ABSTRACT
The authors describe a case of unilateral adenocarcinoma emerging from the Harderian gland, filling the right orbital cavity of a Florida Red-bellied Turtle ( Pseudemys nelsoni ). The tumour did not produce any metastasis but presented an expansive growth and led to the dislocation and protrusion of the right eyeball. Histopathological analysis revealed the presence of numerous mitotic figures in the cellular population that made up the tumour. The tumour cells completely filled the alveoli of the gland and had a nest-like structure. The authors also emphasise the importance of the differential diagnosis of this rare pathological change in turtles. Epithelial hyperplasia of the Harderian gland's duct, observed in animals suffering from vitamin A deficiency, can also lead to an enlargement of the eyelid, but in these cases the change usually involves both eyelids symmetrically. This is the first description of a Harderian gland adenocarcinoma in a Florida Red-bellied Turtle.
