Juvenile intracortical adamantinoma of the tibia with predominant osteofibrous dysplasia-like features.

In view of the still disputed relationship between adult adamantinoma and osteofibrous dysplasia in children, a unique case of adamantinoma, indicating a direct relationship between the two lesions, is presented with a review of the literature. The patient was a six-year-old boy who complained of pain and swelling in the left lower leg. Roentgenographs showed a loculate osteolysis surrounded by sclerosis within the cortex of the tibial shaft that would be typical of osteofibrous dysplasia. Although an osteofibrous-dysplastic component predominated histologically, some small islands of epithelial cells were scattered throughout the lesion. Immunohistochemically, the tumor cells of these epithelial islands gave a constant positive reaction for cytokeratin as well as vimentin, while the stromal cells in the osteofibrous dysplasia-like lesion were positive for vimentin only. This type of lesion is recorded in the Bone Tumor Registry of Westphalia at a rate of 8.3% for osteofibrous dysplasia, and of 25% for adamantinoma. A review of the literature, yielding reports with remarkable uniformity on 14 cases beyond the present one, suggests the existence of a separate clinicopathologic entity to be called juvenile intracortical adamantinoma with predominant osteofibrous dysplasia-like features, and which might be a regressing form of adamantinoma specific in childhood.