A 2-year-old, spayed male Bengal cat was referred to our clinic due to a mass lesion on the upper lip, as well as lower lip swelling and redness. Furthermore, well-circumscribed, raised, pink lesions were found in the oral cavity. Complete blood counts (CBC) and serum biochemistry profiles revealed no remarkable findings. Bacterial and fungal cultures of the lesion in the oral cavity were negative. Fine needle aspiration of the lesions revealed numerous eosinophils. Based on both clinical examination and cytological evaluation, the cat was diagnosed with feline eosinophilic granuloma. As an initial treatment, oral prednisolone (PDS) with cyclosporine was administered. However, the cyclosporine caused the cat to vomit. The lesion was markedly improved after 2 weeks of PDS-only therapy; this was subsequently tapered for 2 months and discontinued. However, one month later, the lesion had relapsed. The cat was then treated for one month using tacrolimus with PDS, and the clinical signs of eosinophilic granuloma gradually improved. The tacrolimus was gradually tapered for 1 month, and the PDS was gradually tapered for 4 months. There is no standard protocol for the investigation and treatment of feline eosinophilic granuloma. The cat in this report was administered immunosuppressive therapies to treat eosinophilic granuloma. This case report provides evidence the combination of PDS and tacrolimus is effective for reducing relapse in feline eosinophilic granuloma.

T:raumat ic eosinophili c granuloma(TEG) of the oral mucosa is considered to be a reactive benign lesion. which commonly manifests as an ulcer with elevated and indurated borders Clinically, this lesion simulates a malignant tumor. Histology shows a diffuse. dense, polyrnorphic, and eosinophil - rich cellular infiltra te. which extends deeply into the underlying soft t issues. A major constituent of infil trates is a population of mitotically active‘ la rge‘ atypi cal mononuclear cells. Immunohistologic evaluation of the large atypical cells has suggested a myofibroblastic 01' his tiocytic ol'igin. However, recent reports have shown that these cells are positive 1'01' CD30 antigen and it has been s llggested tha t a subset of TEG cOllld be included within the spectrum of CD30+ lymphoprolifer ative disorders. We have described 2 patients who had oral mllcosal lesions with features of TEG. ln patient 1. the lesiona l cells expressed CD3 .. CD43, LCA. Interestingly, the large cells were strongly CD30 positive. bl1t nega tive for CD68, CD45Ro‘ CD56, CD20. This case was interpreted as a CD30+ Iymphoproliferative disorder. In pa tient 2‘ t he la rge cell s showed strong posit ive for CD68, hut negative for CD30 The small lymphocytic cells ex prerssed CD3 This case was interpreted as an atypical histiocytic granuloma. Therefore, TEGs inclllde atypical histiocytic granllloma a long with the CD30+ lymphoid lesions. These findings suggested that TEG w0111d be a hete rogenous category of oral mucosal di sorders