Multiple myeloma in a captive lion (&lt;i&gt;Panthera leo&lt;/i&gt;)

Adrian S.W Tordiffe,Emily P Lane,Nicky Cassel,Fred Reyers

doi:10.4102/jsava.v84i1.949

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.

Highlights

Multiple myeloma is the most common of several rare myeloma-related disorders involving the malignant transformation of terminally differentiated B-lymphocytes
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); strongly stained follicular cells provided a good internal positive control since this stain has not been validated for lions
The classic features of symptomatic multiple myeloma were all demonstrated in this case, namely: osteolytic lesions; monoclonal gammopathy in the serum, with excretion of light chain proteins in the urine; neoplastic plasma cells in the bone marrow; and associated renal failure and anaemia

Summary

Introduction

Multiple myeloma is the most common of several rare myeloma-related disorders involving the malignant transformation of terminally differentiated B-lymphocytes It is classically characterised in dogs and humans by: (1) bone marrow plasmacytosis, (2) monoclonal gammopathy on serum protein electrophoresis, (3) osteolysis and (4) light-chain Bence-Jones proteinuria. Sections of all three masses, and similar masses in the liver and bone marrow (5 mm diameter), consisted of sheets of round cells with clear cytoplasmic margins, medium-sized often polar nuclei with clumped chromatin and abundant lightly basophilic cytoplasm with occasional pale peri-nuclear foci (Figure 4). Findings that may be associated with the myeloma included mild diffuse global membranous glomerulonephritis and moderate multifocal midzonal gastric metastatic mineralisation (uraemic gastropathy)

Ethical considerations

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Discussion