A series of heterogeneous lymphoproliferative diseases with CD3 and MUM1 co-expressed in cats and dogs

Abstract

Lymphoma diagnosis in dogs and cats is continually evolving as new subtypes and human correlates are being recognized. In humans, T-cell lymphomas with MUM1 expressed and plasma cell neoplasia or B-cell lymphomas with CD3 expressed aberrantly are reported only rarely. We report here a case series of tumors in dogs and cats with CD3 and MUM1 co-expressed as determined by immunocytochemistry or immunohistochemistry. Lineage was assigned for these tumors by 3 board-certified pathologists and a veterinary immunologist based on review of clinical and cellular features and the results of ancillary testing including PCR for antigen receptor rearrangements, flow cytometry, and serum protein electrophoresis with immunofixation. In cats, 7 of 7 tumors, and in dogs, 3 of 6 tumors with CD3 and MUM1 co-expressed had clonal rearrangement of the immunoglobulin gene or serum monoclonal immunoglobulin, consistent with a diagnosis of a plasma cell neoplasia or myeloma-related disorder with CD3 expressed aberrantly. Disease was often disseminated; notably, 3 of 7 feline cases had cutaneous and/or subcutaneous involvement in the tarsal area. In dogs, 3 of 6 cases had a clonal T-cell receptor gamma result and no clonal immunoglobulin gene rearrangement and were diagnosed as a T-cell tumor with MUM1 expressed. The use of multiple testing modalities in our series of tumors with plasma-cell and T-cell antigens in dogs and cats aided in the comprehensive identification of the lymphoproliferative disease subtype.

MUM1/IRF4 immunolabeling of neoplastic Langerhans histiocytes in a putative case of canine Langerhans cell histiocytosis

“…MUM1/IRF4 expression is also well documented in multiple dendritic cell subsets in people and mice 7,8 . Though it is widely used as a plasma cell marker in veterinary immunohistochemical and immunocytochemical panels, recent reports in veterinary literature also describe MUM1 immunoreactivity in canine cutaneous histiocytomas, 2 and in some canine T‐cell lymphomas 9 . This case both highlights the imperfect specificity of this marker for plasma cells and corroborates the potential for MUM1 immunoreactivity of Langerhans histiocytes as documented by Stillwell et al in canine cutaneous histiocytomas.…”

“…7,8 Though it is widely used as a plasma cell marker in veterinary immunohistochemical and immunocytochemical panels, recent reports in veterinary literature also describe MUM1 immunoreactivity in canine cutaneous histiocytomas, 2 and in some canine T-cell lymphomas. 9 This case both highlights the imperfect specificity of this Langerhans cell precursors. 10 BRAF V600E mutation is one such mutation that is identified in 30-40% of human LCH cases and has been suggested as a prognostic factor for high-risk disease in people.…”

Immunohistochemical identification of T and B lymphocytes in formalin-fixed, paraffin-embedded tissues of 53 avian species using commercial antibodies

“…Lymphoma cells that co-express T and B cell antigens have been reported in humans, dogs, cats, and birds in the genera Amazona sp. and cockatiel [ 7 , 14 , 22 , 29 , 38 , 41 , 43 , 44 , 45 , 57 , 58 , 60 ]. However, the possibility of unexplained nonspecific binding of anti-CD20 and anti-BLA36 antibodies to the T cell area cannot be ruled out.…”

Cutaneous Plasmacytoma with Systemic Metastases in a Cape Serotine Bat (Laephotis capensis)

“…One study found the most frequent site of origin to be the skin [ 5 ], whilst other reports suggested oral plasmacytomas are the most common [ 1 , 2 , 3 ]. The incidence of plasmacytomas in cats is much lower, and the literature mostly consists of case reports of a single animal [ 7 , 8 , 9 , 10 , 11 ], although there are some studies with larger sample numbers ( n = 7–11) [ 12 , 13 , 14 , 15 ].…”