Systemic mastocytosis in an African fat-tail gecko (Hemitheconyx caudicinctus).

A 3-year-old African fat-tail gecko (Hemitheconyx caudicinctus) suddenly became lethargic and died 2 days later. Necropsy examination revealed a submandibular mass and discolouration of the liver, kidneys and skeletal muscles of the tail. Microscopical evaluation revealed neoplastic mast cells in the skin, liver, kidneys, skeletal muscles, bones, spleen, uterus, ovaries and lungs. Exfoliative cytological, histopathological and ultrastructural features were consistent with systemic mastocytosis. Neoplastic proliferative disorders of mast cells are rare in reptiles and this is the first report of mast cell neoplasia in geckos.