A case is reported of a patient with plasmacytoma which assumed different clinicopathological features over seven years. The tumour first presented as a subcutaneous mass which was misdiagnosed as anaplastic carcinoma. Complete response to radiotherapy ensued but recurrence took the form of an intracerebral tumour. Further complete response to "palliative" corticosteroids was followed by osseous lesions three years later, when the diagnosis of plasmacytoma was confirmed. This report illustrates the highly variable clinicopathological presentations of plasmacytoma, including the rare primary cutaneous manifestation.