Abstract
Adamantinoma is a primary low-grade, malignant bone tumor that is predominantly located in the mid-portion of the tibia. The aetiology of the tumor is still a matter of debate. Histologically, classic adamantinoma is a biphasic tumor characterized by epithelial and osteofibrous components that may be intermingled with each other in various proportions and differentiating patterns.
We report here a particular morphologic variant of adamantinoma characterised by the loss of classic epithelial differentiation. A 17 year-old teenager presented with a long history of a tumor in the left leg. Explorations revealed an osteolytic lesion of the middle shaft of the left tibia with a huge mass invading soft tissues. An intra medullar bone lesion with benign appearance was observed in the right tibia. CT of the chest revealed lung metastases. Histologically, we observed in the left side a pattern of spinde-celled high grade sarcoma without any evident differentiation. Spindle-shaped tumor cells express cytokeratins and vimentin. Ultrasturctural study showed tonofibrils and desmosomes and was helpful to recognize the epithelial nature of the tumour. The diagnosis of dedifferentiated adamantinoma was retained. In the right tibia biopsy revealed fibrous dysplasia. Amputation above the knee was performed followed by chemotherapy. One year later, the patient is still alive with multiple lung metastases.
In our study, we discussed the clinico-pathologic features of this particular pattern of adamantinoma as well as its association with fiobrous dysplasia in this case. A review of literature was done.
Correspondence should be addressed to Professor Stefan Bielack, Olgahospital, Klinikum Stuttgart, Bismarkstrasse 8, D-70176 Stuttgart, Germany. Email: s.bielack@klinikum_stuttgart.de
