Young Female with Calcaneal Chondroblastoma & Secondary Aneurysmal Bone Cyst: Case Report.

Introduction: Calcaneal chondroblastoma with secondary aneurysmal bone cyst is an exceptionally rare occurrence with few cases published in the literature. Differentiating primary aneurysmal bone cyst from secondary aneurysmal bone cyst in the setting of chondroblastoma is important as it has implications for orthopedic management and follow up. This case illustrates the transition from an initial impression of an aneurysmal bone cyst to the definitive diagnosis of an underlying chondroblastoma, leading to appropriate treatment and a positive outcome. Case Report: A 20-year-old Hispanic female presented with a lytic lesion in the left calcaneus, initially suspected to be an aneurysmal bone cyst. Histopathological examination confirmed chondroblastoma with secondary ABC. The patient underwent extended curettage with bone grafting, supplemented by adjuvant therapy using argon gas and hydrogen peroxide. Postoperatively the patient had a good outcome with no evidence for recurrence at time of last exam. Conclusion: Chondroblastoma with secondary aneurysmal bone cyst in the calcaneus is an exceptionally rare event that requires a comprehensive diagnostic and therapeutic approach. Early recognition and appropriate surgical management are crucial to achieving favorable outcomes and minimizing the risk of recurrence. Continued research and case documentation are necessary to further understand the optimal management strategies for this unique clinical presentation.