Tumours arising in skeletal muscle in adults.

A review has been made of 30 cases of tumours arising in skeletal muscle seen over a 21-yr period (1954-74) in the Department of Pathology, Western General Hospital, Edinburgh. There were 17 females and 13 males in the series. The age range was 15 to 88 yr. The commonest site was thigh muscles (18 cases). Seven of the 14 benign tumours were myxomas: the other benign tumours included two solitary myositis ossificans, two haemangiomas and three lipomas. The three tumours which might be considered as being of borderline malignancy were two haemangiopericytomas and one desmoid tumour. There were 13 malignant tumours in the series: five fibrosarcomas, five liposarcomas, two rhabdomyosarcomas and one undifferentiated (pleomorphic) sarcoma. The average length of survival of the nine patients with malignant tumours who have died was only 15 mth. The fibrosarcomas in particular behaved in a highly malignant fashion. These 13 intramuscular sarcomas accounted for approximately 11 per cent, of all mesenchymal (non-lymphoid) sarcomas seen during the period of study.