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

A 2-year-10-month-old sexually intact female fancy rat was evaluated due to acute onset neurological signs following a two-month history of lethargy and behavioural changes.
Physical exam results revealed generalised muscle atrophy. Results of neurological examination localised the lesion most likely to the right thalamus based on suspicion of left unilateral hemineglect.
The patient was euthanised due to quality of life concerns and post-mortem magnetic resonance imaging (MRI) of the brain was performed, followed by necropsy. This showed a lesion in the region of the pituitary which was T1 hyperintense to the brain, T2 isointense to white matter and hypointense on gradient echo sequences, suggestive of subacute haemorrhage.
We describe 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 at post-mortem examination.