PMC4898178_01
41-year-old male with periosteal osteoblastoma. An AP (top) and lateral (above) radiograph of the distal left femur demonstrate a lytic lesion with aggressive periosteal reaction.
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The mass was shaped like a dome and showed amorphous osteoid-type mineralization and aggressive periosteal reaction (Fig. 1).
41-year-old male with periosteal osteoblastoma. An axial CT shows cortical destruction with central osteoid mineralization. Solid periosteal reaction and focal area of aggressive periosteal reaction of sunburst pattern are also present.
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CT of the lesion showed that its epicenter was at the cortical surface, with a small mass projecting into the soft tissues and a lytic component that appeared to penetrating the cortex and extending into the medullary space (Fig. 2).
41-year-old male with periosteal osteoblastoma. A sagittal reformatted CT also shows cortical destruction with central osteoid mineralization. Solid periosteal reaction and focal area of aggressive periosteal reaction of sunburst pattern are also present.
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Amorphous mineralization was present within the lesion, and aggressive periosteal reaction with sunburst morphology was present (Fig. 3).
41-year-old male with periosteal osteoblastoma. Sagittal T1-weighted MR image demonstrates T1 hyperintensity and cortical disruption.
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MRI showed the lesion straddling the cortex, with most of the tumor volume on the surface of the bone (Fig. 4).
41-year-old male with periosteal osteoblastoma. Axial (top), coronal (middle), and sagittal (above) long TR with FS images show perilesional edema. The lesion is mixed high and low in signal intensity.
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T2-weighted sequences, with extensive surrounding marrow, periosteal, and soft-tissue edema (Fig. 5). The lesion was hot on radionuclide bone scan (Fig. 6). The radiologic impression was that of periosteal osteosarcoma.
41-year-old male with periosteal osteoblastoma. Anterior and posterior whole-body bone scans show increased uptake in the distal femur lesion.
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T2-weighted sequences, with extensive surrounding marrow, periosteal, and soft-tissue edema (Fig. 5). The lesion was hot on radionuclide bone scan (Fig. 6). The radiologic impression was that of periosteal osteosarcoma.
41-year-old male with periosteal osteoblastoma. Bone forming lesion of the surface of the cortex (left) with no invasion of the underlying cortex (right).
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Further evaluation of the frozen and permanent histological sections demonstrated similar trabecular bone formation lined by plump osteoblasts and occasional osteoclasts with a richly vascular stroma typical of osteoblastoma (Fig.7).
41-year-old male with periosteal osteoblastoma. Irregular and variably mineralized small trabeculae of woven bone lined by osteoblasts and occasional osteoclasts. A fibrovascular stroma and osteoblasts are seen in the intertrabecular space. A few of the osteoblasts are enlarged with abundant cytoplasm (epithelioid osteoblasts).
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Importantly, there was no evidence of invasion of the underlying bone, further helping to exclude osteosarcoma (Fig. 8).