Green iguanas are arboreal lizards, common as pet animals and in captivity. Knowledge of neoplasms in iguanas is scarce, and a challenge to their prevention, treatment, and prognosis. A captive green iguana showed a pigmented nasal exophytic neoplasm. Tumor cells were spindle-shaped to epithelioid with a variable amount of dark-brown or black granular melanin within the cytoplasm, and also presented cytoplasmic positivity for Melan-A and S100. Transmission electron microscopy evidenced intracytoplasmic melanosomes and premelanosomes and provided a definitive diagnosis of a nasal melanophoroma. Full characterization of the clinicopathological and ultrastructural features of the melanophoroma may contribute to the limited knowledge concerning cutaneous neoplasms in green iguanas.
