Spontaneous, multicentric lymphoma in a young New Zealand white rabbit

Joint BSTP/ESTP Toxicologic Pathology Congress 2025 -- Lymphoma is described as an uncommon proliferative neoplastic finding that can affect the laboratory rabbit according to the International Harmonization of Nomenclature and Diagnostic Criteria: Nonproliferative and Proliferative Lesions of the Rabbit (INHAND). However, there are currently no reported cases in the literature. In juvenile pet rabbits, it is the most common neoplasm (occurring in individuals as young as 4 months old) and the second most common type of neoplasia in domestic rabbits overall. Lymphoma can be localized to a single tissue (spleen, thymus, skin, intestines); however, in pet rabbits, it is more commonly a disseminated neoplasm, affecting multiple tissues (lymphoid and non-lymphoid) concurrently. The most common immunotype is the B-cell lineage. This case report details the clinical findings, macroscopic, microscopic and immunohistochemical features of a spontaneous case of lymphoma in a 9.5-month-old, female New Zealand white rabbit.