Introduction A developmental abnormality caused by failure of the production of normal lamellar bone areas of the skeleton remain poorly mineralized trabeculae Epidemiology demographics male:female ratio females > males age bracket found in any and all ages onset for 75% of patients at <30 years of age location any bone can be involved the proximal femur is most common site, followed by rib, maxilla, and tibia Genetics associated with GNAS mutation GS alpha protein (chromosome 20q13) activating mutation (affects cAMP signaling pathway leading to increased production of cAMP) high production of FGF-23 which may lead to hypophosphatemia Associated conditions orthopedic manifestations McCune Albright syndrome condition defined by the presence of skin abnormalities (cafe au lait spots in coast of Maine pattern) endocrine abnormalities (precocious puberty)\ renal phosphate wasting due to FGF-23 (oncogenic osteomalacia) unilateral polyostotic fibrous dysplasia obtain AP spine radiographs to look for scoliosis Mazabraud syndrome polyostotic fibrous dysplasia soft-tissue intramuscular myxomas Osteofibrous dysplasia rare form that primarily affects the tibia and is confined to the cortices nonorthopedic manifestations severe cranial deformities with blindness Prognosis 1% risk of malignant transformation to osteosarcoma, fibrosarcoma, or malignant fibrous histiocytoma poor prognosis Presentation Symptoms usually asymptomatic and discovered as an incidental finding may have swelling or deformity bone lesions may be monostotic (80%) or polystotic (20%) pain from stress fractures Physical exam inspection cafe au lait spots larger and more irregular borders than neurofibromatosis may or may not be present with fibrous dysplasia by definition present with McCune-Albright syndrome swelling around lesion Imaging Radiographs hip/pelvis radiograph central lytic lesions in medullary canal (diaphysis or metaphysis) may have cortical thinning with expansile lesion highly lytic lesions or a ground glass appearance "punched-out" lesion with well defined margin of sclerotic bone is common modest expansion of bone Shepherd's crook deformity AP spine radiograph vertebral collapse kyphoscoliosis Bone scan usually warm Studies Gross - yellow-white gritty tissue Histology characteristic look of "alphabet soup" or "chinese letters" fibroblast proliferation surrounding islands of woven bone woven bone lacks osteoblastic rimming (osteofibrous dysplasia has osteoblastic rimming) trabeculae of osteoid and bone in fibrous stroma with metaplastic cartilage or areas of cyst degeneration mitotic figures are common Treatment Nonoperative observation indications asymptomatic patients Bisphosphonate therapy indications symptomatic polyostotic fibrous dysplasia effective in decreasing pain and reducing bone turnover Operative internal fixation and bone grafting indications symptomatic lesions impending/actual fractures through lesions in areas of high stress (femoral neck) severe deformity neurologic compromise in the spine technique never use autogenous cancellous bone, as the transplanted bone will quickly turn into fibrous dysplastic woven bone use cortical or cancellous allografts intramedullary device more effective than a plate in the lower extremity osteotomies indications coxa vara deformity intertrochanteric osteotomy Differentials & Groups Multiple lesions in young patients (1) Treatment is Observation alone (2) Benefits from Bisphonate therapy Fibrous dysplasia • • • Eosinophilic granuloma • • Lymphoma • Leukemia • Enchondroma / Olliers / Marfucci's • • Osteochondroma / MHE • • NOF / Jaffe-Campanacci syndrome • • Hemangioendothelioma • Paget's • • Metastatic Disease • Myeloma • ASSUMPTIONS: (1) Younger patient is < 40 yrs; (2) assuming aymptomatic and no impending fracture IBank Location Age Xray Xray CT B. Scan MRI MRI Histo(1) Case A fibula 10 yrs. Case A spine Case B radius Case C humerus Case D skull (1) - histology does not always correspond to clinical case
