Solitary Plasmacytoma Mimicking Periapical Lesion in Maxillary Teeth: A Case Report.

This article reports a rare case of solitary bone plasmacytoma in the maxilla of a 76-year-old female patient diagnosed at an early stage. The lesion initially mimicked an endodontic infection with a sinus tract associated with teeth #22 and #23. Despite conventional endodontic treatment, no clinical improvement was observed. The patient was referred for biopsy, and histopathological analysis revealed a proliferation of plasmacytoid cells with atypia and intense leukocytic infiltrate. Immunohistochemistry confirmed monoclonality compatible with plasmacytoma. Further systemic investigation excluded multiple myeloma, leading to the final diagnosis of solitary plasmacytoma. The patient underwent 20 radiotherapy sessions totaling 40 Gy and remains clinically stable under multidisciplinary follow-up. This case highlights the importance of considering non-endodontic pathologies in persistent periapical lesions. Early recognition of plasmacytoma is crucial, as it may represent an initial manifestation of multiple myeloma, emphasizing the endodontist's role in accurate diagnosis and timely referral.