Conversion to Complete, Parenchyma-Sparing Resection after Prolonged Denosumab for Bilateral Multifocal Pulmonary Metastases from Giant Cell Tumor of Bone: A Case Report

TL;DR

A woman with lung metastases from a bone tumor achieved long-term remission after denosumab treatment followed by precise lung surgery.

Contribution

Demonstrates a surgery-forward strategy using denosumab to enable parenchyma-sparing resection in multifocal pulmonary GCTB.

Findings

Denosumab treatment over 2.5 years led to shrinkage and calcification of lung metastases.

Staged thoracoscopic resections achieved complete macroscopic clearance with negative margins.

The patient remains recurrence-free 7 years and 5 months post-surgery.

Abstract

Giant cell tumor of bone (GCTB) rarely metastasizes, but pulmonary lesions pose therapeutic challenges. We report a woman in her 30s who developed multiple bilateral lung nodules 3.5 years after distal ulna GCTB resection and local recurrences. Denosumab 120 mg every 4 weeks was given for 2.5 years, producing shrinkage, calcification, and stability. Staged, palpation-guided thoracoscopic wedge resections (8 left, 5 right) achieved complete macroscopic clearance with negative margins. Histology showed spindle-cell proliferation with woven bone and depletion of giant cells; H3.3 G34W immunostaining confirmed metastatic GCTB. She remains recurrence-free 7 years and 5 months after metastasectomy. Denosumab displayed site-specific surgical implications—unfavorable at the primary bone site due to peritumoral sclerosis, yet advantageous in the lung where it clarifies margins and enables parenchyma-sparing R0 resection. A surgery-forward strategy that uses time-limited denosumab as a bridge to meticulous thoracoscopic metastasectomy may secure durable control in multifocal pulmonary GCTB.

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