Aggressive papillary tumor of the middle ear: a true entity or an endolymphatic sac neoplasm?

Aggressive papillary tumors of the middle ear are rare, and their true origin is not clear. We describe the clinical, radiologic, genetic, and histopathologic features of a papillary epithelial tumor filling the middle ear of a 68-year-old woman. Imaging revealed no evidence of petrous temporal bone apex involvement, nor did genetic studies demonstrate the von Hippel-Lindau mutation. A literature search revealed 24 previously reported cases of such a papillary epithelial tumor of the middle ear. All except 2 cases demonstrated apical petrous temporal bone invasion on imaging, and it has been suggested that they arose from a primary endolymphatic sac tumor, which has a similar papillary epithelial histology. Substantial numbers of cases of papillary epithelial tumors involving the middle ear are reported to be associated with von Hippel-Lindau disease, as are known cases of endolymphatic sac tumor. This is the third reported case of papillary epithelial tumor of the middle ear that does not show apical petrous temporal bone invasion on imaging, suggesting that such neoplasms do not always arise from a primary in the endolymphatic sac.