summary Fibrous Dysplasia is a developmental abnormality caused by a GS alpha protein mutation that leads to failure of the production of normal lamellar bone. The condition usually presents in patients who are less than 30 years of age with an asymptomatic lesion that is found incidentally on radiographs. Diagnosis is made with radiographs showing a lesion with ground glass appearance or a "punched-out" lesion with a well-defined margin of sclerotic bone. Treatment is usually nonoperative with bisphosphonates for pain control. Surgical management is indicated for lesions that lead to bone deformities such as scoliosis or coxa vara. 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 Anatomic location any bone can be involved the proximal femur is most common site, followed by rib, maxilla, and tibia Etiology 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 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 ("coast of Maine") than neurofibromatosis may or may not be present with fibrous dysplasia by definition present with McCune-Albright syndrome swelling around lesion scoliosis 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 Differential Fibrous Dysplasia Differential Multiple lesions in young patients Treatment is Observation alone Benefits from Bisphonate therapy Fibrous Dysplasia o o o Eosinophilic granuloma o o Lymphoma o Leukemia o Enchondroma / Olliers / Maffucci's o o Osteochondroma / MHE o o NOF /Jaffe-Campanacci syndrome o o Hemangioendothelioma o Paget's o o Metastatic Disease o Myeloma o Prognosis 1% risk of malignant transformation to osteosarcoma, fibrosarcoma, or malignant fibrous histiocytoma poor prognosis
QUESTIONS 1 of 18 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 Previous Next Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK (OBQ18.131) Which of the following is associated with a mutation in the GNAS gene? QID: 213027 Type & Select Correct Answer 1 Fibrosarcoma 10% (160/1632) 2 Chondroblastoma 5% (75/1632) 3 Fibrous dysplasia 69% (1123/1632) 4 Osteoblastoma 4% (58/1632) 5 Osteofibrous dysplasia 12% (202/1632) L 3 Question Complexity A Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 3 Review Tested Concept Review Full Topic 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? QID: 4911 FIGURES: A B Type & Select Correct Answer 1 Neurofibromatosis 14% (818/5654) 2 Holt-Oram Syndrome 2% (99/5654) 3 McCune-Albright Syndrome 82% (4640/5654) 4 Fibular hemimelia 0% (6/5654) 5 Ellis-van-Creveld Syndrome 1% (51/5654) L 2 Question Complexity B Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 3 Review Tested Concept Review Full Topic 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? QID: 2887 Type & Select Correct Answer 1 Fibrous dysplasia 82% (1894/2313) 2 Diastrophic dysplasia 6% (130/2313) 3 Cleidocranial dysostosis 3% (66/2313) 4 Osteogenesis imperfecta 5% (114/2313) 5 Achondroplasia 4% (103/2313) L 1 Question Complexity B Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 1 Review Tested Concept Review Full Topic (OBQ09.21) All of the following are characteristic of McCune-Albright syndrome EXCEPT? QID: 2834 Type & Select Correct Answer 1 Caused by a mutation in G(s)alpha subunit 10% (275/2810) 2 Cafe-au-lait spots 4% (120/2810) 3 Polyostotic fibrous dysplasia 5% (127/2810) 4 Multiple neurofibromas 77% (2152/2810) 5 Precocious puberty 4% (124/2810) L 2 Question Complexity B Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 4 Review Tested Concept Review Full Topic Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK (OBQ07.231) 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? QID: 892 FIGURES: A B C Type & Select Correct Answer 1 Adamantinoma 21% (558/2678) 2 Osteomyelitis 1% (20/2678) 3 Fibrous dysplasia 66% (1771/2678) 4 Osteosarcoma 8% (205/2678) 5 Stress fracture 4% (110/2678) L 1 Question Complexity C Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 3 Review Tested Concept Review Full Topic (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? QID: 687 FIGURES: A B C D E Type & Select Correct Answer 1 Figure A 17% (349/2093) 2 Figure B 4% (74/2093) 3 Figure C 6% (127/2093) 4 Figure D 10% (201/2093) 5 Figure E 63% (1323/2093) L 2 Question Complexity C Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 5 Review Tested Concept Review Full Topic (OBQ06.240) A genetic abnormality in the cyclic AMP signaling pathway is involved in which of the following conditions? QID: 251 Type & Select Correct Answer 1 Achondroplasia 10% (167/1701) 2 Hypochondroplasia 4% (61/1701) 3 Multiple hereditary exostosis 12% (207/1701) 4 Fibrous dysplasia 66% (1124/1701) 5 Neurofibromatosis type I 8% (138/1701) L 2 Question Complexity B Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 4 Review Tested Concept Review Full Topic
All Videos (1) Podcasts (1) Login to View Community Videos Login to View Community Videos Histopathology of fibrous dysplasia Basem Attum (OB Team Editor) General - Fibrous Dysplasia C 11/9/2014 366 views 3.6 (5) Pathology⎪Fibrous Dysplasia Pathology - Fibrous Dysplasia Listen Now 16:5 min 10/15/2019 389 plays 5.0 (6)
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