Rare Differential Diagnosis of Dyspnea: Extramedullary Plasmocytoma (EMP) of the Larynx-Case Report and Review of the Latest Literature of Laryngeal EMP and Laryngeal Involvement of Multiple Myeloma.

Multiple myeloma (MM) of the larynx is extremely rare. It can be either a laryngeal manifestation of a general multiple myeloma or it can occur as a primary laryngeal mass, which is then called extramedullary plasmocytoma (EMP). We present the case of an 81-year-old male patient who was admitted for dyspnea. He had a history of multiple myeloma but was in complete remission since some years. Histological and immunohistological examination of tissue samples revealed an EMP. The patient was first treated by laser surgery in order to reduce the tumor mass and secure the airway. Afterwards, he was systematically treated by radiation therapy with 60 Gy, which achieved a good response and complete remission proven by control laryngoscopy and histological examination of tissue samples taken from the former tumor area three months after laser excision. The latest literature in the field is reviewed. There were only ten cases of EMP in the larynx or laryngeal involvement of MM published within the last five years (Pubmed was searched for "larynx," "laryngeal" and "EMP," "Extramedullary Myeloma," "Multiple Myeloma," and "MM"). Due to its rarity, there are currently no evidence-based therapeutic guidelines available. For their development, multicenter studies are required.