EXTRAMEDULLARY plasmacytoma is an uncommon type of tumor mostly detectable in the mucous or submucous tissues of the upper respiratory tract and the alimentary canal, the most frequent sites being the nasal cavity and the nasopharynx. The tumor is either solitary or multiple, a polypoid formation, often with ulcerative and bleeding surface. The disease belongs to a subordinate group of the plasma cell tumors, extremely rare in practice but of certain interest to pathologists, dermatologists, and otologists. Extramedullary plasmacytoma is considered an early stage of multiple myeloma. It may sometimes metastasize into adjacent bone with a respective change in the clinical symptoms to those corresponding to multiple myeloma.
The diagnosis is a microscopic one, which makes it important to do a biopsy before the treatment is begun. The histopathologic analysis alone is not sufficient, however, to determine malignancy or clinical prognostication; identification has to be based upon the site,
VAINIO-MATTILA J. Plasmacytoma of the Parotid Gland. Arch Otolaryngol. 1965;82(6):635–637. doi:10.1001/archotol.1965.00760010637016