QUESTIONS 1 of 17 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 Previous Next Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK (SBQ13PE.1) A 6-year-old being evaluated in your clinic presents with the clinical findings and radiographs shown in Figures A and B. What is the most likely diagnosis? Review Topic | Tested Concept QID: 4911 FIGURES: A B Type & Select Correct Answer 1 Neurofibromatosis 15% (771/5190) 2 Holt-Oram Syndrome 2% (91/5190) 3 McCune-Albright Syndrome 82% (4238/5190) 4 Fibular hemimelia 0% (5/5190) 5 Ellis-van-Creveld Syndrome 1% (48/5190) L 2 Question Complexity B Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 3 Review tested concept Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK (OBQ09.74) A mutation in a G(s) alpha protein (activating G protein that increases cAMP) results in which of the following diseases? Review Topic | Tested Concept QID: 2887 Type & Select Correct Answer 1 Fibrous dysplasia 82% (1605/1967) 2 Diastrophic dysplasia 6% (110/1967) 3 Cleidocranial dysostosis 3% (58/1967) 4 Osteogenesis imperfecta 5% (101/1967) 5 Achondroplasia 5% (89/1967) L 1 Question Complexity B Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 1 Review tested concept (OBQ09.21) All of the following are characteristic of McCune-Albright syndrome EXCEPT? Review Topic | Tested Concept QID: 2834 Type & Select Correct Answer 1 Caused by a mutation in G(s)alpha subunit 10% (255/2504) 2 Cafe-au-lait spots 4% (109/2504) 3 Polyostotic fibrous dysplasia 5% (113/2504) 4 Multiple neurofibromas 76% (1909/2504) 5 Precocious puberty 4% (108/2504) L 2 Question Complexity B Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 4 Review tested concept Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK (OBQ07.26) The G-protein coupled family of receptors play a crucial role in transmembrane cytokine signaling. Point mutation in the Gs-alpha subunit of this receptor is responsible for a specific bone/soft tissue disease. Which of the following radiographs corresponds to this disease? Review Topic | Tested Concept QID: 687 FIGURES: A B C D E Type & Select Correct Answer 1 Figure A 16% (295/1880) 2 Figure B 3% (65/1880) 3 Figure C 6% (108/1880) 4 Figure D 9% (167/1880) 5 Figure E 65% (1227/1880) L 2 Question Complexity C Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 5 Review tested concept (OBQ07.231) A 17-year-old high-school track athlete complains of vague pain along his knee. He denies any specific trauma to this area. A radiograph is seen in Figure A. A biopsy specimen in low and high power is seen in Figure C and D, respectively. What is the most likely diagnosis? Review Topic | Tested Concept QID: 892 FIGURES: A B C Type & Select Correct Answer 1 Adamantinoma 23% (532/2353) 2 Osteomyelitis 1% (13/2353) 3 Fibrous dysplasia 65% (1534/2353) 4 Osteosarcoma 7% (158/2353) 5 Stress fracture 5% (106/2353) L 3 Question Complexity C Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 3 Review tested concept (OBQ06.240) A genetic abnormality in the cyclic AMP signaling pathway is involved in which of the following conditions? Review Topic | Tested Concept QID: 251 Type & Select Correct Answer 1 Achondroplasia 10% (137/1432) 2 Hypochondroplasia 3% (48/1432) 3 Multiple hereditary exostosis 13% (185/1432) 4 Fibrous dysplasia 66% (945/1432) 5 Neurofibromatosis type I 8% (114/1432) L 2 Question Complexity B Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 4 Review tested concept
All Videos (1) Podcasts (1) Upgrade to View Premium Videos Upgrade to View Premium Videos Histopathology of fibrous dysplasia Basem Attum (OB Team Editor) General - Fibrous Dysplasia 11/9/2014 334 views (5) Pathology⎪Fibrous Dysplasia Team Orthobullets 4 Pathology - Fibrous Dysplasia Listen Now 6:12 min 10/15/2019 129 plays (5)
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