A subcutaneous tumor of a patient with epidermodysplasia verruciformis
was studied by the light microscopy, the electronmicroscopy and
the immunofluorescent test. The tumor cells were histologically pleomorphic
and electronmicroscopically contained varying amounts of cytoplasmic filaments without Z-band formation. The antimyosin serum stained the tumor cells, showing their myogenic origin. No virus or virus-like particles were observed in the tumor. Tumor antigens stainable by the
patient's serum were not detected. Hamsters inoculated with the tumor extract at birth developed no noticeable diseases.</p