to 2009. PROCEDURES Records were reviewed to identify dogs with completely staged high-grade multicentric lymphoma treated with chemotherapy. Data collected included signalment, history, hematologic findings, tumor characteristics, treatment, and outcome. Long-term survival was defined as surviving > 2 years after diagnosis. Variables were analyzed for associations with dogs living > 2 years. RESULTS Among the 127 enrolled dogs, 13 (10%) survived > 2 years with a median survival time of 914 days (range, 740 to 2,058 days). Survival rates at 3, 4, and 5 years were 4%, 3%, and 1 %, respectively. At diagnosis, 11 of the 13 long-term survivors had a body weight ≥ 10 kg, PCV ≥ 35%, absence of ionized hypercalcemia, centroblastic lymphoma, immunophenotype B, absence of bone marrow involvement, and lymphoma stages I through IV and were not previously treated with corticosteroids. The same combination of factors was present in 26 of 114 (23%) dogs surviving ≤ 2 years, yielding a negative predictive value of 97.8% for long-term survivors. Four of the 6 long-term survivors that died during the study died of another cancer; 3 of them had osteosarcoma. CONCLUSIONS AND CLINICAL RELEVANCE Absence of the aforementioned combination of variables at diagnosis may help identify dogs with lymphoma that will not survive > 2 years. Other types of neoplasia, in particular osteosarcoma, may develop in long-term-surviving dogs.

Ultrasound-guided cytology of spleen and liver: a prognostic tool in canine cutaneous mast cell tumor.

BACKGROUND In the clinical staging of cutaneous mast cell tumors (cMCT), the diagnosis of metastasis is controversial based on cytological examination of lymph nodes, spleen, liver, bone marrow, and blood. OBJECTIVES To define the prognostic role of ultrasound-guided cytology of spleen and liver in cMCT. The results of cytological evaluation were compared in relation with survival time. ANIMALS Fifty-two client-owned dogs with a diagnosis of cMCT. METHODS Selection of cases was based on cytological evaluation of liver and spleen to detect infiltration at distant sites. The Kaplan Meier method was used to compare survival in dogs with and without infiltration of spleen and liver (log-rank test P < .05). RESULTS Ten dogs with cMCT had mast cell infiltration of spleen, liver, or both and 4 of these dogs had involvement of the regional lymph nodes. The majority of dogs had 2 or more ultrasonographically abnormal findings simultaneously in spleen and liver. Nine dogs had grade II cMCT, and 1 had grade III cMCT. Dogs with positive evidence of mast cell infiltration to spleen, liver, or both had shorter survival times (34 versus 733 days) compared with dogs negative for mast cell infiltration at distant sites. CONCLUSION AND CLINICAL IMPORTANCE Dogs with evidence of mast cell infiltration at distant sites have a shorter survival times than dogs without evidence of infiltration at distant sites. This study suggests that cytology of spleen and liver is indicated either for ultrasonographically normal or for ultrasonographically abnormal spleen and liver in dogs with cMCT.

Feline injection-site sarcoma: recurrence, tumour grading and surgical margin status evaluated using the three-dimensional histological technique.

The three-dimensional histology technique is used in human medicine for the evaluation of complete lateral and deep surgical margins. In this study, the technique was applied to 48 excised feline injection-site sarcoma specimens. The predictive value of the histological margin status and tumour grading on local recurrence was investigated. In 32/48 cases, the margins were non-infiltrated, whilst in the remaining 16 cases, they were infiltrated. Overall, 6/32 (19%) tumours with non-infiltrated margins and 11/16 (69%) with infiltrated margins recurred. Tumours with infiltrated margins recurred about 10 times more frequently compared to tumours with non-infiltrated margins (P=0.0011). No statistically significant correlation was observed between grading and recurrence. The assessment of margin status using the 3D histology technique showed a good predictivity for post-surgical tumour recurrence. Extensive application of the 3D histology technique is recommended to standardise the evaluation of histological margins and to allow comparison between results from different laboratories.

