A 21-year-old man with left knee pain for one year.
1.The knee Radiographs is normal?
2.Which bone is abnormal?
3.Which of the following best describes the findings?
A. Permeative pattern with subtle periosteal reaction laterally
B. Well-defined lytic lesion with sclerotic margins
C. Pathologic fracture
D. Both A and C
4.What is the most likely diagnosis?
Bone lymphoma 骨淋巴瘤
Eosinophilic granuloma 嗜酸性肉芽肿
5.What is the most common site of primary bone lymphoma?
- Permeative pattern with subtle periosteal reaction laterallyThere is a permeative moth-eaten appearance of the proximal tibia with subtle periosteal reaction.
- Bone lymphomaBone lymphoma is the most likely diagnosis given the permeative infiltrating bone marrow without any extraosseous or cartilaginous matrix.
Findings and Diagnosis
- Initial radiograph demonstrates moth-eaten/permeative appearance of the proximal tibia with underlying areas of sclerosis and ill-defined margins. No pathologic fracture is seen.最初的X线片可见胫骨近端骨质硬化，边界不清，内可见虫蚀样/穿凿样骨质破坏。无明显病理性骨折。
- CT images demonstrate moth-eaten/permeative appearance of the proximal tibia with ill-defined margins and aggressive periosteal reaction.CT示胫骨近端虫蚀样/穿凿样骨质破坏，边界不清，局部可见骨膜反应。
- MRI demonstrates heterogeneously increased T2 and decreased T1 signal involving the proximal left tibia. This is most suggestive of primary bone lymphoma versus primary osseous neoplasm.MRI示左胫骨近端病灶T2WI呈不均匀稍高信号，T1WI呈低信号。在原发性骨骼肿瘤中，首先考虑骨原发性淋巴瘤。
- Primary bone lymphoma骨原发性淋巴瘤
- Metastatic disease转移瘤
- Can occur at any age, peak in fourth and fifth decades.可发生于任何年龄段，尤其是40-50岁。
- Males > females.男性多于女性
- Femur is the most common (25%) site of involvement. Other sites being pelvis, humerus, head and neck, and tibia.最常发生于股骨（25%），其次为骨盆、肱骨、头颈、胫骨。
- Primary lymphoma of bone manifests with insidious and intermittent bone pain present for months.骨原发性淋巴瘤常见症状为隐匿性、间歇性疼痛，病程可达数月。
- Other signs and symptoms include the following: 1.Local swelling；2.Palpable mass；3.Systemic symptoms such as weight loss and fever其他症状包括：1.局部肿胀；2.肿胀；3.全身症状，如体重减轻、发热等。
- Vertebral involvement can cause radicular symptoms and can even lead to compression of the spinal cord.如果发生于椎体，可引起神经根症状，甚至可以压迫脊髓。
- Three patterns:X线/CT表现共包括3型：
1. Near-normal-appearing bone on radiographs with abnormal bone scan and MRI.
2. Focal lytic lesion with geographic margins or diffusely permeative/moth-eaten appearance with cortical destruction and soft-tissue involvement. This can be associated with a sequestrum sometimes, which helps distinguish this from osteosarcoma.
3. Mixed sclerotic-lytic lesion, more common with metastatic bone lymphoma.
- Periosteal reaction is seen in about 60% of cases and is usually aggressive with lamellated or layered appearance, wherein layers of periosteal bone are seen parallel to the long axis of the bone (also called onion-peel appearance), or broken, when discontinuous or interrupted periosteal new bone is seen.约60%的病例可见骨膜反应，多为板状或层状。其中层状骨膜反应多平行于骨骼长轴（又称葱皮样）。骨膜新生骨发生断裂或不连续。
- T1-weighted images: Low signal intensity compared with the normal marrow and lower signal than the muscle.T1WI:与正常骨髓相比呈低信号，低于肌肉信号。
- T2-weighted images: Increased signal with peritumoral edema and extensive marrow disease.T2WI：呈高信号，可见瘤周水肿及广泛的骨髓受侵
- Contrast-enhanced images: Demonstrate areas of enhancement within the lesion.增强扫描：病灶内可见强化。