Differences between disseminated idiopathic spinal hyperostosis and spondylosis deformans found on magnetic resonance imaging contribute to an increased differentiation between the two entities. Clinically relevant lesions in association with disseminated idiopathic spinal hyperostosis were rare compared to those seen with spondylosis deformans.

A 5-year-old cat developed a recurrent haematoma in the right hindlimb after receiving an intramuscular injection. Cold packs and a compressive bandage were applied without success. The haematoma resolved initially but recurred twice within a week after conservative treatment. Contrast computed tomography was performed after the second recurrence. A large cavernous lesion was found craniolateral to the right stifle. The lesion was removed surgically. No recurrence occurred during a 5 month follow-up. On histopathology the lesion was characterised as a chronic expansive haematoma. To our knowledge, this type of lesion has not previously been described in a small animal.