Abstract:
Multiple myeloma is a rare, systemic proliferation of neoplastic plasma cells. A case was
reported in an 11-year-old male captive lion (Panthera leo) at the National Zoological Gardens of
South Africa, Pretoria. The classic features of symptomatic multiple myeloma were all evident
in this case; namely osteolytic lesions, monoclonal gammopathy in the serum with excretion
of monoclonal proteins in the urine, neoplastic plasma cells in the bone marrow and associated
renal failure and anaemia. In addition, similar to the common pattern of this disease in domestic
felids, at least three extramedullary tumours were found and several organs were infiltrated
by neoplastic plasma cells. The cytoplasm of approximately 50% of the neoplastic round cells,
including a few giant myeloma cells, stained weakly to strongly using immunohistochemical
stains for B-lymphocytes (CD79a). The normal haematological parameters and lack of any
osteolytic lesions in the lion at the time of the first evaluation suggest that the primary
neoplastic cells could have originated from one of the extramedullary tumour sites. Only
two cases of multiple myeloma have previously been reported in captive wild felids. To the
authors’ knowledge, there are no case reports of multiple myeloma in lions.
