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| Direct scan of slide. The most cellular and collagenous part of the mass extends from the base up to the black outline. Broad collections of collagen bundles, some of which are ossified, arborize from the base. The peripheral surface is mostly eroded and replaced by granulation tissue. There is a broad zone between the black outline and the granulation tissue that is composed of less cellular, moderately vascular connective tissue. Mitoses (none abnormal) are still present. |
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Low power view of the area that is in the black rectangle in the direct scanned view. Metaplastic ossification with focal calcification is present. Woven bone is seen in this field. Lamellar bone was not found. Giant cells are in fibrovascular stroma above and to the left of the ossified collagen. |
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Medium power view of the area in the blue rectangle in the direct scanned view. Numerous giant cells, some of which are osteoclast-like are in fibrovascular stroma. This tumor does not have the lobular architecture seen in the giant cell form of malignant fibrous histiocytoma. |
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High power view of the area in the green rectangle in the direct scanned view. This is from a very cellular area. However, atypia of the type that would be characteristic of an osteosarcoma of soft parts or of an atypical fibroxanthoma is not seen. |
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Medium power view of the area in the red rectangle in the direct scanned view. This broad area is much less cellular than the remainder, but scattered giant cells are seen. The stroma in this picture and the one above is not of the type expected in a dermatofibroma. |
2. Kuo
TT, Chan HL.
Ossifying dermatofibroma with osteoclast-like giant cells.
Am J Dermatopathol 1994 Apr;16(2):193-5.
3. Ramirez-Camacho
R, Vicente J, Garcia Berrocal JR, Ramon y Cajal S.
Fibro-osseous lesions of the external auditory canal.
Laryngoscope. 1999 Mar;109(3):488-91.