Composite lymphoma of concurrent T zone lymphoma and large cell B cell lymphoma in a dog

Abstract

BackgroundEvolution of indolent to aggressive lymphoma has been described in dogs but is difficult to distinguish from the de novo development of a second, clonally distinct lymphoma. Differentiation of these scenarios can be aided by next generation sequencing (NGS)-based assessment of clonality of lymphocyte antigen receptor genes.Case presentationAn 8-year-old male intact Mastiff presented with generalized lymphadenomegaly was diagnosed with nodal T zone lymphoma (TZL) based on cytology, histopathology, immunohistochemistry and flow cytometry. Thirteen months later, the dog re-presented with progressive lymphadenomegaly, and based on cytology and flow cytometry, a large B cell lymphoma (LBCL) was diagnosed. Sequencing-based clonality testing confirmed the de novo development of a LBCL and the persistence of a TZL.ConclusionsThe occurrence of two distinct lymphoid neoplasms should be considered if patient features and tumor cytomorphology or immunophenotype differ among sequential samples. Sequencing-based clonality testing may provide conclusive evidence of two concurrent and distinct clonal lymphocyte populations, termed most appropriately “composite lymphoma”.

Flow Cytometry in the Diagnosis of Canine B-Cell Lymphoma

“…Finally, the multiparametric approach of FC is extremely useful also to identify rarer cases of two coexisting neoplasms, such as T-zone lymphoma and BCL (35)(36)(37). An example is shown in Figure 3, where both BCL and TZL populations are shown at diagnosis, at the end of CHOP chemotherapeutic protocol, and at relapse of BCL.…”

CD3-CD20–positive nodal lymphoma with cross-lineage rearrangement in a dog

“…Co-expression of CD3 and CD20 is rarely observed in canine lymphoma and is described only in cutaneous epitheliotropic T-cell lymphomas 4 and intestinal T-cell lymphomas. 7,9 Also, one dog has been reported with CD3-CD20 peripheral T-cell lymphoma infiltrating the heart and peripheral nerves. 8 All the described cases had a clonal TCRγ gene rearrangement assessed by PARR, and a diagnosis was given of T-cell lymphoma expressing aberrant CD20 immunophenotype.…”

Use of immune repertoire sequencing to resolve discordant microscopic and immunochemical findings in a case of T cell-rich large B cell lymphoma in a young dog

“…To resolve these conflicting findings, clonality testing and immune repertoire sequencing were performed on liver and ascites samples [ 1 ] [see Additional file 1 for materials and methods]. Briefly, DNA was extracted from cytological preparations of the hepatic aspirate and abdominal fluid.…”

“…Lymphoma encompasses diverse neoplastic entities characterized by clonal proliferations of lymphocytes. Similar to humans, multiple types of lymphoma have been described in the dog, but more than one type of lymphoma is rarely found concurrently within a patient [ 1 – 3 ]. Classification schemes for lymphoma are based on location, histomorphology and immunophenotype, and help predict progression and response to therapy [ 4 ].…”