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Palatal Solitary Plasmacytoma: A Case Report on Post-radiotherapy Challenges
Mayuko Yamashita1,2, Yoshihiko Kondo1, Shinya Endo3
1Department of Cell Pathology, Graduate School of Medical Sciences, Kumamoto University, Kumamoto, Japan.
Background/Aim:
Plasmacytomas are neoplastic proliferations of plasma cells, usually presenting as solitary lesions distinct from multiple myeloma (MM). Solitary plasmacytomas in the oral cavity and head and neck are very rare, with limited data on clinical course and treatment response.
Case Report:
A 78-year-old woman presented with a solitary plasmacytoma on the palate. Imaging ruled out bone or systemic involvement. Pathology showed positivity for CD138, lambda light chain, CD79a, MUM1, Ki-67 (10-15%), and amyloid deposits. Although the patient received definitive radiation therapy (50 Gy/25 fractions), residual disease remained. At the patient's request, six cycles of systemic chemotherapy with daratumumab, lenalidomide, and dexamethasone (DRd) were administered, leading to further shrinkage without complete response.
Conclusion:
This rare case of solitary plasmacytoma showed residual disease post definitive radiotherapy. In those residual tumors, close long-term monitoring is crucial.
