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Lymphoma has been described in individual cases for goats but not systematically characterized in a larger cohort. This study aimed to subtype caprine lymphoma based on topographic and subgross distribution, immunophenotype, and cellular morphology following the World Health Organization classification system for hematopoietic tumors in domestic animals. Fifteen caprine lymphoma cases were assessed with 6 submitted as biopsy and 9 for postmortem examination. Goats were predominantly young adult (median 3 years) and dwarf breeds (Pygmy and Pygora). The sexes were similarly represented. Nuclear size was measured relative to red blood cells (RBCs) and then adjusted for species-specific differences and designated small (<3× RBCs), intermediate (3-4× RBCs), or large (>4× RBCs). Using immunohistochemistry, 11 of 15 (73%) goats had T-cell lymphoma (TCL; CD3 positive, CD79α negative) and 4 of 15 (27%) had B-cell lymphoma (BCL; CD79α positive, CD3 negative). A multicentric distribution was most common. TCL generally involved the thoracic cavity and/or neck, suggestive of thymic origin or homing. TCLs were further classified as lymphoblastic lymphomas (3/11; 27%), large granular lymphocyte lymphoma (1/11; 9%), diffuse small lymphocytic lymphomas (3/11; 27%), or peripheral/mature T-cell lymphoma (PTCL) not otherwise specified (4/11 [36%], of which 3 were high grade and 1 intermediate grade). In 1 goat with PTCL, lymph nodes had either paracortical expansion or diffuse infiltrates suggesting transition from nodular to diffuse PTLC. BCLs were classified as diffuse large B-cell lymphoma (2/4; 50%) or B-cell lymphocytic lymphoma intermediate type (2/4; 50%). In contrast to dogs and horses, lymphomas in goats are predominantly TCL and frequently involve the mediastinum.

Malignant lymphoma was diagnosed in 42 rhesus macaques (Macaca mulatta) and 3 stumptail macaques (M. arctoides) between February 1969 and December 1977. The distribution of tumor masses in the tissues of individual animals varied widely. Solitary tumor masses were present in 14 animals and multiple masses in the remaining 31 animals. Visceral lymph nodes, gastrointestinal tract, heart, and kidneys were most commonly affected. Peripheral lymph nodes were rarely involved. Most malignant lymphomas were of an undifferentiated cell type, although tumors of histiocytic, lymphocytic, poorly differentiated, and mixed lymphocytic and histiocytic cell types were also observed. Concurrent bacterial and/or viral infections were evident in 30 of the 45 macaques with malignant lymphoma. Amyloidosis was present in 9 animals. This high incidence of malignant lymphoma suggested that their immune responses were abnormal. The development of malignant lymphoma in the macaques may have been secondary to or enhanced by immunodeficiency.

Malignant lymphomas have been found in pikes (Esox lucius L.) caught in the eastern part of the Baltic Sea. The frequency of the disease has increased in recent years. Three different histological types of malignant lymphoma are described in 32 pikes: poorly differentiated diffuse lymphocytic lymphoma, mixed (histiocytoid-lymphocytic) diffuse lymphoma and undifferentiated (anisomorphic) diffuse lymphoma.