Giant Cell Tumor of Intermediate Cuneiform Evolving into Aneurysmal Bone Cyst: A Rare Case Report

Introduction: Giant cell tumor (GCT) most commonly involves distal femoral condyles, distal end of radius, proximal tibial plateau, and proximal humerus. GCT is uncommon to occur in small bones of hand and feet. 2% of GCT occur in hand. The incidence of GCT in foot is 1.2–1.8%. Only a few cases have been reported in literature worldwide. GCT is the most common cause of secondary ABC. We report a case of GCT of intermediate cuneiform in a 25-year-old female evolving into aneurysmal bone cyst (ABC). Case Report: A 25-year-old female presented to us with complaints of pain and swelling over the dorsum of right foot for a period of 1 year. On examination, there was a localized ovoid-shaped swelling of 2 by 2 cm over the dorsum of right foot. Radiographs revealed a well-defined osteolytic lesion in the intermediate cuneiform. T2 MRI showed hyper-intense lesion in intermediate cuneiform. The patient was taken up for surgery, and the intermediate cuneiform was excised completely. Removed bone was sent for histopathological examination which confirmed it to be GCT evolving into secondary ABC. The patient was followed for 1 year and had no complaints. The patient was able to weight bear and walk without any difficulty. There was no recurrence of lesion. Conclusion: GCT of the cuneiform evolving into ABC is a very rare presentation. The treatment of choice is excision of the tumor with or without bone grafting. Any osteolytic lesion in the small bones must be evaluated and should be intervened in the early stage. Keywords: Giant cell tumor, osteolytic lesion, surgical resection, intermediate cuneiform.