Clinical, histologic, and immunohistochemical characterization of wart-like lesions on the paw pads of dogs: 24 cases (2000-2007)

Objective - To determine clinical, histologic, and immunohistochemical findings for dogs with wart-like lesions involving the paw pads. Design - Retrospective case series. Animals - 24 dogs (18 Greyhounds and 6 dogs of other breeds). Procedures - Medical records were reviewed for information on signalment, physical examination findings, concurrent disease processes, location of all lesions, and, when available, results of histologic examination of biopsy specimens. Available biopsy specimens (n=11) were submitted for immunohistochemical staining and a PCR assay to identify viral inclusion bodies. Results - In Greyhounds, most lesions involved the pads of the third and fourth digits, had a consistent histologic appearance without evidence of inflammation, were negative for papillomavirus, and had an unsatisfactory response to treatment. In other breeds, lesions often involved the pads of non-weight-bearing digits, had histologic evidence of inflammation, were positive for papillomavirus, and responded to surgical treatment. Conclusions and Clinical Relevance - Results suggested that wart-like lesions involving the paw pads of Greyhounds were a distinct clinical entity with features resembling porokeratosis plantaris discreta in humans. In Greyhounds, these lesions were not associated with an underlying viral etiology and, therefore, should not be considered plantar warts. Alternative treatments should be investigated because current treatments were generally unsuccessful in Greyhounds. Wart-like lesions of the paw pads in other breeds were often associated with papillomavirus, and surgical excision appeared curative.