Effects on histomorphology of Giant cell tumor due to advancement in the treatment modalities – An insight from a tertiary care centre

Abstract

Introduction: Giant cell tumor (GCT) of bone is a neoplasm which is characterized by presence of multinucleated osteoclasts type giant cells embedded in a mononuclear stromal cell. Surgery is the primary treatment for GCT of bone, but recurrence remains the concern. In this article, we discuss the morphological changes in histopathology by different modalities of treatment of GCT. Material and methods: Histologically proven fifteen cases of GCT of bone were studied over a period of one year in 2023 from the Department of Pathology, Bharati Vidyapeeth Medical College, Pune, Maharashtra, India. The data was collected on various relevant clinical aspects and evaluated. Discussion: GCT of the bone is a locally aggressive osteolytic neoplasm that involves the epiphysis of long bones. GCT affects individuals in the second or fourth decade. The tumour has an equal sex predilection. It is the outcome of interaction between RANK (Receptor activator of nuclear factor kappa B) and RANKL (Receptor activator of nuclear factor kappa-B ligand) which is expressed on the osteoclastic giant cells and mononuclear cells, respectively. In recent years, development of targeted therapy in GCT has changed the pathway for treatment. Denosumab is a monoclonal antibody that targets RANKL, thus resulting in effects on histomorphology which are deceptive to the pathologist. Conclusion: GCT is characterized by a proliferation of mononuclear stromal cells and the presence of many multi- nucleated giant cells with homogenous distribution. Various treatment modalities with recent advances in targeted therapy is now changing the landscape for treatment. It is necessary that the pathologist should be aware of these targeted therapy related changes on morphology to prevent diagnostic pitfalls as it poses therapeutic and prognostic implications.

Keywords:  1) Giant cell tumor 2) RANKL 3) Denosumab