September 2016



SLIDE A:  Signalment (JPC #2316310):  Cat

HISTORY:  This cat had a well-circumscribed, linear, ulcerated lesion along the lip margin.

HISTOPATHOLOGIC DESCRIPTION:  Mucocutaneous junction, lip:  Multifocally expanding the subepidermal connective tissue, separating hyalinized, fragmented collagen bundles and extending into the underlying skeletal muscle are numerous viable and degenerate eosinophils, admixed with fewer plasma cells, macrophages, lymphocytes, and neutrophils.  The overlying mucosal epithelium is focally extensively ulcerated and replaced by brightly eosinophilic necrotic cellular debris, degenerate neutrophils, and aggregates of 1µm cocci (serocellular crust).  The remaining adjacent mucosal epithelium is hyperplastic with acanthosis and spongiosis.  Vessels in the subepithelial connective tissue are often lined by hypertrophied endothelial cells and there is mild fibrosis.  The adjacent, less affected haired skin and dermis contains multifocal perivascular and periadnexal aggregates of primarily lymphocytes and plasma cells. Lymphatics are multifocally dilated (edema) and apocrine glands are often ectatic.  Inflammatory cells separate, surround, and occasionally replace skeletal muscle fibers which are often swollen with vacuolated sarcoplasm (degenerate), shrunken and hypereosinophilic, with loss of cross striations (necrosis), or lightly basophilic with multiple, centralized, vesiculate nuclei.  

MORPHOLOGIC DIAGNOSIS:  Mucocutaneous junction, lip:  Cheilitis, eosinophilic and ulcerative, chronic, focally extensive, marked, with lymphoplasmacytic dermatitis, and skeletal muscle degeneration and necrosis, breed unspecified, feline.

ETIOLOGIC DIAGNOSIS:  Idiopathic eosinophilic granuloma

CONDITION:  Eosinophilic granuloma complex

SLIDE B - Signalment (JPC #1953607):  Horse

HISTORY:  Tissue from a cutaneous nodule.

HISTOPATHOLOGIC DESCRIPTION:  Haired skin:  Expanding the deep dermis up to five times normal thickness; separating and surrounding collagen bundles, muscle fibers and adnexa; and extending into the panniculus carnosus are multiple individual to coalescing nodules centered on variably mineralized eosinophilic cellular debris (necrosis) and fragments of hypereosinophilic collagen fibrils.  Foci of necrotic debris are surrounded by numerous degenerate and fewer viable eosinophils and epithelioid macrophages, with fewer lymphocytes and plasma cells, and few multinucleate giant cells (Langhans and foreign body type), and are further separated and surrounded by abundant fibrous connective tissue. Viable and degenerate eosinophils and epitheliod macrophages often palisade around fragments of hypereosinophilic or hyalinized collagen (“flame figures”). Within the dermis there are few prominent lymphoid aggregates and endothelial cells are often hypertrophied (reactive). Lymphocytes, plasma cells and fewer eosinoophils infiltrate the superficial panniculus carnosus and surround myofibers.  

MORPHOLOGIC DIAGNOSIS:  Haired skin:  Dermatitis and panniculitis, nodular, eosinophilic and granulomatous, focally extensive, severe, with flame figures and mineralization, breed unspecified, equine.

ETIOLOGIC DIAGNOSIS:  Idiopathic collagenolytic granuloma

CONDITION:  Equine eosinophilic nodular disease












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