Plasmacytoma : Nasopharynx
Extraosseous or extramedullary plasmacytomas are solitary plasma cell neoplasms that involve sites other than bone or bone marrow. They are biologically distinct from multiple myeloma and solitary plasmacytoma of bone and may in fact be related to marginal zone lymphomas. They make up less than 5% of plasma cell neoplasms. The median age at presentation is about 55 years which is 10 years younger than that for multiple myeloma. There is a strong male predominance. Locations: Almost 75% of extraosseous plasmacytomas involve the upper respiratory tract (nasopharynx, maxillary sinus, oropharynx, and larynx). However, they can occur virtually anywhere, including salivary glands, lymph nodes, breast, thyroid, gastrointestinal tract, central nervous system, and other sites. The case presented here involved the nasopharynx. The image shows sheets of plasma cells with varying degrees of differentiation beneath the squamous mucosa.