A case of a giant cell tumor of the chest wall

SESSION TITLE: Signs and Symptoms of Chest Disease SESSION TYPE: Rapid Fire Case Reports PRESENTED ON: 10/09/2023 09:40 am - 10:25 am INTRODUCTION: Giant cell tumors of bone are rare osteolytic neoplasms that tend to occur in young adult patients. They are considered benign but can be locally aggressive. Rarely are there distant metastases to sites such as lung, lymph nodes, soft tissue or brain. These tumors most commonly originate from the metaphyseal-epiphyseal region of long bones of the appendicular skeleton and less commonly occur in the sacrum or spine. Tumors originating in the chest wall are even more unusual. We present the case of a young patient presenting with a breast mass found to have a giant cell tumor of a rib. CASE PRESENTATION: A healthy 19-year-old man presented with several months of progressive dyspnea, and a firm, immobile, and enlarging right breast mass associated with tenderness on palpation. Initial right breast ultrasound showed a heterogeneous solid irregular mass with internal vascularity. A CT scan of the chest demonstrated a right-sided aggressive-appearing chest wall mass that measured 11 cm long in dimension, with extension into the anterior lung, destruction of the fifth rib, and a large pleural effusion. Thoracentesis and ultrasound-guided core needle biopsy of the chest wall mass were performed. No malignant cells were seen on pleural fluid cytology. On histological exam, the biopsy specimen showed a proliferation of multinucleated giant cells, consistent with giant cell tumor of bone. In the context of the imaging findings, the mass was concerning for a grade III giant cell tumor originating from the anterior segment of the fifth rib. There were no other foci of tumor on a PET-CT whole body scan; MRI brain did not show any intracranial metastases. The patient is awaiting a multidisciplinary evaluation for early resection versus neoadjuvant therapy with denosumab. DISCUSSION: Under one percent of giant cell tumors are estimated to arise from the ribs. In case reports that describe a tumor of the anterior ribs, the masses are often initially concerning for breast masses, as was in the case of our patient. Further imaging quickly revealed the destruction of bony structures and soft tissue extension, which broadened the differential to include soft tissue sarcoma. Given the localized nature of giant cell tumors, surgery is the treatment of choice. In the last two decades, increased expression of RANK and RANKL has been identified as a key process in the pathogenesis of giant cell tumors and other osteolytic lesions. Denosumab, an inhibitor of RANKL, is an option for systemic treatment. Given the size of the tumor in our patient, the multidisciplinary treatment team continues to discuss the benefit of denosumab as a neoadjuvant therapy before surgical resection. CONCLUSIONS: Though giant cell tumors are rare, they should be considered in young patients presenting with chest wall masses. REFERENCE #1: Sobti A, Agrawal P, Agarwala S, Agarwal M. Giant Cell Tumor of Bone - An Overview. Arch Bone Jt Surg. 2016;4(1):2. /pmc/articles/PMC4733230/. Accessed March 27, 2023. REFERENCE #2: Basu Mallick A, Chawla SP. Giant Cell Tumor of Bone: An Update. Curr Oncol Rep. 2021;23(5):1-6. doi:10.1007/S11912-021-01047-5/METRICS REFERENCE #3: Hughes EK, James SLJ, Butt S, Davies AM, Saifuddin A. Benign primary tumours of the ribs. Clin Radiol. 2006;61(4):314-322. doi:10.1016/J.CRAD.2005.12.005 DISCLOSURES: No disclosure on file for Nikhil Barot No relevant relationships by Siyuan Cao No disclosure submitted for Vincent Chan No relevant relationships by Michelle Wan