• Extramedullary plasmacytomas (EMPs) are plasma cell neoplasms that most frequently arise along the upper airways and often do not secrete detectable amounts of M protein at the time of diagnosis. The present report describes the immunohistochemical characterization of an EMP in a young woman. The unlabeled peroxidase-antiperoxidase method was employed to demonstrate cytoplasmic immunoglobulin determinants in routinely processed, paraffin-embedded tissue. Only κ light chain and γ heavy chain determinants were found in the cytoplasm of the neoplastic plasma cells; essentially identical results were found in both initial and recurrent lesions separated by a 16-month interval. This exclusive staining of one light chain type associated with only one heavy chain represents a monoclonal staining pattern that is typical of B-cell neoplasms. Such characterization of EMPs on the basis of cytoplasmic immunoglobulin class and type may provide prognostic information analogous to the classification of multiple myeloma by immunoelectrophoresis.
(Arch Otolaryngol 1982;108:362-365)
Humphrey DM, Aufdemorte TB, Mattox DE. Immunoperoxidase Characterization of a Pharyngeal Plasmacytoma. Arch Otolaryngol. 1982;108(6):362–365. doi:10.1001/archotol.1982.00790540034009
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