Faculty Bibliography

An immunohistochemical study of six giant cell tumors of bone and eight related lesions (aneurysmal bone cyst, fibrous histiocytoma, and giant cell tumor of tendon sheath) was performed using a panel of monoclonal antibodies directed to the Ia and monocyte-macrophage lineage antigens. In all types of lesion, osteoclastlike multinucleate giant cells were negative for both types of antigen, but a proportion of mononuclear cells gave positive reactions. While the possibility that these cells are reactive cannot be excluded, in giant cell tumor and malignant fibrous histiocytoma, their frequency and their morphologic similarity to the rest of the tissue suggest that they may be an intrinsic part of the neoplasm. This finding is consistent with the presumed fibrohistiocytic nature of these tumors.

The first reported case of a periosteal ganglion to be documented by computerized tomography is presented. The lesion was located on the shaft of the tibia and was unrelated to ligamentous and joint structures. A review of the literature reveals that the most common site for this lesion is the upper leg, as noted in our case; for that reason, periosteal ganglion should be included in the differential diagnosis of any soft tissue lesion in this location. CT may be more useful than plain films to demonstrate periosteal ganglion when cortical erosion is absent.

Of 30 patients with synovial chondromatosis, nine had prominent pressure defects at the articular margins of the hip and shoulder. Erosions of bone may be extensive, and the patient can be at risk for developing a pathologic fracture. Synovial chondromatosis should be considered in the differential diagnosis of lesions causing erosions of the articular ends of the bones; it is not as uncommon as has been previously suggested.

We performed an immunohistochemical study of 24 giant-cell tumors of bone and 30 other lesions (fibrous histiocytoma, nonossifying fibroma, and giant-cell tumor of the tendon sheath) using lysozyme and alpha 1-antitrypsin as markers for histiocytic cells. The presence of histiocytic cells in giant-cell tumors of bone is confirmed by the finding of a positive reaction for alpha 1-antitrypsin in both multinucleate giant cells and mononuclear stromal cells in some cases. It is not clear whether the positive cells are to be regarded as neoplastic or reactive and alpha 1-antitrypsin is not considered as a diagnostically useful marker for giant-cell tumor of bone. In malignant fibrous histiocytoma, too, histiocytic cells could be identified by their positive reaction for alpha 1-antitrypsin; some of these cells had the morphologic features of tumor cells. Cells with a positive reaction for lysozyme were rarely found, except in giant-cell tumors of the tendon sheath.

A primary neoplasm of the proximal humerus in a 68-year-old woman was unique histologically in that it contained both malignant cartilaginous and squamous cell components. The epithelial differentiation was confirmed by the demonstration of keratin by immunohistochemical techniques and of basement membrane, tonofilaments, and well-formed desmosomes by electron microscopy. The patient died 3 1/2 years after the onset of symptoms, without clinical evidence of either a primary tumor elsewhere or metastasis. The differential diagnosis from other bone tumors with epithelial differentiation, such as adamantinoma and "primitive multipotential primary sarcoma," is discussed. This is a rare primary neoplasm of bone of unknown histogenesis. Intermutability or metaplasia between mesenchymal and epithelial tissues is a possibility. The tumor probably originated from multipotential stem cells with the ability to undergo biphasic or dual differentiation toward mesenchymal and epithelial elements.

With increasing use of chemonucleolysis, interest and use of discography is at an all-time high. Various reports in past years have disagreed on the safety and efficacy of intradiscal injections of contrast mediums. This experimental study was devised to determine the effects of discography on the gross and histologic appearance of the lumbar intervertebral disc. Through a laparotomy approach, five lumbar discs in ten dogs were exposed. In each dog, one disc served as a control, another punctured with a needle, and the others injected with metrizamide, hypaque, or saline, At 2, 4, 6, 8, and 10 weeks postoperative, two dogs were killed at each time interval. Examination of the discs revealed no gross differences between any of the groups. The normal gross architecture of the concentric annulus and gelatinous nucleus was maintained in all specimens. This study found no evidence that discography results in gross or histologic damage to the intervertebral disc. It does not appear that discography will predispose a normal intervertebral disc to herniate. Discography alone appears to be a safe diagnostic procedure with no experimental evidence of any untoward gross or histologic effects.

The coexistence of mixed sclerosing bone dysplasia and dysplasia epiphysealis hemimelica is a rare anomaly. This combination of abnormalities has not been previously reported. The clinical, radiographic, and pathologic features of this condition are discussed and the methods of treatment of articular complications are reviewed

Eight cases of fibrous dysplasia were evaluated by electron microscopy and the findings were correlated with the light microscopy. Fibroblasts and myofibroblasts were the cells seen in the fibrous component. The osseous component consisted of immature woven bone trabeculae lined by abnormal osteoblasts with a fibroblastlike appearance. The cartilaginous component resembled hyaline cartilage. The process of mineralization of both osseous and cartilaginous tissues appeared similar to normal bone and cartilage. In fibrous dysplasia there is a slow turnover of bone, and this correlates well with the flattened shape of the bone-lining cells. When compared with normal ossification, the process of bone formation appears to be arrested after an early stage resembling membranous ossification. It is possible that the abnormal osteoblastic maturation of the bone-forming mesenchyme is one of the most important alterations of this condition