Rhabdomyoma of the ear pinna in four cats

Four cases of rhabdomyoma of the ear pinna in white eared adult cats are reported. The lesions were raised, non-ulcerated, red-purple, discoid nodules on the convex surface of the pinna. Histologically, the nodules consisted of interlacing bundles of spindle-shaped cells that occasionally had cross striations. Lesions have not recurred 2-3 years following surgical excision. Although a specific cause for tumour development was not found, the similarity among these cases suggests that common factors played a role in the development of the lesions.