ADAMANTINOMA OF THE UPPER PART OF THE TIB IA - A CASE-REPORT

Adamantinoma is a rare primary tumour of long bones containing mesench ymatous and epithelial cells. There has been some controversy over the pathogenesis. We observed a localization in the right tibia. A 22-yea r-old patient from Algeria was seen for spontaneous progressively incr easing pain in the upper part of the right tibia. The patient's genera l health had deteriorated somewhat, with fever. On examination there w as ulceration of the skin, costal and pelvic pain and inflammatory rig ht inguinal lymph nodes. Radiography revealed lateral metaphyseal lyti c image with interruption of the cortex also seen on magnetic resonanc e imaging which revealed invasion of the soft tissue and multiple bila teral pulmonary nodules. Bone scintigraphy showed several zones of hyp erfixation. The diagnosis of adamantinoma was confirmed by pathology e xamination of the biopsy specimen. On surgical exeresis, the capsule o f the knee joint was found to be involved without invasion of the knee joint. Node dissection showed inguinal and popliteal invasion. Macros copically, 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, cytokeratine and factor VIII. Adjuvant chemoth erapy was based on a sarcoma protocol. Unfortunately, after two cycles , white cell counts fell sharply and multiple skin nodules appeared to gether with progression of the bone metastases. The chemotherapy was m odified without any therapeutic effect and the patient died in Februar y 1993. An epithelial origin would appear most probable, but at least two groups of adamantinoma ran be described: one with typical epitheli al differenciation and one overlapping to the differential diagnosis o f osteofibrous dysplasia. Although considered as a low grade malignant tumour, we emphasize the aggressive forms with local relapse or metas tatic resistance to chemotherapy. Treatment relies on nide surgery and prognosis is generally good. Neither chemotherapy nor radiotherapy ha s stood the test of time in cases with metastasis.