A Morphological Study of 608 Cases of Canine Malignant Lymphoma in France With a Focus on Comparative Similarities Between Canine and Human Lymphoma Morphology

Abstract

This study reports cytomorphological, histomorphological, and immunological characterization of 608 biopsy cases of canine malignant lymphoma, with epidemiological and clinical data, collected from 7 French veterinary pathology laboratories. It compares morphological characteristics of malignant lymphoma in canines, per the updated Kiel classification system, with those reported in humans, per the World Health Organization (WHO) classification system. Of tumors described, 24.5% and 75.5% were classified as low-and high-grade malignant lymphomas, respectively. Presenting clinical signs included generalized or localized lymphadenopathy (82.4%) and extranodal diseases (17.6%) involving the skin (12.34%) and other sites (5.26%). Immunohistochemistry confirmed 63.8% B-cell (CD3-, CD79aþ), 35.4% T-cell (CD3þ, CD79a-), and 0.8% null-cell (CD3-, CD79a-) lymphomas. Most B-cell cases (38.49%) were of high-grade centroblastic polymorphic subtype; most T-cell cases (8.55%), high-grade pleomorphic mixed and large T-cell lymphoma subtypes. Some B-cell tumors showed morphologic characteristics consistent with follicular lymphomas and marginal zone lymphomas per the Revised European American Classification of Lymphoid Neoplasms and WHO canine classification systems and the WHO human classification system. Unusual high-grade B-cell subtypes included an atypical high-grade small B-cell lymphoma (0.66%), Burkitt-type B-cell lymphoma (1.64%), plasmacytoid lymphoma (0.99%), and mediastinal anaplastic large B-cell lymphoma (0.16%). Unusual T-cell subtypes included a previously undescribed high-grade canine immunoblastic T-cell type (1.15%), a rare low-grade prolymphocytic T-cell lymphoma (0.16%), and a recently described high-grade canine T-cell entity-aggressive granulocytic large-cell lymphoma (0.16%). Marginal zone lymphomas were common (10.86%); follicular lymphomas were rare (0.49%). Canine primary cutaneous malignant lymphoma subtypes were present (11.84%). There was no significant difference between B-and T-cell malignant lymphoma in regard to canine age and sex. A significant overrepresentation of Boxers (24.19%) was found for T-cell lymphomas.

Immunohistochemical detection of P-glycoprotein in various subtypes of canine lymphomas

“…Our results indicate that P-gp expression occurs in lymphomas of different histological subtype including CBL which is the most often diagnosed type of canine lymphomas (Ponce et al 2010). In human medicine P-gp expression has been observed mainly in cutaneous T-cell lymphomas (Jillella et al 2000), nasal NK/T lymphomas (Saglam et al 2008), acute lymphoblastic leukemia (ALL) (Plasschaert et al 2003), chronic lymphocytic leukemia (Jamroziak et al 2004) and DLBCL (Ohsawa et al 2005).…”

“…Histopathological diagnosis was performed on the sections stained with haematoxylin and eosin (HE). Tumors were classified according to the updated Kiel classification adapted to canine species by Ponce et al (2010).…”

Comparative oncology: what dogs and other species can teach us about humans with cancer

“…In the domestic dog, the proportions of B-and T-cell lymphomas across all dogs is estimated to be approximately 2 : 1, but the immunophenotype prevalence in individual breeds is highly variable [102]. A large study of canine lymphoma characterized 608 cases based on cytomorphological, histomorphological and immunological criteria and importantly included both epidemiological and clinical data [103]; the majority of tumours (76%) were classified as high-grade malignant lymphomas, highlighting the clinical importance of understanding both lymphoma risk and designing novel therapeutic approaches. As is the case across all breeds, approximately two-thirds of the canine lymphomas in this cohort were classified as B cell (CD3 -, CD79aþ) with one-third classified as T-cell lymphomas (CD3þ, CD79a-) [103].…”

Survivin expression in canine lymphomas in relation with proliferative markers

“…Histopathological diagnosis was performed on the sections stained with hae-matoxylin and eosin (HE) and by immunohistochemical phenotyping. Tumors were classified according to the updated Kiel classification adapted to the dog by Ponce et al (2010).…”