Adamantinoma is a rare tumor with an indolent course that occurs most commonly in the tibia. It is locally aggressive, and local recurrences are described after resection. Pain is the most common symptom. Since the lesion is typically slow growing, the pain can be present for many years before the patient seeks medical attention. Microscopically, adamantinoma consists of islands of epithelial cells in a fibrous stroma. Nuclear atypia is minimal, and mitotic figures are rare. The most common radiographic appearance is that of multiple sharply demarcated radiolucent lesions surrounded by areas of dense, sclerotic bone. This tumor most often affects the tibial diaphysis and produces lytic lesions that can cause fractures. A 31-year-old man presented with a rapidly growing lytic lesion of the distal tibia. On histological examination, many areas of epithelial cells in a fibrous stroma were identified. Diagnosis of adamantinoma was performed. The lesion was treated with en bloc resection and reconstruction with distal tibia allograft and ankle arthrodesis with retrograde nail. At 2-year follow-up, there were no clinical or radiological signs of recurrence of disease.