Solitary Extraskeletal Giant Osteochondroma of the Ankle in a Four-Year-Old Boy

Solitary extraskeletal osteochondromas are rare benign lesions usually located close to a joint and are characterized by the absence of continuity with the adjacent bone. They are usually found in the hand and feet and are extremely rarely reported in the growing skeleton. In this paper, we describe a four-year-old boy who presented with a solitary calcified tumor in the posterior part of his ankle. We performed a detailed evaluation using plain X-rays, a CT scan, and an MRI, which revealed a well-demarcated calcified tumor that had the characteristics of an osteochondroma but without any continuity with the bones of the ankle joint. The lesion was treated surgically with the excision of a giant osteochondral lesion. Pathological examination revealed mature cartilage at the periphery with cancellous bone in the central part. Thus, we present the clinical and laboratory investigation of a solitary extraskeletal osteochondroma in the ankle of a four-year-old boy, which is an extremely rare case.