Abstract
Eosinophilic granulomas (EG) were diagnosed in four adult tigers (Panthera tigris) from three separate collections. Age at initial diagnosis ranged from 8–16 yr. All lesions were located on the hard or soft palate. The gross appearance of the lesions ranged from small flat ulcers or plaques (1x2 cm) to large pedunculated masses (6x4x4 cm) hanging into the oral cavity. Diagnosis was made via histopathologic examination of biopsy specimens. The histopathologic features in all cases were similar to those seen in domestic cats diagnosed with eosinophilic granulomas.1 In three cases, there were no clinical signs related to these lesions at the time of diagnosis. In Case 4, bleeding from the mouth and visualization of a mass during vocalizations were noted. Clinical signs coinciding with the progression of the oral lesions included inappetance, salivation, and regurgitation. In domestic cats, EGs are most often found on the thigh and are generally thought to be a result of a hypersensitivity reaction.2 Hypersensitivity to seasonal allergens was demonstrated via skin testing in Case 1. No seasonality or specific underlying hypersensitivity was noted in the other three cases.
All cats were treated with corticosteroids either orally, intramuscularly, intralesionally or via a combination of routes. Other treatments included antibiotics, chlorpheniramine, ranitidine, sucralfate, flax seed oil, and a vitamin supplement. In Case 4, corticosteroid treatment was initiated after surgical debulking of two pedunculated masses. Most lesions initially responded to corticosteroids by becoming smaller or less inflamed, but would worsen after cessation of treatment. Problems suspected to have been related to treatment included inappetance, aspiration pneumonia, hepatopathy, adrenal cortical atrophy, oral botryomycosis, and cryptococcal pneumonia.
Eosinophilic granulomas may be underreported in large felids and further investigation into their etiology and treatment is warranted.
Literature Cited
1. Fondati, A., D. Fondevila, and L. Ferrer. 2001. Histopathological study of feline eosinophilic dermatoses. Vet. Dermatol. 12:333–338.
2. Power, H.T., and P.J. Ihrke. 1995. Selected feline eosinophilic skin diseases. Vet. Clin. North. Am Small. Anim. Pract. 25:833–850.