Diagnostic Concordance Between Biopsy and Surgical Resection in Cartilaginous Tumors

Resumen

Introduction:
The diagnosis and histological grading of cartilaginous tumors remain a major clinical challenge due to their morphological heterogeneity and the frequent overlap between benign and malignant lesions. Core needle biopsy  is the standard approach for preoperative diagnosis; however, its reliability in accurately predicting final tumor grade is still debated, particularly in pelvic or atypical lesions. Diagnostic discrepancies may lead to suboptimal treatment decisions, resulting in overtreatment or insufficient surgical margins.

Objective:
To assess the diagnostic concordance between preoperative biopsy and definitive histopathological findings after surgical resection in cartilaginous tumors of the appendicular and axial skeleton.

Methodology:
We conducted a retrospective, single-center study where we included patients with a diagnosis of cartilaginous tumor confirmed by core needle biopsy between January 2023 and July 2025, who subsequently underwent surgical resection. Clinical, radiological, and histopathological data were collected. The primary outcome was the concordance between the tumor grade on biopsy and on the surgical specimen. Concordance was analyzed globally and stratified by tumor location (appendicular vs pelvic). Kappa statistics were used to assess agreement.

Results:
A total of 63 patients met the inclusion criteria, with a median age of 49 years (range: 18–78); 83% tumors were located in long bones and 17% in the pelvis. Overall concordance between biopsy and surgical histology was 80.6%. In long bones, concordance was 89.7%, while in pelvic tumors it dropped to 65.2%. Discordant cases were due mainly to underestimation of grade in the biopsy. In 16.1% of the patients, the biopsy suggested a low-grade lesion, while surgical histology revealed high-grade features.

Conclusions:
In our institutional experience, core needle biopsy showed good concordance with the final histological grade in cartilaginous tumors of the long bones, but less reliability in pelvic tumors. Radiological features on MRI might provide additional guidance, especially when histological findings are borderline. A multidisciplinary approach remains crucial to minimize diagnostic errors and ensure appropriate surgical planning.