T- and B-cell lymphomas in 2 captive green tree pythons.

Two captive 19-y-old green tree pythons (Morelia viridis), a male and a female, were diagnosed with lymphoma. At autopsy, the female was in poor body condition and had an extensive subcutaneous soft tissue mass along the ribs. The mass was composed of numerous neoplastic round cells that were also present in the liver and spleen and within blood vessels. Neoplastic cells had marked, diffuse membranous-to-cytoplasmic immunolabeling for CD3, consistent with disseminated leukemic T-cell lymphoma. The male had a history of chronic spinal deformities and was in poor body condition. All examined organs contained variable numbers of neoplastic round cells with moderate-to-marked nuclear-to-cytoplasmic immunolabeling for PAX5, consistent with B-cell lymphoma. Here we describe 2 distinct immunophenotypes of lymphomas, including a B-cell neoplasm that has not been reported previously in snakes, to our knowledge. Our 2 cases highlight the potential value of CD3 and PAX5 immunohistochemical markers in ophidians and expand the spectrum of neoplastic diseases documented in reptiles. Understanding the clinical significance of lymphoma in snakes, including its potential impact on prognosis and challenges in management, is critical to refining therapeutic approaches in captive reptile care.