Canine lymphomatoid granulomatosis: an immunophenotypic analysis of three cases.

Three dogs had a history of multiple progressive lesions affecting the skin, subcutis or skeletal muscles. The lesions developed over a period of several months, and each case demonstrated late cardiopulmonary complications. Post-mortem examination revealed multicentric, angio-destructive, lymphohistiocytic, proliferative lesions typical of the rare disorder lymphomatoid granulomatosis. Immunohistochemical examination demonstrated variable CD3 antigen expression by the atypical cell population in two of the three cases. This provides the first evidence that canine lymphomatoid granulomatosis may be a form of atypical T-cell lymphoma similar to the comparable disorder that occurs in man.