When plasmacytoma defies expectations: An unusual maxillary presentation with mixed imaging features in a young patient.

Plasmacytoma of the maxilla in adolescents is exceedingly rare and represents a diagnostic challenge, particularly when associated with atypical imaging features that may mimic aggressive maxillofacial tumors. We report the case of a 17-year-old female presenting with a progressively enlarging painless right lateronasal swelling. Computed tomography revealed a large maxillary lesion with an unusual mixed osteolytic-osteosclerotic pattern, including intralesional mineralization and multiple osteolytic lacunae. Histopathological and immunohistochemical analyses confirmed a monoclonal plasma cell neoplasm consistent with solitary extramedullary plasmacytoma, while systemic evaluation excluded multiple myeloma. The patient underwent radiotherapy (45 Gy), achieving complete remission with no recurrence at 21 months. This case highlights an uncommon imaging phenotype and a potential diagnostic pitfall, emphasizing the importance of imaging-pathology correlation for accurate diagnosis and optimal management.