Primary cutaneous plasmacytoma (PCP) is a rare cutaneous B cell lymphoma. We report a case of PCP in a 64 year old woman presenting with a nodular lesion of the left cheek. Histologically, the lesion was composed predominately of variably maturated plasma cells with monotypic expression of lambda chain. Extracutaneous localizations of the disease had been excluded. The prognosis of PCP is better than that of the metastatic cutaneous lesion of myeloma. The main prognosis factors are the size tumor and clinical presentation (solitary, versus multiple lesions). Solitary lesions of the PCP are treated by surgical excision and sometimes local radiotherapy.