Prognostic factors for dogs with mammary inflammatory carcinoma: 43 cases (2003–2008)

OBJECTIVE To describe clinical characteristics, treatment, and outcome of dogs with inflammatory carcinoma (IC) and identify patient-, tumor-, and treatment-related factors associated with overall survival time. DESIGN Retrospective case series. ANIMALS 43 client-owned dogs. PROCEDURES Records of dogs with a clinical diagnosis of IC that had histologic evidence of dermal lymphatic invasion were reviewed. Data on clinical staging, treatment, toxicoses, response, and survival time were retrieved. Results-26 (60%) dogs had primary IC and 17 (40%) had secondary IC. Thirty-five (81%) dogs had distant metastases and 2 (5%) had local metastases at the time of initial examination. Six of 29 (21%) dogs had a coagulopathy. Sixteen (37%) dogs did not receive specific treatment for IC, 24 (56%) received medical treatment only, 2 (5%) underwent surgical excision and received medical treatment, and 1 (2%) underwent surgical excision only. Forty-one (95%) dogs had progressive disease, and 2 (5%) had stable disease. Mean survival time for all dogs was 60 days (range, 1 to 300 days). Dogs with a coagulopathy survived a significantly shorter time than did dogs without a coagulopathy (odds ratio, 0.28), and dogs that received medical treatment survived significantly longer than dogs that did not (odds ratio, 2.54). CONCLUSIONS AND CLINICAL RELEVANCE Results suggested that mammary IC is a biologically aggressive condition in dogs associated with a guarded prognosis. In addition, results suggested that medical treatment may improve outcome, thereby supporting its use in dogs with IC.

A Study of Mutations in the c-kit Gene of 32 Dogs with Mastocytoma

Mutations in the intracellular juxtamembrane domain of the c-kit gene in 32 dogs with different grades of histologically confirmed mastocytoma were studied. Transcript RNAs extracted from neoplastic tissue surgically collected from dogs of different breeds and from a negative control were reverse transcribed into complementary DNA and amplified by polymerase chain reaction. The region corresponding to the c-kit juxtamembrane domain was sequenced and compared with GenBank sequences. Two different types of mutations were identified within exon 11: a previously underscribed single-nucleotide substitution and a 6-bp deletion. The c-kit juxtamembrane domain sequences of all dogs were grouped in 3 clusters. No mutations were detected in tissues constitutively expressing c-kit (cerebellum and spleen), obtained from dogs not affected by mastocytoma (controls). All the substitutions were found in dogs bearing grade I or II mast cell tumors; the deletion was detected in 1 dog with grade II mastocytoma.

Immunophenotype predicts survival time in dogs with chronic lymphocytic leukemia.

BACKGROUND Chronic lymphocytic leukemia (CLL) is a hematologic disorder in dogs, but studies on prognostic factors and clinical outcome are lacking. In people, several prognostic factors have been identified and currently are used to manage patients and determine therapy. OBJECTIVES The aim of the study was to determine if the immunophenotype of neoplastic cells predicts survival in canine CLL. DESIGN Retrospective study. ANIMALS Forty-three dogs with CLL. PROCEDURES Records of dogs with a final diagnosis of CLL were reviewed. For each included dog, a CBC, blood smear for microscopic reevaluation, and immunophenotyping data had to be available. Data on signalment, history, clinical findings, therapy, follow-up, as well as date and cause of death were retrieved. RESULTS Seventeen dogs had B-CLL (CD21+), 19 had T-CLL (CD3+ CD8+), and 7 had atypical CLL (3 CD3- CD8+, 2 CD3+ CD4- CD8-, 1 CD3+ CD4+ CD8+, and 1 CD3+ CD21+). Among the variables considered, only immunophenotype was associated with survival. Dogs with T-CLL had approximately 3-fold and 19-fold higher probability of surviving than dogs with B-CLL and atypical CLL, respectively. Old dogs with B-CLL survived significantly longer than did young dogs, and anemic dogs with T-CLL survived a significantly shorter time than dogs without anemia. CONCLUSIONS Although preliminary, results suggested that immunophenotype is useful to predict survival in dogs with CLL. Young age and anemia are associated with shorter survival in dogs with B-CLL and T-CLL, respectively.

Cytosine arabinoside in addition to VCAA‐based protocols for the treatment of canine lymphoma with bone marrow involvement: does it make the difference?

