Search

Background: Cytopathology is a minimally invasive and convenient diagnostic procedure, often used as a substitute for histopathology to diagnose and characterize lymphoma in dogs. Objectives: Assess the diagnostic performance of cytopathology in diagnosing lymphoma and its histopathological subtypes in dogs. Animals: One-hundred and sixty-one lymph node samples from 139 dogs with enlarged peripheral lymph nodes. Methods: Based only on cytopathology, 6 examiners independently provided the following interpretations on each sample: (a) lymphoma vs nonlymphoma; (b) grade and phenotype; and (c) World Health Organization (WHO) histopathological subtype. Histopathology and immunohistochemistry (IHC) findings were used as reference standards to evaluate diagnostic performance of cytopathology. Clinical, clinicopathologic, and imaging data also were considered in the definitive diagnosis. Results: Classification accuracy for lymphoma consistently was >80% for all examiners, whereas it was >60% for low grade T-cell lymphomas, >30% for high grade B-cell lymphomas, >20% for high grade T-cell lymphomas, and

T cell lymphoma (TCL) is a heterogenous group of lymphoid malignancies representing about 30-40% of all canine lymphomas and often harboring a very aggressive behavior. WHO classification identifies the majority of TCLs as peripheral TCL, but other subtypes with peculiar presentation and outcome have been recognized. This review aims to explore the use of flow cytometry for refining the diagnosis of canine TCL, putting a particular emphasis on the identification of some peculiar immunotypes, such as T zone lymphoma; on the investigation of putative prognostic markers; and on the evaluation of lymphoma stage and of the minimal residual disease.

Tumours shows aberrant DNA methylation patterns, being hypermethylated or hypomethylated compared with normal tissues. In human acute myeloid leukaemia (hAML) mutations in DNA methyltransferase (DNMT3A) are associated to a more aggressive tumour behaviour. As AML is lethal in dogs, we defined global DNA methylation content, and screened the C-terminal domain of DNMT3 family of genes for sequence variants in 39 canine acute myeloid leukaemia (cAML) cases. A heterogeneous pattern of DNA methylation was found among cAML samples, with subsets of cases being hypermethylated or hypomethylated compared with healthy controls; four recurrent single nucleotide variations (SNVs) were found in DNMT3L gene. Although SNVs were not directly correlated to whole genome DNA methylation levels, all hypomethylated cAML cases were homozygous for the deleterious mutation at p. Arg222Trp. This study contributes to understand genetic modifications of cAML, leading up to studies that will elucidate the role of methylome alterations in the pathogenesis of AML in dogs.

Published studies, taken together, suggest the existence of a single canine lymphoma entity, with a small clear cell appearance by cytological evaluation, a histopathological T-zone pattern and an aberrant CD45-negative T-cell phenotype, mostly characterized by long-term survival. We describe clinical presentation and outcome in a retrospective case series of canine small clear cell/T-zone lymphoma. Despite the reported predisposition of Golden retriever, this breed was not represented in our case series. Most dogs presented with stage V disease, whereas only few had clinical signs or peripheral cytopenias. Blood was almost always more infiltrated than bone marrow. Median survival confirmed the favourable prognosis described in literature, but a few dogs died within a short time. Also, a subgroup of dogs developed second malignancies, eventually leading to death. We did not investigate possible prognostic factors because of the wide variety in treatments, and further studies are needed to identify high-risk animals.

BackgroundChronic 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.ObjectivesThe aim of the study was to determine if the immunophenotype of neoplastic cells predicts survival in canine CLL.DesignRetrospective study.AnimalsForty-three dogs with CLL.ProceduresRecords 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.ResultsSeventeen 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.ConclusionsAlthough 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.