Pathology consultation. Plasma cell tumors of the head and neck.

Neoplastic plasma cell disorders, multiple myeloma, extramedullary plasmacytoma and solitary plasmacytoma affect the head and neck with different manifestations. Multiple lytic lesions of the jaws and infrequent soft-tissue lesions characterize multiple myeloma's presence. The solitary plasmacytoma of bone is infrequent in the jaws. Wherever it occurs, it is a precursor lesion to multiple myeloma. Extramedullary plasmacytoma has several clinical and biologic forms. The most benign is the local upper airway lesion that is amenable to surgery or radiotherapy and manifests no recurrences. Approximately 40%, however, terminate in osseous and soft-tissue dissemination. The distant involvement has more characteristics of metastases than the diffuse axial skeletal involvement of multiple myeloma; to acknowledge this distribution and the apparently better prognosis, the disseminated form is called myelomatosis.