Admantinoma is a rare primary tumour of long bones was so named because of its resemblance to ameloblastoma (adamantinoma) of the mandible.
Localization
The lesion has a strong predilection for the tibia in about 90 percent of cases. It has been found in other long bones, such as the ulna, humerus, femur,fibula, and capitate.
Multifocal involvement of the tibia and fibula has been reported; in one patients in addition to the tibia and fibula the femur was also affected.
Age and Sex Predilection
Adamantinoma is a tumor of adult life with a median age occurrence of the mid-thirties. It occurs with equal frequency in males and female. However, occurrence in adolescence and, rarely, in childhood has been reported.
Clinical Features
The presenting complaint is local pain with an insidious onset, developing over a period of several months to years. There may be a history of trauma. On palpation there is localized hard swelling and tenderness of a varying degree.
Radiographs and Imaging
The lesion is commonly located in the middle third of the diaphysis of a long bone; it may, however, extend to either end to involve the metaphyses. On rare occasions, with aggressive adamantinomas, the epiphysis may be affected. Primary location in the epiphysis has not been reported.
The radiographic appearance depends on the site of origin of the tumor-whether intracortical or intramedullary.
The internal radiographic pattern may be one of several types:
- A solitary area of irregular rarefaction in the cortex, which is expanded on its outer surface
- Bubbled locules in which multiple areas of expanded cortical rarefaction are separated by delicate step
- Sawtoothed lysis caused by external subperiosteal bone erosion
- Fibrosclerosis, which consists of numerous small areas of cortical rarefaction with sclerotic margins.
There is little if any periosteal rarefaction. In intracortical lesions there may be marginal buttressing.
In the intramedullary types of admantinoma the radiographic pattern may be circumscribed lytic, multilocular expansile, or satellite sclerotic; on rare occasions intramedullary lesions may resemble reticulated honeycomb or be frankly destructive.
Scintigraphy with technetium-99m will show increased uptake in the lesional area. The periphery of the area of increased uptake on the scan corresponds to the rim of the reactive zone about the lesion.
Computed tomography will clearly delineate the area of bone destruction-cortical or intramedullary, the nature of the reactive areas in the transition zone, and whether there is soft tissue extension.
Arteriography shows marked increased vascularity with abnormal vascular channels in the area of bone destruction.
Differential Diagnosis
Multiple areas of radiolucency with an admixture of sclerosis of the diaphyseal and metaphyseal regions of a long bone may be seen in a number of other bone tumors.
Benign lesions to consider in the differential diagnosis are
- Fibrous dysplasia
- Nonossifying fibroma
- Desmoplastic fibroma
- Osteoblastoma
- Osteofibrous dysplasia
- Periosteal fibroma
- Aneurismal bone cyst.
- Brown tumor in hyperparathyroidism should be ruled out.
- Haemophilic pseudotumor may give a similar radiographic appearance.
- Hydatid bone cyst should be ruled out.
- Lytic phase of Paget’s disease may be mistaken for adamantinoma in the radiograph.
Malignant lesions to consider in the differential diagnosis
- Myosarcoma
- Fibrosarcoma, reticulum-cell sarcoma, osteogenic sarcoma, and metastatic carcinoma.
Treatment
Marginal excision often results in recurrence.
It is recommended that the tumor be excised by a wide surgical margin.
In the tibia, if the tumor has penetrated the medullary canal, a full segmental resection is performed in order to achieve a wide surgical margin; an allograft is utilized for reconstruction.
If the tumor is well marginated and intracortical, involving the anterior cortex only, an attempt may be made to preserve the posterior cortex to facilitate reconstruction; it should, however, be understood that it carries a greater risk of recurrence.
When adamantinoma is aggressive, extending into soft tissues, or when attempted segmental resection has failed and there is aggressive recurrence, a below-knee amputation or knee disarticulation is performed.
If pulmonary metastases develop they are removed by wide excision.
Popularity: 1% [?]
Related posts:
Join Discussions