Ultrastructure of giant cells in tumours induced in golden hamsters by murine sarcoma virus‐harvey

Tumours induced in golden hamsters by murine sarcoma virus‐Harvey were studied in four situations: in subcutaneous tissue, on paws or distal ends of limbs, in muscle and in association with bone destruction. Most of the tumours contained multinucleate giant cells. In subcutaneous tumours, a “filament ous” type of giant cell was seen with long filamentous cell processes and bizarre‐shaped nuclei. Also present was an “interlocking” type which had short cell processes that interlocked with those of surrounding uninuclear cells. The groups of cells formed in this way resembled a granuloma. Degenerating multinucleate sarcolemmal cells were seen at the edge of muscle tumours and “vegetative” muscle cells were also present. A “pleomorphic” type of giant cell was seen in paw, muscle and bone‐eroding tumours. This was a multinucleate cell differentiated to respond to cellular damage caused by tumour infiltration. Groups of cells resembling those seen in granulomas were also present in these tumours.