Head and Neck Extramedullar Plasmacytoma

This study aimed to contribute to the literature by sharing experience of head-neck extramedullary plasmacytoma (EMP), which are rarely seen.

A total of 11 patients treated for head and neck region EMP between 2000 and 2023 were screened retrospectively.

The 11 patients comprised 9 men and 2 women with a mean age of 55.1 ± 16.2 (range, 16-74) years. The most affected regions were seen to be the sinonasal tract, larynx, and tonsils. In the histopathological examination, plasma cells had a mature or anaplastic appearance, and one of the kappa and lambda light chains was positive and the other was completely negative. The serum electrophoresis and bone marrow flow cytometry results were negative. Of the patients with confirmed EMP diagnosis, 8 were treated with radiotherapy (RT) alone, 1 patient with maxillectomy, and 1 patient endoscopic sinus surgery followed by RT. RT was applied at a dose of 44 to 50 Gy for 22 to 25 sessions. In 1 patient, RT and chemotherapy were applied together.

In cases presenting with a submucosal, destructive tumor in the head and neck region, especially in the sinonasal region, EMP should be kept in mind. When histopathological results are confirmed, a differential diagnosis from multiple myeloma (MM) is required. Flow cytometry is of guidance in the differentiation of EMP from extranodal lymphoma. However, it should be noted that the effect of RT may be less in EMPs originating from the paranasal sinus compared with other anatomic regions, and surgery may be required before or after RT. A radiation dose of 45 Gy is sufficient for local control. Patients require long-term follow-up, as there is a possibility of EMP transforming to MM.