Canine Lymphomas

Abstract

Canine lymphoma is the neoplasm most often treated by chemotherapy, yet there are few data to correlate response to therapy with its different subtypes. This study is based on biopsy specimens from 992 dogs for which lymphoma was the clinical diagnosis. All cases were phenotyped by immunohistochemistry for CD3 and CD79alpha. Cases with histiocytic proliferation were evaluated immunohistochemically for CD18. Clonality was verified in 12 cases by polymerase chain reaction (PCR). Survival (event time) data and complete survival information (cause of death or time to last follow-up) were available on 456 dogs. Additional covariate information when available included size, age, sex, phenotype, stage and grade of lymphoma, mitotic index, and treatment protocol. Because of the many subtypes of B-and T-cell lymphoma, the cases were grouped into 7 diagnostic categories: (1) benign hyperplasia; (2) low-grade B-cell; (3) high-grade B-and T-cell; (4) low-grade T-cell; (5) centroblastic large B-cell of all mitotic grades (subdivided by clinical stage); (6) immunoblastic large B-cell of all mitotic grades, and (7) high-grade peripheral T-cell. Grouping was determined by histological grade (based on mitotic rate/400Â field, with low-grade 0-5, intermediate 6-10, and high-grade >10) and stage for survival function estimation. No association with survival was found for size (based on breed of dog) or sex. All diagnostic categories of indolent or low-grade type had low mitotic rates, whereas those with clinically high grades had high mitotic rates. The diagnostic category with the most cases was centroblastic large B-cell lymphoma. Compared with dogs in this largest represented group of lymphomas, dogs with high-grade lymphomas had significantly higher mortality rates, and dogs with low-grade T-cell lymphomas had significantly lower mortality rates. Treatments for high-, intermediate-, and low-grade lymphomas were divided into 4 groups: absence of treatment, chemotherapy with or without hydroxydaunorubicin, and only prednisone. Dogs with low-grade T-cell (T-zone) lymphomas had the longest median survival (622 days), whereas the shortest median survival was in dogs with T-cell high-grade (peripheral T-cell) subtype (162 days). The dogs with centroblastic large B-cell lymphomas had a median survival of 127 days with low stage, 221 days with intermediate stage, and 215 days with advanced stage. Dogs with T-zone lymphoma were probably diagnosed in later stages of disease because of the lack of signs associated with progression. As with human lymphomas, a histological diagnosis with immunophenotyping is a minimal requirement for diagnosis of a specific subtype.

Dissecting the Regulatory Microenvironment of a Large Animal Model of Non-Hodgkin Lymphoma: Evidence of a Negative Prognostic Impact of FOXP3+ T Cells in Canine B Cell Lymphoma

“…However, although FNAs are still the cornerstone of lymphoma diagnosis in canine patients and serve an important triaging role in people with lymphadenomegaly by virtue of their ease of procurement [58]–[60], solid tissue biopsies are considered the gold standard for diagnosis of human patients, allowing a detailed tissue architectural classification of lymphoma subtypes [1], [2]. Recent years have seen an increasing recognition of the diagnostic and prognostic value of histopathological subtypes of lymphoma in dogs [56], [61], [62], which generally show remarkable similarity to those of human patients [51], [55], [63].…”

Clasificación Histopatológica de Linfomas Caninos en la Casuística del Laboratorio de Patología Veterinaria de la Universidad Nacional Mayor de San Marcos (1996-2012)

“…En cuanto al pronóstico de supervivencia, los últimos estudios de importancia histopatológica determinaron que perros que padecían linfomas con un índice mitótico mayor de 20 mitosis/400x sobrevivían 33 días, mientras aquellos con índice mitótico menor de 20 mitosis/400x sobrevivían 188 días en promedio (Valli et al, 2013). En el país, esta enfermedad se suele diagnosticar únicamen-te como «linfoma», basado en el diagnóstico citológico.…”

“…En el país, esta enfermedad se suele diagnosticar únicamen-te como «linfoma», basado en el diagnóstico citológico. Valli et al (2013), basados en la clasificación de la OMS, clasificaron 992 casos de linfoma encontrando las siguientes frecuencias: linfoma difuso de células grandes B (39.3%), linfoma de la zona marginal (6.5%), linfoma T periférico inespecífico (13.6%), linfoma de la zona T (11.2%), linfoma linfoblástico de células precursoras B/T (4.8%), linfoma de células del Manto (1.6%) y linfoma folicular (0.3%), haciendo un total de siete tipos de linfomas; en tanto que en el presente estudio se logró clasificar seis tipos histológicos de 12 tipos de linfomas estandarizados.…”

“…Estos esquemas se basan, usualmente, en la aplicación de agentes paliativos como la doxorrubicina, L-asparaginasa, vincristina, ciclofosfamida, clorambustilo y prednisona. Sin embargo, estudios más recientes (Valli et al, 2013) han demostrado que el linfoma se debe tratar de acuerdo a determinadas características histológicas como la morfología e índice mitótico (Valli et al, 2006), que permite predecir el tiempo de supervivencia y la respuesta al tratamiento empleado. Es necesaria la selección de protocolos específicos de los tipos individuales de linfoma con el objetivo terapéutico más cercano al tratamiento curativo, y la adaptación probable de tratamientos de uso en medicina humana, debido a que estudios genéticos en mamíferos indican que los mismos tipos de linfoma en humano y en el canino responden a un similar tipo de terapia (Moore et al, 1995).…”

B‐cell lymphoblastic lymphoma of the nictitating membrane as the first presenting sign in a 2‐year‐old Springer Spaniel

“…B‐cell lymphoblastic lymphoma (B‐LBL) is a precursor subtype of lymphoma that accounts for 1.8%‐2.4%3, 4 of all canine lymphomas.…”