Solitary plasmacytoma of the tonsillar site associated with actinomyces infection: the possible role of IL-6.

ExtraMedullary Plasmacytoma (EMP) is a rare plasma cell tumor. It can occur in the upper aerodigestive tract and presents as a large nodule causing local compressive symptoms. A 79-year old woman presented to Otorhinolaryngology Department with progressive hearing loss and no other symptoms. Following PET/TC examination due to the suspicion of a lymphoproliferative disease, the patient underwent tonsillectomy and the diagnosis of solitary EMP was formulated. In addition to that, the histological examination of the tonsillar tissue revealed large colonies of filamentous bacteria, showing abundant sulphur granules and Splendore-Hoeppli phenomenon; these evidences indicating the presence of a chronic Actinomyces infection. Immunohistochemical analysis demonstrated a marked IL-6 immunoreactivity of the neoplastic plasma cells. Interestingly, a marked IL-6 immunoreactivity was also found in the tissue surrounding the Actinomyces colonies. In the present study we report for the first time a solitary EMP associated with Actinomycosis. It is tempting to speculate that the unsuspected and untreated Actinomyces infection, through chronic IL-6 production, could contribute to the neoplastic transformation of plasma cells.