Soft tissue recurrence in giant cell tumor of bone: risk factors and radiological and histopathological features

Abstract

Objective: Giant cell tumor of the bone (GCTB) is a locally aggressive benign tumor with unpredictable recurrence patterns. While intraosseous recurrences are well-documented, soft tissue recurrence (STR) remains underrecognized. This study aimed to identify risk factors, radiographic features, and histopathological characteristics associated with STR of GCTB. Methods: This retrospective study included 69 patients treated for GCTB between 1996 and 2022. Demographic data, tumor location, surgical method, recurrence history, and adjuvant treatments were extracted from medical records. Radiologic assessments were performed using a picture archiving and communication system, and lesions were graded by Campanacci classification. Histopathological evaluation included H3F3A immunohistochemistry in cases with STRs. Statistical analysis was performed using chi-square, Fisher's exact, and Mann-Whitney U-tests. Results: The initial surgical approach was curettage in 55 patients (79.7%), resection in 14 (20.3%). Recurrence occurred in 24 patients (34.8%), and STR was identified in 7 (10.1%). Most STRs were located near the distal femur. Among these, 4 had prior intraosseous recurrence, and 5 had Campanacci grade 3 lesions. No statistically significant association was found between STR and variables including age, sex, tumor volume, Campanacci grade, tumor location, denosumab, or local adjuvant use. H3F3A analysis was performed in 6 out of 7 patients with STR, and positivity was detected in 3 of them. Pulmonary metastasis was documented in 8 patients overall, including 3 of 7 with STR (42.9%) compared with 5 of 62 without STR (8.1%), representing a significant difference. Conclusion: Soft tissue recurrence in GCTB may occur independently or following intraosseous recurrence and is frequently observed in high-grade lesions. Although not statistically significant, the findings suggest a possible association between tumor aggressiveness and STR. Histological features remain consistent with osseous lesions, but the diagnostic value of H3F3A expression in STRs warrants further investigation. Importantly, STR represents a distinct recurrence pattern and may be associated with an increased risk of pulmonary metastasis, underscoring the need for vigilant long-term follow-up and systematic surveillance.