Adamantinoma of tibia presenting as a benign bone cyst

ABSTRACT

Adamantinoma (AD) is a very rare, low-grade, malignant bone tumour that accounts for approximately 0.4% of all primary bone tumours. In 1913, Fischer named the lesion "adamantinoma" because it resembles AD of the jaw. In Contrast to those found in the jaw, adamantinomas of the long bones metastasize in 20% of the cases, usually to the lungs and nearby lymph nodes. The tumour primarily occurs in patients aged between 20-40 years and 85-90% of cases, the tibia is affected [15]. Diagnosis of adamantinoma is clinically complicated except for typical cases because it is quite similar to other benign bone lesions, such as fibrous dysplasia (FD) and osteofibro dysplasia (OFD) of long bones with respect to radiological and pathological findings. The typical location of adamantinoma is the intracortical areal of the diaphysis. Plain film have shown a well circumscribed, cortical, multilobulated osteolytic lesion with intralesional opacities, septation and peripheral sclerosis. These findings imply the lesions' nature of slow growth [6,7]. Immunohistochemical and ultrastructural evidence have shown that the neoplastic cells in AD derives from epithelial lineage. Recent reports have described another clinical entity-differentiated or OFD-like AD that appears between OFD and AD along a spectrum of disease. Features resembling other lesions such as OFD or FD may lead to misdiagnosis and result in inadequate treatment of this tumour[9].