A case report of T-cell lymphoma in a horse

Lymphoma is a solid neoplasm of the lymphoid organs (lymph nodes, spleen, etc.). It is the most common neoplasm of the horse’s haematopoietic system, although not common in absolute terms, and has a prevalence ranging from 1% to 3% of all tumours. It is subtyped into four anatomical forms: multicentric, alimentary, mediastinic and cutaneous. Multicentric lymphoma is the most common form and usually involves the lymph nodes and other lymphoid organs, but it can induce metastases to the liver, lungs and kidneys. The clinical signs of lymphoma are associated with the degree of organ involvement and can include aspecific symptoms such as weight loss, depression, lymphadenopathy, intermittent fever, respiratory disturbances and recurrent colic. The diagnosis of equine lymphoma requires a complete clinical examination including rectal palpation, complete blood count (CBC), extended biochemical profile, bone marrow aspirate sampling, serum electrophoresis, liver and spleen echography and finally, fine-needle aspiration (FNA) or surgical biopsy of enlarged lymph nodes or any other eventual masses occurring. Lymphoma can be classified in terms of degree of malignancy as ‘low’ (prevalence of small lymphocytes similar to those appearing in the peripheral blood) or ‘high’ (composed of large lymphoblasts, when the tumour is more aggressive). The most significant classification is based on the lymphoid cell type from which the neoplasm has originated (T- or B-cell type) (Carlson, 1996; Kelley and Mahaffey, 1998; Savage, 1998; McClure, 2000)

Man's best friend: what can pet dogs teach us about non-Hodgkin's lymphoma?

Animal models are essential for understanding lymphoma biology and testing new treatments prior to human studies. Spontaneously arising lymphomas in pet dogs represent an underutilized resource that could be used to complement current mouse lymphoma models, which do not adequately represent all aspects of the human disease. Canine lymphoma resembles human lymphoma in many important ways, including characteristic translocations and molecular abnormalities and similar therapeutic responses to chemotherapy, radiation, and newer targeted therapies (e.g. ibrutinib). Given the large number of pet dogs and high incidence of lymphoma, particularly in susceptible breeds, dogs represent a largely untapped resource for advancing the understanding and treatment of human lymphoma. This review highlights similarities in molecular biology, diagnosis, treatment, and outcomes between human and canine lymphoma. It also describes resources that are currently available to study canine lymphoma, advantages to be gained by exploiting the genetic breed structure in dogs, and current and future challenges and opportunities to take full advantage of this resource for lymphoma studies