Solitary plasmacytoma (SP) is a rare malignant tumor of plasma cells with no systemic spread; however, when it disseminates and affects multiple skeletal sites, it is called multiple myeloma (MM). The etiology of solitary plasmacytoma is unknown, with two possible subtypes: solitary extramedullary plasmacytoma (EMP) and solitary bone plasmacytoma (SBP). We present a case of EMP arising as asymptomatic erythroplakia of the palate, which is rarely described in the literature. The definitive diagnosis was obtained with immunohistochemical studies, after which the lesion was subjected to excisional biopsy. At present, after two years of close follow-up, the patient has shown no signs of relapse or conversion to MM. The uniqueness of the case highlights the possibility of an atypical EMP lesion in the head and neck, thus posing a diagnostic and therapeutic challenge for physicians.