Small Musculoskeletal Soft-Tissue Lesions: US-guided Core Needle Biopsy—Comparative Study of Diagnostic Yields according to Lesion Size

Abstract

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.