Retroauricular Pleomorphic Adenoma Arising from Heterotopic Salivary Gland Tissue

Abstract

Summary: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.

A Case Report of Chondroid Syringoma on the Nose in a Young Male of Middle Eastern Descent

“…6,7 Whereas the histologic appearance of apocrine CS is practically indistinguishable from pleomorphic adenoma of the salivary glands, it is notable that some cases may arise not from the cutaneous adnexae but from heterotopic rests of true salivary gland tissue. 8 The contributions of heterotopy to the incidence and anatomic distribution of CS are unclear, but the surgical literature reflects a predominant distribution of pleomorphic adenomata at heterotopic sites within the deeper tissues. 9 Proposed pathogenetic mechanisms for heterotopy include tissue dislocation and misplacement during embryogenesis 9 and alternatively true heteroplasia of precervical sinus ectoderm.…”

Cystic sellar salivary gland-like lesions

“…In an exhaustive review of 2300 pituitary autopsy specimens by Schochet et al [ 3 ] in 1974, ~ 3% of patients’ pituitary glands contain microscopic tumors of salivary gland-like tissue, and are usually asymptomatic. Interestingly, a number of other organ sites have since also been recognized to harbor these misplaced, small, heterotopic tumors of salivary gland tissue, especially in head and neck regions [ 4 , 5 ].…”