Plaques, Nodules and Eosinophilic Granuloma Complex Lesions

Abstract

Plaques and nodules, including the lesions belonging to the eosinophilic granu-loma complex (EGC), are common in cats. Plaques and nodules are caused in most cases by infectious, allergic, metabolic or neoplastic diseases. Clinical presentations of plaques and nodules and their preferential localization in selected feline diseases are described, together with useful hints coming from signalment and history. A feline-specific group of plaques or nodules, known as the EGC, and its specific features are also addressed in this chapter. EGC traditionally comprises eosinophilic plaque (EP), eosinophilic granuloma (EG) and lip (indo-lent) ulcer (LU). The diagnostic approach to plaques and nodules starts with the cytological examination, which may help the clinician to differentiate between the neoplastic and the inflammatory nature of the lesion. Histopathological examination is required to make or to confirm the diagnosis, and further testing is usually suggested by the histopathological diagnosis. Definitions A plaque is a flat elevation of the skin greater than 1 cm of diameter, and its size is, by definition, larger than its height. Plaques often form from a papule increasing in size or by coalescence of multiple papules.