Alpha-chain disease with localized plasmacytoma of the intestine. Immunoperoxidase study

An ileocaecal tumour in a patient with alpha-chain disease in remission was studied immunohistochemically by a quantitive immunoperoxidase method. The tumour which was histologically shown to be a plasmacytoma consisted of 68% alpha cells and 15% lambda cells; no kappa cells were found. Away from the tumour the pattern of immunoglobulin-producing cells was normal. It is concluded that the abnormal cell causing alpha-chain disease remains inactive and that the patient developed a plasmacytoma from a different cell clone.