Abstract

Background: Non-diagnostic (ND) musculoskeletal biopsies of soft tissue lesions can increase patient anxiety and delay definitive diagnosis and treatment. It is thought the specific histotype of the lesion may influence accuracy of the biopsy. This study aims to assess if ND musculoskeletal biopsies are more likely to represent benign or malignant conditions, and whether specific diseases are more likely to result in a non-diagnostic biopsy result.

Material and methods: This was a retrospective study of patients in a regional bone and soft tissue tumour unit between March 2010 and September 2019. Biopsies were done using clinical guidance by the surgical team (performed using clinical landmarks instead of image-guidance), or image-guidance (ultrasound or CT) by a musculoskeletal radiologist. Non-diagnostic biopsies were identified, and the final diagnosis was categorised as benign or malignant; the final tissue diagnosis was recorded.

Results: A total of 1,561 cases underwent biopsy of soft tissue lesions, mean age 57. Further biopsies were done in 30 cases (2%). Benign diagnoses were more commonly identified in non-diagnostic biopsies (23 cases (77%)). Vascularised, cystic and myxoid lesions appeared most frequently, and haematomas/ arteriovenous malformation were significantly more likely to need two biopsies. Over half (16 cases) of non-diagnostic biopsies were done without imageguidance.

Conclusion: This study shows that, for non-diagnostic musculoskeletal biopsies, a benign diagnosis is more common than malignant. The most frequent lesions with non-diagnostic biopsies were mainly myxoid, cystic and vascular lesions, and in these cases, we feel image-guidance may improve accuracy.