Figure 20.9.

Fibromatosis in a free-ranging gray squirrel.

(A) Multifocal, variably sized dermal plaque-like fibromas (coalescing areas of dermal thickening and alopecia) are present throughout the skin (B) The epidermis is severely thickened and there is dermal inflammation. (C) Numerous epithelial cells contain intracytoplasmic eosinophilic inclusions and are undergoing ballooning keratinocyte degeneration. Lymphocytic inflammation is present in the underlying dermis.

(Part A: Photo Courtesy of J. Landolfi, University of Illinois Zoological Pathology Program; Part C: Courtesy of D. Campbell, Canadian Wildlife Health Cooperative Ontario-Nunavut)