Osteomalacia in the elderly: the value of radio-isotope bone scanning in patients with equivocal biochemistry.

Radio-isotope bone scanning was used to detect osteomalacia in 17 elderly subjects who had equivocal biochemical evidence of this condition. The scan was positive in 10 of the 17 subjects. Bone biopsy confirmed osteomalacia in all 10, but also identified a further two cases. Isotope bone scanning is a practical and relatively non-invasive method of detecting osteomalacia in elderly subjects.

An unusual intraosseous lesion with fibroblastic, osteoclastic, osteoblastic, aneurysmal and fibromyxoid elements. "Solid" variant of aneurysmal bone cyst.

Four examples are reported of an unusual noncystic intraosseous lesion which does not conform to any hitherto recognized entity and which can be mistaken, not only by the general histopathologist but by the osteoarticular pathologist, for a variety of other conditions, including sarcoma and giant-cell tumor. They were in patients aged 5 to 13 years; three in the spine, one in the ethmoid. Local excision, supplemented by low-dose radiotherapy in cases with cord compression, produced a satisfactory outcome in all cases. At presentation the radiologic findings were nonspecific but, following treatment, an eggshell rim of bone developed in those lesions which had been incompletely excised. Histologically, they are characterised by florid fibroblastic or fibrohistiocytic proliferation, osteoblastic differentiation with osteoid production, areas rich in osteoclast-type giant cells, aneurysmal sinusoids, and occasional foci of degenerate calcifying fibromyxoid tissue. Because this combination of histologic features can be found in the solid parts of aneurysmal bone cyst and in no other condition, at this centre we have regarded this lesion as a variant of aneurysmal bone cyst devoid of any cystic component.

Enchondromata with annular calcification in association with fibrous dysplasia.

Annular or ring calcification is described in conjunction with fibrous dysplasia in four of 110 patients culled from the Bristol Bone Tumour Registry. This feature results from endochondral calcification and ossification within cartilage rests or chondromata developing pari passu with fibrous dysplasia. Statistically the condition is more likely to be present in the polyostotic form of fibrous dysplasia (17%) than in the monostotic form (circa 1%). All patients were male and the diagnosis of fibrous dysplasia was established between the time of birth and the age of 16. Ring calcification was first detected between the ages of three and 16 years and persisted into adult life. Calcification almost exclusively involved the lower limbs particularly around the knee and above the ankle. In the three polyostotic cases rapid and gross extentsion of the cartilaginous component of the disease occurred at the time of the adolescent growth spurt. When present in a patient with fibrous dysplasia the appearance are typical and signify and associated benign enchondromatous process. No suspicion of chondrosarcoma should arise.

Malignancy, aggressiveness, and recurrence in giant cell tumor of bone.

Eighty-six cases of giant cell bone tumor were reviewed with particular attention to frank sarcomatous changes, abnormal mitoses, permeation of vascular channels, and the number of mitoses per square millimeter, and the results were analyzed in relation to malignancy, aggressiveness, and recurrence. There were 4 cases of malignant (Grade III) tumor (about 5%) showing frank sarcomatous changes. Eight (9%) were considered cases of borderline (Grade II+) tumor, without frank sarcomatous changes but showing abnormal mitoses or vascular permeation. Seventy-four (86%) were cases of conventional giant cell tumor (Grades I and II). Mitotic counts did not categorically distinguish the three groups because of overlap. Recurrence essentially reflected the inadequacy of treatment. Metastases were observed only in the malignant group. About a quarter of conventional giant cell tumors were considered aggressive on clinical or radiologic grounds, but these could not be identified on a histologic basis. Tumors with minimal mitotic activity (1/mm2 or less) were almost exclusively nonaggressive. Post-irradiation sarcomas, best regarded as independent new tumors, developed in 4 cases (about 5%).

Malignant transformation of osteoblastoma.

A recurrent spinal tumor confidently diagnosed as osteoblastoma eventually terminated as a sclerosing osteoblastic which metastasised nine years after the onset of symptoms.

Definitions of osteosarcoma, chondrosarcoma, and fibrosarcoma of bone.

The current definition of osteosarcoma, based on the prescence of tumor osteoid, is unsatisfactory because it fails to identify some examples of chondroblastic, fibroblastic, and anaplastic osteosarcoma having no demonstrable tumor osteoid. The tumor cells in osteosarcoma, whether osteoblastic, chondroblastic, fibroblastic, or anaplastic, contain abundant alkaline phsophatase, whereas this enzyme is scanty or absent in condrosarcoma and fibrosarcoma. It is therefore proposed that these bone sarcomas are best defined according to the origin of the constituent tumor cells and their alkaline phosphatase content: osteosarcoma--a malignant tumor of osteoblasts (alkaline phosphatase positive); chondrosarcoma--a malignant tumor of chondroblasts (alkaline phosphatase negative); and fibrosarcoma--a malignant tumor of fibroblasts (alkaline phosphatase negative).

