CD3 and CD20 co-expression in a case of canine peripheral T-cell lymphoma with prominent cardiac and peripheral nerve involvement

Abstract

An 8-y 9-mo-old male Pug dog was presented because of anorexia, hindlimb ataxia, vomiting, and progressive weight loss. Clinical examinations revealed atrophic hindlimb muscles with decreased postural reaction, enlargement of the cardiac silhouette and megaesophagus on radiograph, and reduced cardiac contractility on ultrasonography. The dog died 10 d after the initial examination, and an autopsy was performed. Grossly, the heart was enlarged, with multifocal-to-coalescing extensive plaque-like areas of discoloration on the epicardial surface. On cross-section, the ventricles were moderately dilated, and discoloration extended into the myocardium. Peripheral lymph nodes were of normal size. Histologically, atypical lymphoid cells replaced the myocardium and also extensively infiltrated peripheral nerve bundles in various organs. With immunohistochemistry, the neoplastic cells exhibited strong immunoreactivity for CD3 and CD20, and were negative for CD8, granzyme B, CD79α, and Pax5. Double-label immunofluorescence confirmed co-expression of CD3 and CD20 by the neoplastic cells. Molecular clonality analysis presented a clonal T-cell receptor gamma gene rearrangement. The case was diagnosed as a CD3+/CD20+ peripheral T-cell lymphoma with prominent cardiac and peripheral nerve involvement, indicating neurolymphomatosis.

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

“…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. Conversely, B-cell lymphomas with aberrant CD3 expression have not been reported in dogs.…”

Co-Expression of T- and B-Cell Markers in a Canine Intestinal Lymphoma: A Case Report

“…In the present case, as in most of those already described [ 9 , 10 , 20 ], the definitive diagnosis of T-cell lymphoma required the identification of clonal rearrangement for gamma T-cell receptors (TCRγ) using the PARR technique. This only differs in one studied case of nodal lymphoma in which the same pattern of immunostaining was seen despite having clonal rearrangements of a similar amplitude of both T- and B-cell receptors (cross-lineage rearrangement), when applying the molecular method for the diagnosis; in this particular case, the molecular result led to the final classification of CD3+ CD20+ anaplastic lymphoma [ 11 ].…”

“…Co-expression of CD3 and CD20 confirmed by immunohistochemistry is rare and has been described in only a few cases of canine T-cell lymphomas, such as cutaneous, intestinal, nodal, and peripheral lymphomas with infiltration of the heart and peripheral nerves [ 9 , 10 , 11 , 20 ]. Double lymphoid labelling has also been described in a cat, but in a B-cell lymphoma with expression of CD3, identified by clonality tests [ 21 ].…”

Characterization of CD3+/CD20+ canine large-cell lymphoma

“…19 The CD3+/CD20+ phenotype has been described in a small number of case reports spanning a few different types of lymphoma, including enteropathy-associated T-cell lymphoma, anaplastic lymphoma, and cutaneous epitheliotropic T-cell lymphoma. 2,9,[15][16][17]26 Despite these publications, understanding of CD3+/CD20+ LCL in dogs remains extremely limited.…”