Retroauricular Pleomorphic Adenoma Arising from Heterotopic Salivary Gland Tissue

A 38-year-old woman is described who presented with a slowly growing mass on the posterior aspect of the left ear. Excision and histopathologic evaluation revealed a pleomorphic adenoma (PA) originating from heterotopic salivary gland tissue. Many authors have presented cases of PAs originating from ceruminous glands in the external auditory canal or of so-called chondroid syringoma originating from apocrine and eccrine sweat glands. This is the only case in the recent literature of a PA originating from a heterotopic rest of salivary gland tissue in the retroauricular region. The 3 main sources of PAs, their embryologic derivation, and treatment are described.