Clinical and imaging features of suspected pituitary apoplexy in a domestic rat

Abstract

A two-year-ten-month-old entire female fancy rat was evaluated for acute-onset neurological signs following a two-month history of lethargy and behavioural changes. Physical examination revealed generalised muscle atrophy. Neurological examination localised the lesion likely to the right thalamus based on suspected left unilateral hemineglect. The patient was euthanased over quality-of-life concerns, and postmortem MRI of the brain was performed, followed by postmortem examination. This showed a lesion in the region of the pituitary which was T1 hyperintense to the brain, T2 isointense to the white matter and hypointense on gradient echo sequences, suggesting subacute haemorrhage. The authors described the clinical presentation and imaging features (MRI) of suspected pituitary apoplexia secondary to a pituitary macroadenoma in an aged female rat. Of particular interest are the findings of unilateral hemineglect and blooming artefact on MRI gradient echo sequences that lead to suspicion of pituitary apoplexia confirmed on postmortem examination.