Plasma cell granuloma of the middle ear and mastoid. Case report.

We present the case of a 37-year-old man with plasma cell granuloma affecting the middle ear and mastoid. At magnetic resonance imaging scan, the lesion appeared as a homogeneously enhancing mass of soft tissue replacing the majority of the mastoid bone and causing vascular compression. After surgical resection, microscopic examination showed predominantly plasmacytes, and histochemical studies confirmed a polyclonal origin consistent with nonneoplastic plasma cell granuloma. We believe this is the first case report of plasma cell granuloma affecting the middle ear and mastoid.