Introduction Also referred to as a simple bone cyst A non-neoplastic, serous fluid-filled bone lesion thought to result from temporary failure of medullary bone formation near the physis Age & location age usually found in patients <20 years of age location usually found in the proximal humerus of young patients can be found in other locations including proximal femur, distal tibia, ilium, calcaneus, and occasionally metacarpals, phalanges, or distal radius arises in the metaphysis adjacent to physis and progresses toward the diaphysis with bone growth Prognosis as a patient approaches skeletal maturity, a UBC will often decrease in size and may heal after growth is complete fracture healing usually does not lead to cyst resolution requires close follow up while in active phase due to recurrence and risk of fracture or growth arrest Classification Classification is important as it impacts treatment active if cyst is adjacent to the physis latent if normal bone separates cyst from physis Presentation Symptoms most asymptomatic unless fracture occurs (usually with minor trauma) presents with pain from a pathologic fracture in ~50% Imaging Radiographs central, lytic, well-demarcated metaphyseal lesion (2-3% cross physis) cystic expansion with symmetric thinning of cortices "fallen leaf" sign (pathologic fracture with fallen cortical fragment in base of empty cyst is pathognomonic) trabeculated appearance after multiple fractures MRI very dark on T1 very bright on T2 gadolinium shows classic rim enhancement of a cystic lesion Bone scan is variable, but usually warm Labs Specific laboratory tests usually not required Histology Characteristic findings cyst with thin fibrous lining containing fibrous tissue, giant cells, and hemosiderin pigment chronic inflammatory cells may be found in small numbers cementum spherules (calcified eosinophilic fibrinous material) in 10% uniform population of spindle cells without nuclear atypia Biopsy usually indicated for questionable diagnosis Differential ABC is more expansive than UBC (UBC lesion usually not wider than physis) Telangiectatic osteosarcoma Treatment Nonoperative immobilization alone indications proximal humerus lesions with pathologic fracture (15% of lesions fill in with native bone after acute fracture) aspiration/methylprednisolone acetate injection indications active cysts (communicates with physis) in the proximal humerus technique usually requires several injections, especially in very young children bone marrow injections have recently been reported to be effective Operative curettage and bone grafting +/- internal fixation based on tumor location indications symptomatic latent cysts that have not responded to steroid injections latent cysts in the proximal femur that are a structural concern and at risk for fracture and osteonecrosis proximal femoral lesions with a pathologic fracture have a high rate of refracture and malunion when treated nonoperatively therefore, internal fixation is recommended contraindications avoid in active lesions as communication with physis may lead to growth arrest Differentials & Groups "Bubbly" lytic lesion on xray Treatment is USUALLY Aspiration and Injection Treatment is OCCASIONALLY curettage and bone grafting. UBC • • • ABC • NOF • • Enchondroma • Ibank Location Xray Xray CT B. Scan MRI MRI Histo(1) Case A femur Case A humerus Case A humerus (1) - histology does not always correspond to clinical case
QUESTIONS 1 of 20 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 Previous Next You have 100% on this question. Just skip this one for now. Take This Question Anyway (OBQ15.162) A 10-year-old boy injured his right shoulder playing lacrosse. He denies previous shoulder pain or injury. Radiographs of the shoulder are shown in Figure A. What is the next best step in management? Review Topic | Tested Concept QID: 5847 FIGURES: A Type & Select Correct Answer 1 Urgent biopsy 4% (116/2935) 2 CT scan of arm 3% (100/2935) 3 Whole body bone scan 2% (52/2935) 4 Open reduction and plate fixation 1% (42/2935) 5 Sling for comfort 89% (2614/2935) L 1 Question Complexity A Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 5 Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK You have 100% on this question. Just skip this one for now. Take This Question Anyway (OBQ14.187) A 16-year-old girl presents with hip and thigh pain for 3 months. Examination reveals an antalgic gait. A