The diagnosis and grading of chondrosarcoma of bone: a combined cytologic and histologic approach.

The diagnosis and grading of chondrosarcoma of bone is best established by a complementary study of its cytology, as observed in smeared preparations, and of its tissue structure and relationship to the host bone, as observed in histologic sections. Smeared preparations demonstrate the cytologic features of chondrosarcoma with greater clarity and detail than is possible with histologic sections. Histology is particularly helpful in the diagnosis of low-grade chondrosarcoma, through the demonstration of its invasive activity in relation to the host bone. The importance of grading chondrosarcoma is emphasized because of its relevance to the biological behaviour and prognosis of this tumor.

A review of the behaviour of chondrosarcoma of bone.

Sixty-two cases of chondrosarcoma of bone were reviewed and histologically graded as low, medium or high-grade tumours. After excluding patients dead from unrelated causes or lost to follow-up, forty cases were available for ten-year follow-up and fifty-eight for five-year follow-up. The rates of survival, recurrence and metastasis were analysed according to the histological grading. Recurrence was further analysed according to the adequacy of treatment. The results were compared with those previously reported in the literature. There was a ten-year survival rate of 58 per cent. Recurrence developed in 58 per cent and was uncontrollable in 29 per cent. The recurrence rate was 87 per cent with inadequate treatment and 15 per cent with adequate treatment. Recurrences outside the limb bones usually proved uncontrollable; recurrences in the limb bones were amenable to further, and if necessary repeated, operations. High-grade chondrosarcoma had a metastatic risk of 75 per cent and eventual mortality of 88 per cent. Medium-grade chondrosarcoma had a metastatic risk of 14 per cent and a mortality of 60 per cent. Low-grade chondrosarcoma had a metastatic risk of 5 per cent and a mortality of 29 per cent.

Primary leiomyosarcoma of the bone and its comparison with fibrosarcoma.

Two cases of primary leiomyosarcoma of the bone are recorded, one in the distal fibula of a 66-year-old man, the other in the proximal tibia of a 61-year-old woman. The cytological, histological, and ultrastructural features of leiomyosarcoma of bone are described and compared with those of fibrosarcoma. These features are sufficiently characteristic to enable a confident diagnostic distinction between leiomyosarcoma and fibrosarcoma. Nevertheless, certain basic similarities exist between these two tumors, manifested at the ultrastructural level by the presence of myofilaments in fibrosarcoma; it would seem that the observed differences relate to the degree of development of the myofilamentous structures. It is postulated that primary leiomyosarcoma of the bone need not necessarily always arise from the media of blood vessels; it might also conceivably develop through advanced myogenic metaplasia of a sarcoma originating from fibroblastic tissue.

Fibrosarcomata and malignant fibrous histiocytomata arising in relation to enchondromata.

Six cases are reported in which a fibrosarcoma or malignant fibrous histiocytoma developed in relation to an enchondroma in a long bone. Four of the tumours were fibrosarcomata, and two were malignant fibrous histiocytomata. Five of the six cases were in the distal femur, which is a common site for old calcified enchondromata or "cartilage rests". The age of the patients was between fifty-six and eighty-six with a mean of seventy. Four were women, Five died less than one year after presentation. The fibrosarcomata and malignant fibrous histiocytomata do not appear to have arisen directly from the tumour cartilage but from the dense fibrous tissue surrounding necrotic areas in the enchondromata by a process analogous to that responsible for the development of fibrosarcomata in bone infarcts and chronic osteomyelitis. The possibility that some "dedifferentiated" chondrosarcomata are forms of collision tumour is discussed.

Old fibrin coagula and their ossification in simple bone cysts.

Old calcified fibrin coagula are frequently found in simple bone cysts. They provide a scaffold on which new bone is laid down, in a process analogous to endochondral ossification. It is suggested that these coagula are derived in substantial part from the plasma-like contents of the cyst, after the release of plasma-clotting factors as the result of injury. Major haemorrhage is not involved and in many cases there is no antecedent fracture. The phenomenon is not seen in other common cystic conditions of bone and its recognition is thus helpful in the histological diagnosis of simple bone cyst. Cystic bone infarcts and their possible confusion with simple bone cysts are also briefly discussed.