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Thymoma‐associated lymphocytosis in a dog
Author(s) -
Burton Andrew G.,
Borjesson Dori L.,
Vernau William
Publication year - 2014
Publication title -
veterinary clinical pathology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.537
H-Index - 51
eISSN - 1939-165X
pISSN - 0275-6382
DOI - 10.1111/vcp.12196
Subject(s) - lymphocytosis , thymoma , immunophenotyping , pathology , t cell receptor , cd3 , cd8 , medicine , immunology , t cell , biology , antigen , immune system
A 9‐year‐old female spayed English Springer Spaniel was evaluated for a cranial mediastinal mass and lymphocytosis. Flow cytometric immunophenotyping of peripheral blood lymphocytes revealed 97% as CD 3 positive, confirming a T‐cell lineage. Additionally, T‐cell subset assessment showed 53.2% to be double‐negative T‐lymphocytes, expressing neither CD 4 nor CD 8 surface markers. The number of double‐negative lymphocytes in circulation coincided with the number of T‐cell receptor ( TCR ) γδ‐expressing T‐cells in circulation. Molecular T‐cell clonality analysis of TCR Gamma (TCRG) gene rearrangement showed a polyclonal expansion of T‐lymphocytes. Histopathology confirmed the mass to be a thymoma, supporting the diagnosis of thymoma‐associated T‐cell lymphocytosis. Resolution of the lymphocytosis after removal of the thymoma provided further evidence for this diagnosis. To the authors' knowledge, this case is only the second report of thymoma‐associated peripheral lymphocytosis in the veterinary literature, and is the first to report a confirmed thymoma‐associated peripheral γδ T‐cell lymphocytosis in a dog.