Localized oral histiocytic sarcoma in a leopard gecko (Eublepharis macularius)

A two-year-old female leopard gecko presented with a mass in the oral cavity with apparent exophthalmos. Despite medical management, the animal died. Grossly, the firm and tan to white mass extended from the oropharyngeal region to the external surface overlying the cornea of the left eye. Histologically, the mass was a poorly-demarcated, densely cellular, invasive neoplasm. The neoplasm was composed of solid sheets and interlacing bundles of round, polygonal, and short spindle-shaped cells. Immunohistochemically, the neoplastic cells were positive for Iba-1 and CD204. These findings were consistent with a localized histiocytic sarcoma. This is the first documentation of the gross, histopathological, and immunohistochemical features of localized histiocytic sarcoma in a leopard gecko.