Nodular panniculitis in a cat with high alpha tocopherol concentration in serum

A 5-year-old male neutered domestic shorthair cat suffered from recurrent solitary nodules in different subcutaneous body regions. Nodules were surgically removed and each time histopathological diagnosis was fat necrosis and fibrosing to pyogranulomatous panniculitis. After the second surgery the alpha (α)-tocopherol concentration in serum of the cat was examined and the result (21 mg/L) exceeded the upper limit of the reference interval (3-11 mg/L). Vitamin E amount in diet fed solely in the past was checked as studies have shown that vitamin E amounts in food significantly influence vitamin E concentrations in serum. For comparative purposes, α-tocopherol concentrations were determined in sera of healthy control cats. Additionally, vitamin E amount in wet food from different manufacturers was analysed using gas chromatography coupled to mass spectrometry (GC-MS). The results showed that the diet did not have higher vitamin E amounts compared to other diets. All control cats had similar high serum α-tocopherol concentrations. We conclude that panniculitis can occur despite high serum α-tocopherol concentrations in cats. Further studies are needed to redefine reference values of α-tocopherol in serum of cats.