1 . Twenty patients with fibrous dysplasia, confirmed histologically, are reported and discussed in regard to classification, etiology, pathogenesis and treatment. The various fibrous or fibrocystic lesions of bone are characterised briefly for purpose of contrast, and the position of fibrous dysplasia in this heterogeneous collection is suggested. 2. The classification of fibrous dysplasia based on the degree of skeletal involvement is used, and the diagnostic, therapeutic and prognostic implications of this classification emphasised. The authors endorse the opinion that fibrous dysplasia is a developmental defect. Clinical, histological and radiographic evidence is presented to point to the distinct evolution of the monostotic lesions, to which a positive and aggressive approach is recommended

Monostotic fibrous dysplasia of the proximal femur has a variable clinical course, despite its reported limited tendency to progress. We investigated the natural history and predisposing factors for progression of dysplasia in a group of 76 patients with a mean follow-up of 8.5 years (2.0 to 15.2). Of these, 31 (41%) presented with an asymptomatic incidental lesion while 45 (59%) presented with pain or a pathological fracture. A group of 23 patients (30%) underwent early operative treatment for pain (19: 25%) or pathological fracture (4: 5%). Of the 53 patients who were initially treated non-operatively, 45 (85%) remained asymptomatic but eight (15%) needed surgery because of pain or fracture. The progression-free survival of the observation group was 81% (. sd. 6.4%) at five-years follow-up. An initial presentation of pain (p < 0.001), a limp (p < 0.001), radiological evidence of microfracture (p = 0.001) and younger age (< 17 years) (p = 0.016) were significant predisposing factors for disease progression. The risk of experiencing pain or pathological fracture is considerable in monostotic fibrous dysplasia of the proximal femur. Patients presenting with pain, a limp or radiological evidence of microfracture have a high chance of needing surgical treatment. Cite this article: Bone Joint J 2014;96-B:673–6

A brief review of the literature on malignant change occurring in fibrous dysplasia is given and a further case of a sarcoma arising in a patient with polyostotic fibrous dysplasia is reported

We report the case of a 12-year-old boy with polyostotic fibrous dysplasia of the upper femur in whom a massive customised polyethylene prosthesis functioned successfully for more than fifty years

Malignant transformation of fibrous dysplasia to chondrosarcoma is rare. We report a case in which malignancy developed in an area of fibrous dysplasia in the ilium. We believe this to be the second reported case at this site. Treatment was by excision of the hemipelvis including the ala of the sacrum. A review of the literature is presented

1. Monostotic fibrous dysplasia in the long bones occurs most frequently in adolescence. In the jaws it is found mainly in early adult life. It presents later in the ribs, probably because it is often asymptomatic in this site. 2. The disease is equally distributed in both sexes. 3. Reactivation may occasionally occur in later life and in pregnancy. 4. Successful surgical treatment is by no means always easily achieved, and requires, in addition to the problems of fracture fixation and the correction of deformity, careful consideration of the age of the patient, the activity of the lesion and the extent to which it involves the cortical bone

A patient with polyostotic fibrous dysplasia had several fractures of the right lower limb. An above-knee amputation was eventually performed, followed by arthrodesis of the hip. Five years later the stump became painful and swelled with dramatic rapidity. Biopsy showed that this was not due to malignant change, but that an aneurysmal bone cyst had developed in association with the fibrous dysplasia

1. A condition of fibrous dysplasia of the jaws occurring in four brothers and a sister has been under observation since 1931. 2. Three of the five patients have been operated upon for correction of grotesque deformity, with satisfactory results. 3. The pathological nature of the disorder is discussed

We describe our experience with vascularised bone grafting for the treatment of fibrous dysplasia of the upper limb in eight patients, five men and three women, aged between 17 and 36 years. The site was in the humerus in six and the radius in two. Persistent pain, progression of the lesion and pathological fracture with delayed union were the indications for surgical intervention. We used a vascularised fibular graft after curettage of the lesion. Function and radiological progress were serially monitored. Early radiological union of the graft occurred at periods ranging from 8 to 14 weeks. The mean period for reconstitution of the diameter of the bone was 14 months (12 to 18) predominantly through inductive formation of bone around the vascularised graft, which was a prominent feature in all patients. There were no recurrences and none of the grafts sustained a fracture or failed to unite. After operation function was excellent in three patients and good in five. Vascularised bone grafts provide a safe and reliable means of ensuring good continuity of bone with little risk of recurrence and failure

An area of fibrous dysplasia of bone may undergo rapid enlargement which may be due to either cystic degeneration or malignant transformation. These complications may be clinically and radiologically indistinguishable and, unless both are borne in mind, incorrect management may follow. Magnetic resonance imaging was used in one of our cases and was the only imaging modality to demonstrate the true nature of the condition

1. A case of fibrous dysplasia in a woman aged fifty, with unilateral skeletal lesions, cutaneous pigmentation and possibly accelerated skeletal growth, is described. 2. At necropsy, the bony changes were found to be complicated by many of the changes of lipoid granulomatosis. Disseminated plaques of demyelinisation were found in the central nervous system. 3. The implications of the case are discussed

Deformity of the proximal femur in fibrous dysplasia leads to deviation of the mechanical axis of the hip, which may lead to the development of secondary osteoarthritis (OA). This study investigated the prevalence and predisposing factors for the development of OA in patients with fibrous dysplasia of the proximal femur. We reviewed the records of 209 patients from our institutional database with fibrous dysplasia of the proximal femur, investigating possible predisposing factors including patient demographics, the extent of the coxa vara deformity, the presence of peri-articular disease, and the overall burden of skeletal disease. Of the 209 patients, 24 (12%) had radiological evidence of OA in the ipsilateral hip. The prevalence was significantly higher in patients with polyostotic fibrous dysplasia compared with those with monostotic disease (p < 0.001). In a subgroup analysis of patients with polyostotic disease, the extent of deformity (quantified using the neck–shaft angle), and the presence of peri-articular disease (whether in the head of the femur or the acetabulum) were significant predictors of osteoarthritis (neck–shaft angle likelihood ratio (LR) = 0.847 per 1° increase, p = 0.004; presence of lesion in the head of the femur LR = 9.947, p = 0.027; presence of lesion in the acetabulum LR = 11.231, p = 0.014). . Our data suggest that patients with polyostotic fibrous dysplasia have a high risk of developing secondary OA of the hips. This risk is higher in patients with peri-articular disease, and those with a more severe deformity of proximal femur. Cite this article: Bone Joint J 2015;97-B:1007–11

1. Histochemical staining and correlated biochemical estimations of five hydrolytic enzymes were done on eighteen benign and twenty malignant fibroblastic lesions of bone and soft tissue. 2. Alkaline phosphatase activity was moderate in a fibroma and very high in fibrous dysplasia. In a typical fibrosarcoma the fibroblasts showed no enzyme activity and estimations were low. Exceptions indicated an osteogenic potential in the tumour. 3. ß-glucuronidase, leucine aminopeptidase, and to a less extent non-specific esterase, were more active in malignant than in benign lesions, and the highest activities were found in sarcomata arising in Paget's disease of bone. 4. Acid phosphatase showed no correlation with malignancy and was generally unremarkable except for high activity in osteoclasts, but was raised in two sarcomata that occurred after irradiation of giant-cell tumours. 5. A non-osteogenic fibroma and a fibrous cortical defect, though poorly represented in this series, are not uncommon; they sometimes lead to pathological fracture, but sarcoma is very rare in such lesions. They tend to show more alkaline phosphatase than fibrosarcoma but not the very high activity of fibrous dysplasia, which is related to its osteogenic potential. 6. Fibrous dysplasia most often presents in the five to fifteen age group but seldom leads to malignancy, though this may occur, usually as osteosarcoma, which has a similar high content of alkaline phosphatase. Fibrosarcoma is typically negative or very weak in this enzyme: the exceptional cases with high activity were tumours which were in part osteosarcoma. Generally the demonstration of high alkaline phosphatase activity in a fibroblastic lesion of bone, in the absence of trauma or inflammation, suggests the diagnosis of fibrous dysplasia

Pathological fractures in children can occur as a result of a variety of conditions, ranging from metabolic diseases and infection to tumours. Fractures through benign and malignant bone tumours should be recognised and managed appropriately by the treating orthopaedic surgeon. The most common benign bone tumours that cause pathological fractures in children are unicameral bone cysts, aneurysmal bone cysts, non-ossifying fibromas and fibrous dysplasia. Although pathological fractures through a primary bone malignancy are rare, these should be recognised quickly in order to achieve better outcomes. A thorough history, physical examination and review of plain radiographs are crucial to determine the cause and guide treatment. In most benign cases the fracture will heal and the lesion can be addressed at the time of the fracture, or after the fracture is healed. A step-wise and multidisciplinary approach is necessary in caring for paediatric patients with malignancies. Pathological fractures do not have to be treated by amputation; these fractures can heal and limb salvage can be performed when indicated

We report our experience of treating 17 patients with benign lesions of the proximal femur with non-vascularised, autologous fibular strut grafts, without osteosynthesis. The mean age of the patients at presentation was 16.5 years (5 to 33) and they were followed up for a mean of 2.9 years (0.4 to 19.5). Histological diagnoses included simple bone cyst, fibrous dysplasia, aneurysmal bone cysts and giant cell tumour. Local recurrence occurred in two patients (11.7%) and superficial wound infection, chronic hip pain and deep venous thrombosis occurred in three. Pathological fracture did not occur in any patient following the procedure. We conclude that non-vascularised fibular strut grafts are a safe and satisfactory method of treating benign lesions of the proximal femur

We present a retrospective study of patients suffering from a variety of benign tumours in whom external fixators were used to treat deformity and limb-length discrepancy, and for the reconstruction of bone defects. A total of 43 limbs in 31 patients (12 male and 19 female) with a mean age of 14 years (2 to 54) were treated. The diagnosis was Ollier’s disease in 12 limbs, fibrous dysplasia in 11, osteochondroma in eight, giant cell tumour in five, osteofibrous dysplasia in five and non-ossifying fibroma in two. The lesions were treated in the tibia in 19 limbs, in the femur in 16, and in the forearm in eight. The Ilizarov frame was used in 25 limbs, the Taylor Spatial Frame in seven, the Orthofix fixator in six, the Monotube in four and the Heidelberg fixator in one. The mean follow-up was 72 months (22 to 221). The mean external fixation period was 168 days (71 to 352). The mean external fixation index was 42 days/cm (22.2 to 102.0) in the 22 patients who required limb lengthening. The mean correction angle for those with angular deformity was 23° (7° to 45°). At final follow-up all patients had returned to normal activities. Four patients required a second operation for recurrent deformity of further limb lengthening. Local recurrence occurred in one patient, requiring further surgery

1. Four cases of polyostotic fibrous dysplasia are presented. 2. All are males, all show cutaneous pigmentation, and in two there has been precocious puberty. 3. The literature has been reviewed, and present conceptions of the pathology and etiology of the disease have been discussed. 4. The dysplasia if often confused with parathyroid osteodystrophy and sometimes the parathyroid glands are needlessly explored. This confusion should not arise if it is remembered that no general skeletal decalcification, and no constant changes in the blood calcium or phosphorus, occur in polyostotic fibrous dysplasia. The radiographic appearances of healing parathyroid osteodystrophy are, however, indistinguishable. 5. No effective therapy has been discovered for this disease. Pathological fractures and deformities may require treatment

We describe a schwannoma located in the mid-diaphyseal region of the fibula of a 14-year-old boy. Radiologically this was an expansile, lytic, globular and trabeculated lesion. MRI showed a narrow transition zone with a break in the cortex and adjacent tissue oedema. Differential diagnosis included schwannoma, fibrous dysplasia, giant cell tumour and aneurysmal bone cyst. The tumour was excised en bloc, with marginal resection limits, and there has been no recurrence two years after surgery. Histopathological examination confirmed the diagnosis of classic schwannoma. There were typical hypercellular Antoni A zones, less cellular Antoni B zones, and diffuse immunoreactivity to S100 protein. This is the first report of schwannoma involving a long bone in a child

Disarticulation of the hip in patients with high-grade tumours in the upper thigh results in significant morbidity. In patients with no disease of the proximal soft tissue a femoral stump may be preserved, leaving a fulcrum for movement and weight-bearing. We reviewed nine patients in whom the oncological decision would normally be to disarticulate, but who were treated by implantation of an endoprosthesis in order to create a functioning femoral stump. The surgery was undertaken for chondrosarcoma in four patients, pleomorphic sarcoma in three, osteosarcoma in one and fibrous dysplasia in one. At follow-up at a mean of 80 months (34 to 132), seven patients were alive and free from disease, one had died from lung metastases and another from a myocardial infarction. The mean functional outcome assessment was 50 (musculoskeletal tumor society), 50 and 60 (physical and mental Short-form 36 scores). Implantation of an endoprosthesis into the stump in carefully selected patients allows fitting of an above-knee prosthesis and improves wellbeing and the functional outcome

1. Alkaline and acid phosphatase, non-specific esterase and beta-glucuronidase have been estimated and demonstrated histochemically in a series of bone tumours and allied lesions, of which ten were osteogenic sarcomata, ten were giant-cell lesions, eleven were fibroblastic lesions and seven were tumours of cartilage. 2. Osteogenic sarcoma was found to be characterised by high levels of alkaline phosphatase, with rich staining for this enzyme in the tumour cells. Similar high levels of alkaline phosphatase were found in other bone-forming lesions, such as fibrous dysplasia, a giant-cell sarcoma with osteogenic matrix, and fracture callus. 3. Giant-cell lesions were characterised by high levels of acid phosphatase, and intense staining for this enzyme in the osteoclasts. These cells were also found to be rich in non-specific esterase (as shown by the alpha-naphthyl acetate method) and in beta-glucuronidase, but almost or entirely lacking in alkaline phosphatase. High levels of alkaline phosphatase were not found in giant-cell lesions except in relation to osteogenic matrix. 4. Fibroblastic tumours were characterised by moderate levels of all four enzymes, with little or no staining for phosphatases in the tumour cells; non-specific esterase was generally present in a proportion of the cells. 5. In certain lesions intermediate stages in the differentiation of fibroblasts to osteoblasts were found, notably in fibrous dysplasia, in which the biochemical change preceded the histological. In such lesions high total levels of alkaline phosphatase were found. 6. Cartilaginous tumours were characterised by low levels of all four enzymes, and little histochemical staining except in hypertrophied cells in areas of ossification. 7. It was found in general that the enzyme distributions in these neoplasms and other lesions reflected the findings in comparable reactive and growing normal tissues