radiograph, coronal MRI scans (T1 pre- and post-contrast, and T2), and biopsy are shown in Figures A through E. What is the most likely diagnosis? Review Topic | Tested Concept QID: 5597 FIGURES: A B C D E Type & Select Correct Answer 1 Unicameral bone cyst 61% (2146/3541) 2 Aneurysmal bone cyst 12% (422/3541) 3 Fibrous dysplasia 14% (479/3541) 4 Osteofibrous dysplasia 8% (270/3541) 5 Eosinophilic granuloma 6% (200/3541) L 3 Question Complexity B Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 1 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 You have 100% on this question. Just skip this one for now. Take This Question Anyway (SBQ11PA.92) What is the most common anatomical site for unicameral bone cysts in children? Review Topic | Tested Concept QID: 4117 Type & Select Correct Answer 1 Distal humerus 1% (25/3985) 2 Proximal humerus 91% (3633/3985) 3 Distal femur 4% (146/3985) 4 Proximal tibia 3% (109/3985) 5 Tibial shaft 1% (52/3985) L 1 Question Complexity B Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 2 You have 100% on this question. Just skip this one for now. Take This Question Anyway (OBQ11.268) An 11-year-old boy presents with acute right arm pain after throwing a baseball. He is otherwise healthy and has no other complaints. Radiograph and CT scan of the lesion are shown in Figures A and B. What is the most appropriate treatment? Review Topic | Tested Concept QID: 3691 FIGURES: A B Type & Select Correct Answer 1 Biopsy 8% (151/1915) 2 Immobilization 89% (1705/1915) 3 Intramedullary nailing and chemotherapy 1% (27/1915) 4 Wide resection and radiation therapy 1% (23/1915) 5 Amputation 0% (4/1915) L 1 Question Complexity A Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 2 Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK You have 100% on this question. Just skip this one for now. Take This Question Anyway (OBQ08.63) A 9-year-old child presents to your office after he felt a painful snap in his arm while throwing a baseball. He is otherwise in good health and has no family history of disease. A radiograph of his arm is shown in Figure A. What is the next step in your management? Review Topic | Tested Concept QID: 449 FIGURES: A Type & Select Correct Answer 1 Sling for comfort 84% (1558/1859) 2 Tumor staging 2% (34/1859) 3 Biopsy 11% (206/1859) 4 Open reduction with internal fixation 2% (37/1859) 5 Intramedullary nailing 1% (17/1859) L 1 Question Complexity C Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 1 Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK You have 100% on this question. Just skip this one for now. Take This Question Anyway (OBQ07.51) An 8-year-old boy injures his arm pulling open a car door. A radiograph is shown in Figure A. Which of the following is the most likely diagnosis and preferred initial treatment? Review Topic | Tested Concept QID: 712 FIGURES: A Type & Select Correct Answer 1 Giant cell tumor of bone, Open biopsy and curettage of tumor 2% (33/1615) 2 Unicameral bone cyst, Aspiration of fluid and injection of bone cement 9% (151/1615) 3 Non-Ossifying Fibroma, Radiation 1% (15/1615) 4 Unicameral bone cyst, Sling and swath 87% (1409/1615) 5 Telangietic osteosarcoma, Chemotherapy 0% (1/1615) L 1 Question Complexity A Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 4 You have 100% on this question. Just skip this one for now. Take This Question Anyway (SBQ07PE.38) An 8-year-old boy complains of left shoulder pain after a collision with his younger brother. He was asymptomatic prior to the incident. Which of the following treatments is most appropriate at this time? Review Topic | Tested Concept QID: 1523 FIGURES: A Type & Select Correct Answer 1 Aspiration and injection of methylprednisolone acetate 2% (32/1346) 2 Open reduction, internal fixation 3% (44/1346) 3 Initiation of radiation and chemotherapy 1% (10/1346) 4 Immobilization in sling 92% (1245/1346) 5 Radiofrequency ablation 1% (9/1346) L 1 Question Complexity A Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 4 You have 100% on this question. Just skip this one for now. Take This Question Anyway This is an AAOS Self Assessment Exam (SAE) question. Orthobullets was not involved in the editorial process and does not have the ability to alter the question. If you prefer to hide SAE questions, simply turn them off in your Learning Goals. (SAE07PE.38) Figure 16 shows the radiograph of a 7-year-old boy who sustained a pathologic fracture of the left humerus 1 day ago. Initial management should consist of Review Topic | Tested Concept QID: 6098 FIGURES: A Type & Select Correct Answer 1 a sling and swathe. 