Small Musculoskeletal Soft-Tissue Lesions: US-guided Core Needle Biopsy--Comparative Study of Diagnostic Yields...

To determine the effectiveness of ultrasonographically (US) guided core needle biopsy (CNB) for diagnosis of small musculoskeletal soft-tissue lesions by demonstrating the noninferiority of the diagnostic yield with US-guided CNB in lesions measuring 2 cm or smaller to that for lesions larger than 2 cm.

This retrospective study was institutional review board approved, and the requirement to obtain informed consent was waived. Five hundred US-guided CNBs performed for diagnosis of musculoskeletal soft-tissue lesions were included. Results of US-guided CNBs were divided into four categories, and the diagnostic yields were calculated on the basis of lesion size. A one-sided 97.5% confidence interval was calculated to determine the mean difference in diagnostic yields to test for noninferiority. In addition, the diagnostic yield with US-guided CNBs for lesions 1 cm or smaller was compared with that for lesions larger than 1 cm.

A total of 500 technically successful US-guided CNBs in 494 patients with musculoskeletal soft-tissue lesions who underwent subsequent surgical excision or at least 6 months of follow-up were included. The diagnostic yields with US-guided CNB were 87% for lesions larger than 2 cm and 88% for lesions 2 cm or smaller. The lower bound of the confidence interval was -0.07, thus the noninferiority of the diagnostic yield with CNB for lesions 2 cm or smaller to that for lesions larger than 2 cm was shown. On the other hand, the diagnostic yield with US-guided CNB for lesions 1 cm or smaller was inferior to that for lesions larger than 1 cm.

US-guided CNB of musculoskeletal soft-tissue lesions is effective for diagnosis and decision making, even in lesions measuring 2 cm or smaller. However, when a lesion is 1 cm or smaller, US-guided CNB is more frequently insufficient for histopathologic diagnosis.