Value of Tru-cut biopsy in the diagnosis of soft tissue tumours.

The light microscopic appearances of Tru-cut needle biopsies from 50 consecutive soft tissue tumours were assessed by three pathologists and compared with the definitive histological diagnosis. Forty-four patients had soft tissue sarcomas and six had benign soft tissue lesions. A correct predictive diagnosis of sarcoma was made on 87-98 per cent of adequate Tru-cut specimens, the accuracy varying between pathologists. Three sources of diagnostic error were recognized: false positive cores (8 per cent), false negative cores (8 per cent), and cores inadequate for diagnosis (16 per cent). The major source of confusion related to difficulties in differentiating infiltrating fibromatosis from malignant fibrous histiocytoma. The high sensitivity of Tru-cut needle biopsy suggests that it could be a valuable aid in the diagnosis of clinically suspected soft tissue sarcomas.