Extraosseous Plasmacytoma

**Semantic type:** Neoplastic Process

**Definition:** A localized malignant neoplasm arising in an extraosseous site. It is composed of clonal (malignant) plasma cells forming a tumor mass. It most frequently involves the oropharynx, nasopharynx, sinuses, and larynx.

**Synonyms:** - Extramedullary Plasmacytoma - Extraosseous plasmacytoma - Plasmacytoma, extramedullary