Open surgical biopsy most accurate method for soft tissue mass diagnosis

Kasraeian S. Clin Orthop Rel Res. Published online: May 29, 2010.

Open surgical biopsy more accurately identified malignancy, established diagnosis and guided appropriate treatment compared with fine-needle aspiration and core biopsy, according to the results of this Level I study.

In their prospective study, Sina Kasraeian, MD, and colleagues at the University of Southern California compared the diagnostic accuracy of three biopsy methods: fine-needle, core and open surgical biopsy.

This study included 57 patients with palpable extremity soft tissue masses. The researchers performed a fine-needle aspiration, then a core biopsy and finally, a surgical biopsy of the same mass.

In soft tissue mass diagnosis, open surgical biopsy was 100% accurate in all three areas: recognizing malignancy, determining accurate diagnosis and directing treatment.

Core biopsy was more accurate than fine-needle biopsy in all three areas. For identifying malignancy, fine-needle aspiration had 79.17% sensitivity, 72.7% specificity, 67.9% positive predictive value and 82.8% negative predictive value. The method had an overall accuracy of 75.4%. In comparison, core biopsy had 79.2% sensitivity, 81.8% specificity, 76% positive predictive value and 84.4% negative predictive value. Core biopsy had an overall accuracy of 80.7%.

Fine-needle biopsy had a 33.3% accuracy rate in establishing the exact diagnosis; core biopsy had a 45.6% rate.

With regard to guiding eventual treatment, fine-needle aspiration was 38.6% accurate and core biopsy was 49.1% accurate.

The authors should be commended on conducting a high level of evidence study on diagnosing palpable primary soft tissue masses.

Percutaneous biopsy for musculoskeletal tumors has a wide variation in accuracy in the existing literature and is controversial in the United States. Kasraeian and colleagues aptly noted that the sensitivity and specificity of percutaneous biopsy is artificially elevated in many previous studies due to the statistical exclusion of indeterminate specimens. They have shown that, despite interpretation by an experienced pathologist, both fine-needle aspiration and core biopsy are not highly efficacious. They showed that these methods would only lead to initiating the correct treatment in a minority of cases at their institution.

As a counter-point, earlier this year we performed a study in which we found fine-needle aspiration to be very reliable and useful in triaging the same patient demographic.

Like many other diagnostic modalities, needle biopsy is highly operator- and interpreter-dependent, and each institution should employ the best test at their disposal. The hazards of musculoskeletal biopsy are well described and the potential morbidity from an erroneous diagnosis is significant. Open incisional biopsy is indeed the gold standard and should never be usurped by other options when the diagnosis is in doubt.

– Vincent Y. Ng, MD
Clinical Instructor
Department of Orthopedics
Ohio State University College of Medicine

Reference:

Ng VY, Thomas K, Crist M, Wakely PE Jr, Mayerson J. Fine needle aspiration for clinical triage of extremity soft tissue masses. Clin Orthop Relat Res. 2010;468(4):1120-1128.