Introduction Rare low-grade malignant tumor of unknown etiology that is almost always located in the mid-tibia Epidemiology incidence less than 300 cases have been documented demographics occurs in young adults (20 - 40 years of age) Associated conditions osteofibrous dysplasia historically, it was thought that osteofibrous dysplasia (OFD) was a precursor to this adamantinoma, however current studies have cast doubt on this theory Prognosis may metastasize to lungs (25%), therefore long-term followup is recommended recurrence is uncommon with negative margin excision Presentation Symptoms pain of months to years duration Physical exam bowing deformity or a palpable mass of tibia is common Imaging Radiographs multiple sharply circumscribed lucent lesions ("soap bubble" appearance) with interspersed sclerotic bone in mid tibia some lesions may destroy cortex may see bowing of the tibia radiographic evolution of lesions is helpful in the diagnosis as lesions may continue to grow and erode thru the cortex unlike other primary bone tumors, adamantinoma typically shows no periosteal reaction Studies Histology biphasic contains both epithelial and fibrous mesenchymal cells nests of epithelial-like cells arranged in palisading or glandular pattern stain for keratin background of fibrous stroma Treatment Operative wide-margin surgical resection indications standard of care in most patients techniques often requires intercallary resection with allograft or intercallary megaprosthesis reconstruction as adamantinoma is a low-grade malignancy, radiotherapy and/or chemotherapy is not typically used for local control of disease Differentials & Treatment Groups Osteofibrous dysplasia differentiating between osteofibrous dysplasia and adamantinoma is critical osteofibrous dysplasia is benign and treated with observation adamantinoma is malignant and treat with surgical resection Tibial diaphysis lesion Treated with wide-resection alone (2) Adamantinoma • • Osteofibrous dysplasia • Chondrosarcoma • Parosteal osteosarcoma • ASSUMPTIONS: (1) Older patient is > 40 yrs; (2) assuming no impending fracture Location Xray Xray CT B. Scan MRI MRI Histo(1) Case A tibia Case B tibia Case C tibia Case D tibia (1) - histology does not always correspond to clinical case
QUESTIONS 1 of 8 1 2 3 4 5 6 7 8 Previous Next Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK This is an AAOS Self assessment question. Orthobullets was not involved into the editorial process, and does not have the ability to alter. If you prefer to hide SAE questions on topics simply turn them off in your Content Settings (SAE08PA.43) A 30-year-old woman has had pain in her right leg for the past 6 months. A lytic lesion is noted in the anterior cortex of the midtibia, extending 5 cm in length without a soft-tissue mass. A radiograph and a biopsy specimen are shown in Figures 35a and 35b. What is the preferred treatment? Review Topic QID: 6304 FIGURES: A B 1 Debridement and IV antibiotics 5% (4/78) 2 Wide resection of the lesion 53% (41/78) 3 Chemotherapy alone 14% (11/78) 4 Observation 21% (16/78) 5 Amputation 8% (6/78) ML 4 Select Answer to see Preferred Response PREFERRED RESPONSE 2 Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK (OBQ12.31) A 28-year-old male presents for evaluation of leg pain. He denies trauma, and is otherwise healthy. A lateral radiograph of the affected leg is shown in Figure A. A biopsy is taken, and the low and high power histology specimens are shown in Figures B and C. Which of the following should be offered as definitive treatment of this lesion? Review Topic QID: 4391 FIGURES: A B C 1 Continued observation 5% (203/3794) 2 Radiation and chemotherapy 7% (248/3794) 3 Bracing to prevent tibial deformity and pathologic fracture 8% (312/3794) 4 Immediate above the knee amputation 3% (130/3794) 5 En bloc resection with wide margins followed by appropriate reconstruction 76% (2866/3794) ML 2 Select Answer to see Preferred Response PREFERRED RESPONSE 5 (OBQ11.122) A 21-year-old female presents with 7 years of leg pain and deformity. Radiographs from when she first noticed the lesion at age 14 are shown in Figures A and B. Current radiographs are shown in Figures C and D. Current MRI and histology section are shown in Figures E & F. What is the most likely diagnosis? Review Topic QID: 3545 FIGURES: A B C D E F 1 Osteofibrous dysplasia 25% (333/1319) 2 Adamantinoma 57% (751/1319) 3 Chronic osteomyelitis 1% (16/1319) 4 Periosteal osteosarcoma 2% (29/1319) 5 Fibrous dysplasia 14% (185/1319) ML 3 Select Answer to see Preferred Response PREFERRED RESPONSE 2 (OBQ07.42) A 24-year-old male presents with pain in his tibia. Radiographs are shown in Figure A. Histology is shown in Figure B. What is the most likely diagnosis? Review Topic QID: 703 FIGURES: A B 1 Ewing's sarcoma 6% (22/342) 2 Adamantinoma 78% (266/342) 3 Osteosarcoma 7% (25/342) 4 Osteoblastoma 5% (16/342) 5 PNET 3% (11/342) ML 1 Select Answer to see Preferred Response PREFERRED RESPONSE 2 Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK