[Adamantinoma of the proximal end of the tibia. A case].

Adamantinoma is a rare primary tumour of long bones containing mesenchymatous and epithelial cells. There has been some controversy over the pathogenesis. We observed a localization in the right tibia. A 22-year-old patient from Algeria was seen for spontaneous progressively increasing pain in the upper part of the right tibia. The patient's general health had deteriorated somewhat, with fever. On examination there was ulceration of the skin, costal and pelvic pain and inflammatory right inguinal lymph nodes. Radiography revealed lateral metaphyseal lytic image with interruption of the cortex also seen on magnetic resonance imaging which revealed invasion of the soft tissue and multiple bilateral pulmonary nodules. Bone scintigraphy showed several zones of hyperfixation. The diagnosis of adamantinoma was confirmed by pathology examination of the biopsy specimen. On surgical exeresis, the capsule of the knee joint was found to be involved without invasion of the knee joint. Node dissection showed inguinal and popliteal invasion. Macroscopically, the surgical specimen was a red-whitish osteolytic tumour. Microscopically, the tumour was composed of hyperchromatic epithelial cells in an abondant fibrous stroma. Immunohistochemical studies were negative for vimentine, cytokeratin and factor VIII. Adjuvant chemotherapy was based on a sarcoma protocol. Unfortunately, after two cycles, white cell counts fell sharply and multiple skin nodules appeared together with progression of the bone metastases. The chemotherapy was modified without any therapeutic effect and the patient died in February 1993. An epithelial origin would appear most probable, but at least two groups of adamantinoma can be described: one with typical epithelial differenciation and one overlapping to the differential diagnosis of osteofibrous dysplasia. Although considered as a low grade malignant tumour, we emphasize the aggressive forms with local relapse or metastatic resistance to chemotherapy. Treatment relies on wide surgery and prognosis is generally good. Neither chemotherapy nor radiotherapy has stood the test of time in cases with metastasis.