eMedicine Specialties > Radiology > Musculoskeletal

Adamantinoma: Imaging

Author: Christopher D Smelser, DO, Staff Physician, Department of Radiology, William Beaumont Army Medical Center
Coauthor(s): Robert D Stoffey, DO, Director of Women's Imaging, Department of Radiology, Chief of Mammography Section, William Beaumont Army Medical Center; B Wade Mahaney, MD, Staff Physician, Department of Radiology, William Beaumont Army Medical Center; Sean C Keenan, MD, Staff Physician, Department of Radiology, William Beaumont Army Medical Center; Gary E Simmons, MD, Chief, Department of Radiology, William Beaumont Army Medical Center
Contributor Information and Disclosures

Updated: Mar 19, 2008

Radiography

Findings

In its early stages, an adamantinoma appears as an elongated linear lucency on plain radiographs, and no periosteal reaction is noted in the surrounding bone. In later stages, cortical sclerosis becomes apparent on plain radiographs [see Image 1].

The most common location is in the diaphyseal region of long bones, especially the tibia. A periosteal reaction and fracture are less common late-term sequelae of adamantinomas that can also be depicted on plain radiographs.

The differentiation of adamantinoma from fibrous dysplasia and osteofibrous dysplasia may be difficult by using plain radiographs alone. When questions arise in the diagnosis of the tumor, the histologic and clinical features must be included to narrow the differential diagnosis.

Degree of Confidence

Because of the extremely rare nature of this tumor, the degree of confidence has not been determined.

False Positives/Negatives

False-positive findings include fibrous dysplasia, osteofibrous dysplasia, fibroma (nonossifying or ossifying), bone cyst (aneurysmal or simple), chondrosarcoma, chondromyxoid fibroma, eosinophilic granuloma, and hemangioendothelioma.

Because of the extremely rare nature of this tumor, a list of false-negative findings has not been adequately formulated.

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Computed Tomography

Findings

CT scans often are used to study adamantinomas, but the findings are not specific. CT scans of the lower extremity often reveal a hypoattenuating sclerotic region in the tibial diaphysis [see Image 2].

Degree of Confidence

Degrees of confidence have not been accurately determined because of the rarity of this tumor.

False Positives/Negatives

False-positive findings include fibrous dysplasia, osteofibrous dysplasia, fibroma, bone cyst, and chondromyxoid fibroma.

Magnetic Resonance Imaging

Findings

MRI often is used to image adamantinomas, but the findings are nonspecific. When MRI is used to study adamantinomas, the tumors demonstrate low signal intensity on T1-weighted spin-echo images and high signal intensity on T2-weighted images. Because these appearances are also typical of most tumors, these findings are nonspecific.

Degree of Confidence

Because of the rarity of this tumor, the degree of confidence cannot be accurately determined at this time.

False Positives/Negatives

False-positive findings include fibrous dysplasia, osteofibrous dysplasia, fibroma, bone cyst, and chondrosarcoma.

Related Medscape topics:
Aneurysmal Bone Cyst as a Rare Cause of Spinal Cord Compression in a Young Child

Nuclear Imaging

Findings

Use of nuclear medicine to study adamantinomas is a relatively new undertaking; therefore, few data regarding the tumors have been collected. However, the following findings are believed to correspond to adamantinomous lesions: increased blood flow in the region of the tumor, increased blood pooling, and increased accumulation of technetium-99m methylene diphosphate in the area of the tumor.

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