Adamantinoma: An Updated Review.

Adamantinoma is a biphasic tumor, with a low potential for malignancy, characterized by clusters of epithelial cells surrounded by a relatively bland spindle-cell osteofibrous component. The aim of the present study was to review the updated data regarding epidemiology; pathogenesis; clinical presentation; radiological, histopathological and ultrastructural findings; and treatment options of adamantinoma. In X-ray, it is usually seen as an eccentric and sometimes central, lobular, lytic lesion with sclerotic margins of overlapping radiolucency, and a characteristic 'soap-bubble' appearance. Magnetic resonance imaging seems to be the most appropriate examination for differential diagnosis between adamantinoma and other skeletal tumors. Histologically, adamantinoma is identified as classic adamantinoma or osteofibrous-like adamantinoma. Classic adamantinoma is classified into four patterns of growth: Basaloid, tubular, spindle cell, and squamous. The preferable treatment of this tumor type is en bloc resection within wide operative margins, which may include suspicious regional lymph nodes, with limb reconstruction and limb salvage.

Outcome of osteofibrous dysplasia-like versus classic adamantinoma of long bones: a single-institution experience.

BACKGROUND: The clinical and molecular characteristics of osteofibrous dysplasia (OFD)-like adamantinoma (AD) differ from those of classic AD. Most reports about OFD-like AD are case reports or small case series. More cases from different centers are still warranted. METHODS: The orthopedic oncology database of our institution was searched to identify patients with AD. The cases of OFD-like and classic AD of the long bones were retrospectively analyzed. Between December 1999 and August 2016, 23 patients were treated for AD, comprising seven with OFD-like AD and 16 with classic AD. The outcomes were compared between AD subtypes. RESULTS: In the OFD-like AD group, four lesions were treated with extensive curettage, while three were treated with wide resection. The median follow-up duration in the OFD-like AD group was 66 months (range 43-131 months). At the end of follow-up, there was only one case of local recurrence (LR) in the OFD-like AD group, giving a LR rate of 14.3% (1/7). No distant metastasis or progression to classic AD was detected in the OFD-like AD group. In the classic AD group, the treatments were below-the-knee amputation in one patient with extensive tibial and fibular lesions, curettage with a bone graft in one patient who was diagnosed with OFD based on a core needle biopsy, hemi-cortical excision and reconstruction in two patients, and segmental resection and reconstruction in 12 patients. At the end of follow-up, there were three cases of LR in the classic AD group, giving a LR rate of 18.8% (3/16); two patients developed lung metastasis after LR and died of the disease at 88 and 126 months after the first surgery in our hospital, respectively. The classic AD group had a metastatic rate of 12.5% (2/16), a final limb salvage rate of 75%, and estimated 5- and 10-year survival rates of 88.9% and 77.1%, respectively. CONCLUSIONS: OFD-like AD has a better outcome than classic AD. For OFD-like AD, extensive curettage is suggested if the tumor extent allows. For classic AD, aggressive resection with wide margins is essential to achieve local control. A long-term follow-up is necessary due to the possibility of late complications.

Osteofibrous dysplasia and adamantinoma.

Osteofibrous dysplasia (OFD) is a rare, benign, fibro-osseous lesion that typically is seen within the cortex of the tibia in children. Adamantinoma (AD) is a rare, low-grade malignant primary bone tumor that occurs most often in the tibia and/or fibula of adolescent persons and young adults; however, it has been reported in other long bones, as well. Immunohistochemical and ultrastructural evidence has shown that the neoplastic cell in AD derives from an epithelial lineage. More recently, published reports have described another clinical entity-differentiated or OFD-like AD-that appears to lie between OFD and AD along a spectrum of disease. Controversy exists as to whether OFD is a precursor lesion to AD or whether OFD may be a residual lesion resulting from a spontaneously regressing AD. Management of OFD varies from observation to surgical intervention, depending on the age of the patient and the extent of the lesion. Management of AD requires surgical resection with wide margins, followed by appropriate reconstruction, to minimize the risk of local recurrence or metastasis.