Summary
Description
A solitary area of mature, lamellar bone located within another bone, usually within an area of cancellous bone.
Symptoms and Presentation
Patients are generally asymptomatic. These lesions are typically incidental finding on x-ray or other imaging study made for an unrelated reason.
Brief description of the xray
Most are 1 - 2 mm is size, but some can be up to 1 -2 cm. or even more. The lesion is latent, and merges at its margin with the surrounding bone. May be multiple, as in osteopoikilosis.
Brief desc of tx
No treatment is needed. After the diagnosis has been confirmed, the lesion can be observed without treatment.
Tumor Name
Tumor Type
Benign or Malignant
Body region
Most Common Bones
Location in bone
Periosteal reaction
Position within the bone
Tumor behavior
Tumor density
Complete Information on this Tumor
Introduction and Definition
Bone island is also called solitary enostosis. The lesion is a hamartoma, consisting of normal tissue in an abnormal location. It appears as a solitary area of mature, lamellar bone located within another bone, usually within an area of cancellous bone.
X-Ray Appearance and Advanced Imaging Findings
Most are 1 - 2 mm is size, but some can be up to 1 -2 cm. or even more. The lesion is latent, and merges at its margin with the surrounding bone. May be multiple, as in osteopoikilosis. Uptake on bone scan is decreased. MRI and CT scans show that the lesion has identical signal intensity and density to cortical bone, allowing the diagnosis to be made without biopsy.
MRI Findings
Cortical bone is dark on MRI sequences. These lesions should be appear identical to nearby cortical bone on all MRI sequences.
CT Findings
The appearance is similar to nearby cortical bone. There is typically no reaction. The lesions are usually rounded.
Differential Diagnosis
The differential diagnosis includes osteosarcoma, metastasis from prostate cancer or other adenocarcinoma that can cause blastic lesions, and herniation pit/ganglion cyst/old fracture type lesions.
Preferred Biopsy Technique for this Tumor
Biopsy is typically not needed.
Histopathology findings
Normal, mature, lamellar bone with normal architecture, and no cartilage formation or enchondral ossification.
Treatment Options for this Tumor
No treatment is needed. After the diagnosis has been confirmed, the lesion can be observed without treatment.
