Oral granular cell myoblastoma: an immunohistochemical study

Immunoperoxidase staining for a variety of antigens was performed on 15 cases of granula cell myoblastoma occurring within the oral tissues. All tumours gave intense intracytoplasmic granular staining for a CEA-related antigen with one rabbit antiserum to CEA (Dakopatts) whereas all were negative with a sheep antiserum to CEA (Seward). None of the tumours were positive for lysozyme, alpha 1 antitrypsin to cathepsin B whereas 12 lesions gave a granular reaction for cathepsin D. All granular cells showed a weak reaction for actin in contrast to the strong cytoplasmic staining found in smooth striated muscle and muscle derived tumours.