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| IMAGE QUIZ ARCHIVE | ||||||
| Image Quiz | ||
| Neck Pain in a Forty-Six-Year-Old Woman1 (continued) | ||
 Fig. 3-A |
Fig. 3-A Photomicrograph of a specimen from the facet lesion shows a cellular focus composed of small mononuclear cells, with an aggregate of multinucleated osteoclast-type cells seen in the right side of the field, juxtaposed to a sheet of pale foamy histiocytes (hematoxylin and eosin, ×150). For larger view, click on image |
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 Fig. 3-B |
Fig. 3-B Photomicrograph of cellular region shows mononuclear cells with round to oval nuclei. Most of the cells have a pale vesiculated cytoplasm. Two multinucleated osteoclast-type giant cells are also present (hematoxylin and eosin, ×600). For larger view, click on image |
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| The curettage material consisted of multiple fragments of tan-brown and yellow to tan-gray tissue ranging from 0.5 to 2.0 cm in size. Histologically, the tissue was composed mostly of nodules and sheets of bland, foamy, lipid-laden histiocytes as well as a diffuse proliferation of smaller, histocyte-like cells having a scant, nonfoamy cytoplasm and bland nuclei, some of which were clefted (Figs. 3-A and 3-B). Scattered osteoclast-like giant cells were present throughout the tissue. In some areas, there was extensive serpentine-like hyaline fibrosis that focally replaced the lesional cells. Mitotic activity was not evident. Intracellular and extracellular hemosiderin pigment was apparent in the routine hematoxylin and eosin-stained sections. No chondroid, aneurysmal-bone-cyst-like areas, or inflammatory cells were present, and there was no evidence of a synovial lining. Immunohistochemical staining showed the component cells to be nonreactive for S-100 protein and CD1a. Foam cells, smaller histiocyte-like cells, and giant cells were strongly and diffusely reactive for CD68. Staining for iron showed focal regions that contained abundant iron pigment. The histological diagnosis was pigmented villonodular synovitis. | ||
| Discussion | ||
| Pigmented villonodular synovitis of the spine is rare, with a cervical location even more unusual. | ||
| The plain radiographic appearance of spinal pigmented villonodular synovitis is variable, but it usually shows destruction of the posterior elements of the vertebral body. The radiographic differential diagnosis includes aneurysmal bone cyst, granulomatous infection, synovial chondromatosis, rheumatoid arthritis, and osteoblastoma. Occasionally, a concomitant soft-tissue mass is present; however, any extradural mass-effect is rarely appreciated on plain radiographs. The features seen on computed tomography and magnetic resonance imaging in our patient suggested a slow-growing process centered in the synovial joint between the right lateral masses of the first and second cervical vertebrae, with erosion of the adjacent second cervical vertebral body. | ||
| Pigmented villonodular synovitis of the spine typically arises from the synovial lining of a facet joint. When it is located near a degenerative joint surface, a synovial cyst must be considered in the differential diagnosis; however, pigmented villonodular synovitis may sometimes be differentiated from a synovial cyst on magnetic resonance imaging scans by the localization of areas of attenuation secondary to hemosiderin deposits. | ||
| The heterogeneous signal of the mass on the T2-weighted magnetic resonance images prompted the reevaluation of our patient. The amount of hemosiderin in the lesion affects its appearance on T2-weighted images. When a large amount of hemosiderin is present, the tumor contains characteristic areas of very low signal intensity on all pulse sequences. However, when there is only a moderate amount of hemosiderin, as in our patient, the intensity of the T2-weighted signal is lower than that usually seen in most soft-tissue neoplasms, but it remains hyperintense compared with that in muscle. | ||
| Reference | ||
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