Papillary neoplasms of the endolymphatic sac and mucosal lining of the pneumatic spaces of the temporal bone: Role of imaging

Primary adenomatous and adenocarcinomatous lesions of the temporal bone are rare tumors. Primary low-grade papillary adenocarcinomas of the endolymphatic sac origin were first reported by Heffner. These lesions, which are referred to as “Heffner tumors,” are slow-growing, bone-destructive infiltrating tumors. Owing to the local bone destruction (usually centered at posterior petromastoid plate), the general consensus favors the endolymphatic sac as being the origin of these tumors. However, controversies regarding the cellular origins of adenomatous tumors of the temporal bone have been reported. Mafee and Shah reported a unique case in which histology was identical to papillary adenocarcinoma of endolymphatic sac in which the sac and duct showed normal findings on magnetic resonance images, which were confirmed on surgery. Computed tomography and magnetic resonance imaging are excellent imaging methods for evaluation of normal and anomaly of the vestibular aqueduct and endolymphatic duct and sac and for the diagnosis of these endolymphatic tumors. This article reviews computed tomography and magnetic resonance imaging characteristics of adenocarcinomatous tumors of temporal bone. This report also concerns a unique case of a papillary adenocarcinoma of presumed endolymphatic sac in a 12-year-old child, in which tumor replaced almost the entire petromastoid resulting in a markedly egg-shell appearance of the bone. To the best of our knowledge, this is the youngest child with papillary endolymphatic sac tumor reported.