73% (198/272) 2 needle biopsy of the lesion. 16% (44/272) 3 a corticosteroid injection of the lesion. 0% (0/272) 4 curettage and bone packing of the lesion. 8% (23/272) 5 insertion of an intramedullary rod. 1% (2/272) L 3 Question Complexity E Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 1 You have 100% on this question. Just skip this one for now. Take This Question Anyway (SBQ06BS.1) A 14-year-old boy is brought to the emergency department after falling onto his right shoulder. Radiographs are shown in Figure A. Which of the following is most likely complication to occur with curettage and bone grafting of this lesion? Review Topic | Tested Concept QID: 2513 FIGURES: A Type & Select Correct Answer 1 Metastases to the lungs 3% (18/655) 2 Recurrence of the lesion 68% (448/655) 3 Limb-length discrepancy of the affected side compared to the contralateral side 20% (133/655) 4 Continued pain in the affected extremity 7% (47/655) 5 Paraneoplastic disease 1% (4/655) L 2 Question Complexity D Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 2 You have 100% on this question. Just skip this one for now. Take This Question Anyway (SBQ05PA.99) A 10-year-old boy complains of shoulder pain after falling while skateboarding. His injury radiograph is shown in Figure A. What is the most appropriate next step in treatment? Review Topic | Tested Concept QID: 2084 FIGURES: A Type & Select Correct Answer 1 Immobilization alone 79% (1468/1864) 2 MRI 10% (184/1864) 3 Open reduction, percutaneous fixation 2% (29/1864) 4 Aspiration/methylprednisolone acetate injection 2% (31/1864) 5 Curettage and bone grafting 8% (144/1864) L 2 Question Complexity A Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 1 You have 100% on this question. Just skip this one for now. Take This Question Anyway (SBQ05PA.44) Which of the following figures represents the histological slide of a tumor that is most likely to present with a pathologic fracture in a child? Review Topic | Tested Concept QID: 2029 FIGURES: A B C D E Type & Select Correct Answer 1 Figure A 51% (913/1785) 2 Figure B 7% (120/1785) 3 Figure C 18% (329/1785) 4 Figure D 14% (246/1785) 5 Figure E 9% (167/1785) L 5 Question Complexity D Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 3 You have 100% on this question. Just skip this one for now. Take This Question Anyway (OBQ05.144) A 7-year old boy experienced severe right hip pain following ice-skating. He previously had no hip pain and is otherwise healthy. Radiographs are shown in figures A and B. What is the recommended treatment ? Review Topic | Tested Concept QID: 1030 FIGURES: A B Type & Select Correct Answer 1 Open biopsy and pathological staging without fracture fixation 9% (155/1734) 2 Open reduction and internal fixation with bone grafting of the bone cyst 81% (1409/1734) 3 Bedrest for 4 weeks followed by progressive weight-bearing as tolerated 3% (49/1734) 4 Immediate hip spica casting 6% (108/1734) 5 Tibial traction pin with 4 weeks of skeletal traction followed by open biopsy 0% (8/1734) L 2 Question Complexity C Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 2 You have 100% on this question. Just skip this one for now. Take This Question Anyway (OBQ04.54) A 15-year-old boy twists his ankle and is brought to the emergency room. Radiographs are shown in Figure A. What is the most likely progression of the this lesion as the child reaches skeletal maturity? Review Topic | Tested Concept QID: 1384 FIGURES: A Type & Select Correct Answer 1 Increase in size and involve the entire bone 2% (19/1111) 2 Decrease in size and may disappear altogether 86% (960/1111) 3 Turn into a malignant tumor 0% (2/1111) 4 Remain unchanged 11% (120/1111) 5 Lead to deformity of the affected bone 1% (9/1111) L 1 Question Complexity D Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 2
All Videos (1) Podcasts (1) Upgrade to View Premium Videos Upgrade to View Premium Videos oncology Orthopedic Oncology Course - Radiolucent Lesions of Bone (GCT, ABC, UBC) - Lecture 7 Mohammed Al Sobeai Pathology - Unicameral Bone Cyst 3/1/2017 726 views Pathology⎪Unicameral Bone Cyst Team Orthobullets 4 Pathology - Unicameral Bone Cyst Listen Now 8:52 min 10/15/2019 110 plays
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