Faculty Bibliography

This study was undertaken to explain the increased scintigraphic activity of some bone islands by correlating the clinical, radiographic, scintigraphic, and histopathologic findings. The material for the study consisted of six patients with bone islands who had undergone histopathologic examinations of the lesions. Based on histopathologic-radiologic correlations, we postulate that the osteoblastic activity of a bone island makes it appear 'hot' on scintigraphy, although other factors such as the size of the lesion may play some role in this phenomenon. In addition, we tried to find a logical algorithm for the radiologic evaluation and management of sclerotic lesions that look like bone islands but exhibit increased uptake of radiopharmaceuticals on bone scan examination. We emphasize that the morphology of the lesion, as demonstrated on the radiologic examination, rather than its degree of activity on the bone scan is a guide to the correct diagnosis

The ultrastructure of two cases of brown tumor of hyperparathyroidism is described. The most frequent cells found are multinucleated giant cells and fibroblasts. The giant cells have ultrastructural features similar to osteoclasts such as numerous mitochondria, dilated rough endoplasmic reticulum, and short filopodia. However, the ruffled borders typical of osteoclasts are not seen. In this manner, the giant cells of brown tumor are inactive osteoclasts. The fibroblasts show myofibroblastic differentiation. We think that brown tumor represents a reparative cellular process similar to giant cell reparative granuloma of bone.

Periosteal chondroma is a slow-growing benign cartilaginous tumor of limited size arising within or under the periosteum, which, through constant pressure, induces cortical erosion and periosteal reaction. Ten new cases of periosteal chondroma are reported. All were treated by marginal or intralesional excision. No local recurrence was seen following this treatment. These patients demonstrated the clinical, roentgenographic, and pathologic features of this benign entity, which aid diagnosis, thereby avoiding overtreatment.

A case of a giant cell tumor of the right proximal femur that developed malignant change following surgical treatment ("secondary" malignant giant cell tumor) is presented. The patient had a cystic lesion that was initially interpreted as an aneurysmal bone cyst. A local recurrence six months later demonstrated the histological features of typical giant cell tumor. A further recurrence 22 months after the original treatment showed histological malignancy. Death was due to massive local recurrence and to extension of the malignancy to the pleura.

Macrodactyly is an unusual congenital anomaly in which there is hamartomatous proliferation of the soft tissue of the affected digit. It is usually present at birth or recognized during adolescence. Eleven cases are presented. All showed abnormal accumulation of adipose tissue in the affected digits. In five cases, prominent endoneural and perineural fibrosis was noted. Two cases also demonstrated focal neural and vascular proliferation. This is an unusual finding in macrodactyly and may be a part of the abnormal hamartomatous proliferation that is observed in this condition. None of the patients had clinical evidence of neurofibromatosis. One patient had the Proteus syndrome.

The presence and distribution of type II collagen was studied in 36 cartilage and cartilage-related tumors, including five osteosarcomas and one chordoma. A monoclonal antibody prepared from chicken type II collagen was used with paraffin sections, employing the ABC (avidin biotinylated horseradish peroxidase complex) peroxidase technique. Fetal cartilage and fracture callus were used as control materials. Type II collagen was present in the matrix of all the cartilage tumors. The reaction was strongest in areas of well-differentiated cartilage and weakest in the poorly differentiated tissue of high-grade chondrosarcomas. Areas of mineralization or ossification, and areas of eosinophilic, fibrous, or degenerated cartilage gave a negative reaction.

A report of two patients in which a soft tissue mass, initially regarded as a malignant tumor, was shown to be the result of calcium pyrophosphate deposition disease. The first case, a woman aged 71 years, presented with a mass involving the right fifth finger. In the second case, also a woman aged 71 years, the lesion involved the tissues adjacent to the right hip. Each lesion consisted of a mass of highly cellular tissue containing deposits of calcium pyrophosphate dihydrate crystals. The clinical, radiological, and pathological features of the two cases are compared with those of seven similar cases reported in the literature.

A malignant round cell tumor primary in bone is reported in a young girl, showing histologically rosette formation and pseudoalveolar spaces. Vimentin, NSE, and S-100 were positive. Electron microscopy demonstrated abundant glycogen and neural features such as cell processes, microtubules, and occasional dense-core granules. Whether this neuroectodermal tumor represents a separate entity or is a variant of Ewing's sarcoma should wait for further experience, in the light of recent evidence suggesting that Ewing's sarcoma arises from primitive multipotential cells.

A femoral Ewing's sarcoma from a 13 1/2-year-old girl with otherwise typical clinical and pathological features showed epithelial differentiation by electron microscopy and immunocytochemistry. The expression of keratin and the presence of tonofilaments in cells of this Ewing's sarcoma may enforce the hypothesis that Ewing's sarcoma derives from a multipotential primitive stem cell.