Cytosine arabinoside (ara-C) is a component of many protocols for the treatment of acute leukaemia and non-Hodgkin lymphomas in humans. The aim of the study was to prospectively evaluate the efficacy of ara-C in a myeloablative regimen in a cohort of canine lymphomas with bone marrow involvement. Seventeen dogs were enrolled. Eight were treated with a VCAA-based protocol (Group 1) and nine with the same regimen added with ara-C (Group 2). Ara-C was administered on a 5-day schedule as an i.v. continuous infusion at the dose of 150 mg m(-2) per day for five consecutive days. During treatment complete remission (CR) was achieved in two dogs in Group 1 and in eight dogs in Group 2. CR rate was significantly higher in Group 2 (P < 0.01). Median survival was 72.5 days (range 6-174) in Group 1 and 243 days (range 73-635) in Group 2. Survival was significantly longer in Group 2 (P < 0.001). Both protocols were well tolerated, with a low incidence of adverse events. Ara-C added to a VCAA-based protocol appears to be safe and beneficial in dogs with stage V lymphoma. Incorporation of the nucleoside analogue might be crucial for the development of future therapeutic strategies in dogs.

VEGF and MMP-9: biomarkers for canine lymphoma.

Vascular endothelial growth factor (VEGF) and metalloproteinase (MMP) 2 and 9 are useful biomarkers in human lymphoma. During cancerogenesis, transforming growth factor beta (TGF-β) stimulates VEGF and MMPs production. VEGF and TGF-β plasma levels were tested by ELISA, MMP-2 and MMP-9 by gelatine zymography in 37 dogs with lymphoma, 13 of which were also monitored during chemotherapy. Ten healthy dogs served as control. Lymphoma dogs showed higher act-MMP-9 (P < 0.01) and VEGF (P < 0.05), and lower TGF-β than controls, and a positive correlation between act-MMP-9 and VEGF (P < 0.001). Act-MMP-9 and VEGF were significantly higher in T-cell lymphomas, and in stage V compared with stages III-IV disease, regardless of immunophenotype. VEGF was higher in high-grade compared with low-grade T-cell lymphomas. No correlation was found between cytokines levels at presentation and outcome. During chemotherapy, act-MMP-9 and VEGF decreased in B-cell lymphomas (P < 0.01), suggesting a possible predictive role in this group of dogs.

Comparison of 2- and 3-category histologic grading systems for predicting the presence of metastasis at the time of initial evaluation in dogs with cutaneous mast cell tumors: 386 cases (2009–2014)

OBJECTIVE To compare the Kiupel (2 categories) and Patnaik (3 categories) histologic grading systems for predicting the presence of metastasis at the time of initial examination in dogs with cutaneous mast cell tumors (MCTs). DESIGN Retrospective case series. ANIMALS 386 client-owned dogs with cutaneous MCTs. PROCEDURES Medical records of dogs with newly diagnosed, histologically confirmed cutaneous MCTs that had undergone complete clinical staging were reviewed for clinical and histopathologic data. RESULTS All Patnaik grade 1 MCTs (n = 52) were classified as Kiupel low-grade MCTs, and all Patnaik grade 3 MCTs (43) were classified as Kiupel high-grade MCTs. Of the 291 Patnaik grade 2 MCTs, 243 (83.5%) were classified as Kiupel low-grade tumors, and 48 (16.5%) were classified as Kiupel high-grade MCTs. Dogs with Patnaik grade 3 MCTs were significantly more likely to have metastases at the time of initial examination than were dogs with grade 1 or 2 MCTs (OR, 5.46), and dogs with Kiupel high-grade MCTs were significantly more likely to have metastases than were dogs with Kiupel low-grade MCTs (OR, 2.54). However, 3 of 52 (5.8%) dogs with Patnaik grade 1 tumors, 48 of 291 (16.5%) dogs with Patnaik grade 2 tumors, and 44 of 295 (14.9%) dogs with Kiupel low-grade tumors had metastatic disease. CONCLUSIONS AND CLINICAL RELEVANCE Findings indicated that in dogs with cutaneous MCTs, prognostication should not rely on histologic grade alone, regardless of grading system used, but should take into account results of clinical staging.