NOTE Clinical Pathology A Rare Case of Hepatic T-Cell Rich B-Cell Lymphoma (TCRBCL) in a Juvenile Dog

ABSTRACT. A 7-month-old castrated male French Bull dog was presented with vomiting, lethargy, anorexia and weight loss of 2 weeks duration. The patient’s history and clinical manifestations of suspected hepatopathy were subjected to ultrasonography, radiography, bio-chemical investigations and cytology of hepatic lesion. The cytologic impression was hepatic lymphoma, which was later confirmed by histopathology. The neoplastic cells were strongly diffusely immunoreactive for PAX5, but not immunoreactive for CD3, and B lymphocyte specific clonal proliferation was detected using by assay of antigen receptor rearrangement. Large numbers of immunoreactive mature non-neoplastic lymphocytes were admixed with the neoplastic cell population. Therefore, the immunohistochemical results were definitively consistent with a T-cell rich B-cell lymphoma (TCRBCL). This is the first description of a hepatic TCRBCL in a juvenile dog showing a poor response to aggressive chemotherapy. KEY WORDS: diffuse large B-cell lymphoma, hepatopathy, juvenile dog, lymphoma, T-cell rich B-cell lymphoma doi: 10.1292/jvms.14-0088; J. Vet. Med. Sci. 76(10): 1393–1397, 2014 Lymphoma is a malignant disorder derived from clonal proliferation of lymphoid precursor cells and is one of the most commonly diagnosed canine neoplasms [5]. Tumor cell type is an important criterion for treatment and prognosis, and lymphoma has been broadly divided into two major group