Epidermal growth factor-containing fibulin-like extracellular matrix 1-derived amyloidosis with fatal gastric bleeding in a Tsushima leopard cat (Prionailurus bengalensis euptilurus)

Epidermal growth factor-containing fibulin-like extracellular matrix 1 (EFEMP1)-derived amyloidosis causes gastrointestinal bleeding in humans. Amyloidosis has also been reported in the Tsushima leopard cat (Prionailurus bengalensis euptilurus) and rhesus macaque (Macaca mulatta). However, the clinical signs and lesions in humans and animals differ. A captive Tsushima leopard cat, aged 19 years, died of haemorrhage due to a gastric ulcer and a pathological analysis was performed. Amyloid was deposited in the venous walls and interstitium of the systemic organs, especially the stomach and intestines. The amyloid appeared as a weakly basophilic hyaline-like substance and stained with Congo red. Immunohistochemistry and liquid chromatography-tandem mass spectrometry revealed that the amyloid was composed of both N- and C-terminal EFEMP1 peptides. The amyloid fibrils were approximately 10 nm wide, unbranched, short and randomly arranged. The patient died from gastric bleeding caused by EFEMP1-derived amyloidosis. These findings suggest that EFEMP1-derived amyloidosis in Tsushima leopard cats has pathological features similar to those in affected humans, including amyloid deposition predominantly in the walls of veins and fatal gastrointestinal bleeding.