Radiology Resident Case of the Week
Clinical Sx:
Affected patients complain of local swelling with or without pain.
Etiology/Pathophysiology:
Adamantinoma (Angioblastoma) is an extremely rare, locally aggressive
malignant tumor.
Adamantinomas are slightly more common in men than in women (5:4) with age ranging from 2nd-6th decade. A history of trauma is frequent, and many affected patients describe local swelling with or without pain. The pathogenesis of adamantinoma is epithelial in nature. There is association between adamantinoma containing Ewing's sarcoma&endash;like tumor. Adamantinomas is locally aggressive tumor with the potential to metastasize slowly. 10 year patient survival rate is approximately 10 percent.
It is most common in long bones (97%), especially the tibia (80-85%). Other bones involved in decreasing frequency: the humerus (6%), ulna (4%), femur (3%), fibula (3%), and radius (1%), rarely in the innominate bone, ribs, spine, hand and foot. Within the long bone, it is most common in diaphyseal region. Epiphyseal abnormalities are uncommon. Multiple lesions may represent synchronously or metachronously developing primary tumors or metastases.
In the tibia, adamantinoma usually is localized in the middle third of the bone with variety of pattern. It may appear as a central or eccentric, multilocular, slightly expansile, sharply or poorly delineated osteolytic lesion. Reactive bone maybe seen but periostitis is not common unless there is pathologic fracture.
Pathology:
Microscopically there are epithelial-like and fibrous components.
There are variety of epithelial-like cells inter-mixed within a
fibrous stroma. Four basic forms are found in varying combinations:
basaloid, squamous, spindle, and tubular.
Miscellaneous:
Imaging:
Radiographically, the differentiation of adamantinoma from other
similar disease processes are difficult. Characteristically, they
have eccentric round lytics lesion with sclerotic borders. Often this
is associated with bone expansion and occur in multiples. Findings on
CT and MR imaging the findings are not specific. On MR, the tumor has
low signal intensity in T1 and high signal intensity in T2.
DDX:
Key references:
Diagnosis of Bone and Joint Disorder, 3rd edition, W.B. Saunders
Company
ACR Code:
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