LAUSR

Ocular neoplasms represent 10% of all equine neoplasms and ocular squamous cell carcinoma (OSCC) is the most common one. This report describes the clinical presentation, laboratory, ultrasonography, postmortem, histopathology and immunohistochemistry findings of a mixed ocular neoplasm in a 10-year-old draft mare. The mare had a one-year history of left ocular mass. Complete destruction of the left eye with loss of vision was observed. A large ulcerated mass oozing blood replaced the left eye. Left parotid lymph node was swollen and had a sinus tract discharging pus. Ultrasonography revealed absence of all intraocular structures, several lobular echogenic tissues and several hyperechoic areas of ossification with acoustic shadowing. Color Doppler scanning revealed numerous neovascularization all over the tumor, particularly along the periphery. The neovascularization demonstrated mainly arterial with few mixed blood flow signals. The amplitude of systolic and diastolic blood flow was markedly increased. Enucleation was decided but the mare died just after examination. The ocular mass was excised and its weight was 390 g. Postmortem examination revealed no distant metastasis in all internal organs. Histopathology confirmed OSCC mixed with fibrosarcoma and associated with cartilaginous and osseous metaplasia. The neoplastic cells gave positive nuclear p53 immunoreactivity. The left parotid lymph node revealed metastasis. Despite the unsuccessful outcome in this particular case, this report documents a mixed eye neoplasm, highlights the ultrasonography and histopathology features of OSCC, and reinforces the need for early diagnosis and surgical treatment in such cases to improve the outcome and to decrease the drastic complications and mortality.