B-cell lymphoblastic leukaemia in a guinea-pig - a case report

In this case report, lymphoblastic leukaemia is described in a five-year-old female guinea pig. Clinical examination revealed lymphadenopathy, mainly with increased size of the popliteal lymph nodes. Lymphoblast cells were determined haematologically. Postmortem findings were hepatomegaly and splenomegaly. Histopathological examination of liver, spleen and lymph nodes revealed tumour cells of lymphoblastic type. These cells showed considerable cellular pleomorphism. The protein markers CD3 and CD20 and paired box 5 (PAX5) transcription factor were traced immunohistochemically. Immunophenotypization using PAX5 showed nuclear positivity of this marker, but CD3 and CD20 (not interspecies cross-reactivity for guinea pig) demonstrated no positive reaction in the tumour cells. CD3-positive cells were found only in guinea pig tissue sections used as control. PAX5 in guinea pigs appears as a beneficial and preferred marker for B-cell derived tumours.