Plasma cell tumors are lymphoid neoplastic proliferations of B cells. Multiple myeloma is the disseminated type of this disorder, while localized forms of plasma cell neoplasms are solitary plasmacytoma of bone that is observed as centrally localized in bones, and extramedullar plasmacytoma (EMP) that develops in soft tissues. EMP of the head and neck region is a rare malignant tumor comprising approximately 3% of all plasma cell tumors, and approximately 0.4% of all head and neck malignancies; among them, plasmacytoma of the maxilla is extremely rare. The authors present a case of a patient affected by an EMP of the maxilla simulating a maxillary radicular cyst comparing our results with the recent literature. EMP entity requires a meticulous overview of the patient by the specialist and overall the control of any signs or symptoms of systemic diseases, a fact that would mark a dramatic change in the treatment and prognosis for the patient.