Summary
Description
Periosteal chondroma is a benign cartilage tumor that occurs on the surface of the bones, under the periosteum.
People and Age
This tumor may occur in both children and adults.
Symptoms and Presentation
Patients complain of a tender swelling or mass.
Brief description of the xray
A lesion on the surface of the bone with cartilage matrix, which may "ring and arc" or "popcorn" calcification pattern. The tumor causes the underlying bone to become sclerotic, and there may be a "dished" area under the tumor, and a "buttress" or peripheral wall of reactive bone at the edge of the tumor. The cortex may be abnormal or locally thinned adjacent to the tumor.
Brief desc of tx
Simple excision of this tumor usually results in a cure.
Tumor Name
Tumor Type
Benign or Malignant
Body region
Most Common Bones
Location in bone
Position within the bone
Tumor behavior
Tumor density
Complete Information on this Tumor
Introduction and Definition
Juxtacortical chondroma (synonym: periosteal chondroma) is a rare benign surface lesion composed of cartilage. It is similar in appearance and location to periosteal osteosarcoma. The potential for confusion with periosteal and even parosteal osteosarcoma mandates a thorough investigation and biopsy of these lesions.
Incidence and Demographics
In one series this tumor accounted for 2/300 tumors, 0.66%. Age range is 1 to 73 years, with peak age at diagnosis in the 2nd or 3rd decade. Males are affected 2:1 over females. Symptoms are present for 1 to 5 years. Common sites include the proximal humerus, proximal and distal femur, and the phalages of the hand and foot.
Symptoms and Presentation
Symptoms are present for 1 to 5 years. Patients complain of a tender swelling or mass.
X-Ray Appearance and Advanced Imaging Findings
Radiographically the lesion has its epicenter in the region of the outer cortical surface of the bone. There is no stalk or peduncle as in an osteochondroma. The most common location is adjacent to the metaphysis.
The cortex may be involved to a variable degree, but the lesions do not involve the medullary space. There is a mass outside the confines of the bone that contains amorphous ossification. In the cases of this lesion the author has seen, there were no ring and arc figures seen in the ossified matrix, and neither was there any trace of trabecular organization of the ossified material. Reports indicate that 1/3 of these lesions have matrix calcification.
There is no periosteal reaction, but the lesion may lift the periosteum and create "columns" or "buttresses" of mature periosteum at each end of the mass that appear to project out from the axis of the bone. Pressure from growth of the lesion may create a "dish", "cup" or "saucer" shaped defect, or a complex shaped defect in the underlying bone. The lesion itself may have a thin cortical shell and /or internal calcifications with a ring, arc, or popcorn pattern characteristic of cartilage. Phalangeal lesions are most likely to have matrix calcifications, according to the AFIP.
Laboratory exam will help only in confirming that there is no systemic condition such as infection.
Bone scan will show that the lesion is actively making bone, and is only helpful to count lesions.
CT scan shows a more precise picture of the lesion and its juxtacortical location. It may reveal the amorphous character of the ossific material within the lesion, as well as help in distinguishing the tumor from osteochondroma, osteoid osteoma, and myositis ossificans, but not from periosteal osteosarcoma and parosteal osteosarcoma. CT should be done even if an MRI has been done.
MRI is not likely to be of much additional value after CT. If doubt exists about the nature of the tissue in the lesion the MRI may help identify the cartilage component.
The cortex may be involved to a variable degree, but the lesions do not involve the medullary space. There is a mass outside the confines of the bone that contains amorphous ossification. In the cases of this lesion the author has seen, there were no ring and arc figures seen in the ossified matrix, and neither was there any trace of trabecular organization of the ossified material. Reports indicate that 1/3 of these lesions have matrix calcification.
There is no periosteal reaction, but the lesion may lift the periosteum and create "columns" or "buttresses" of mature periosteum at each end of the mass that appear to project out from the axis of the bone. Pressure from growth of the lesion may create a "dish", "cup" or "saucer" shaped defect, or a complex shaped defect in the underlying bone. The lesion itself may have a thin cortical shell and /or internal calcifications with a ring, arc, or popcorn pattern characteristic of cartilage. Phalangeal lesions are most likely to have matrix calcifications, according to the AFIP.
Laboratory exam will help only in confirming that there is no systemic condition such as infection.
Bone scan will show that the lesion is actively making bone, and is only helpful to count lesions.
CT scan shows a more precise picture of the lesion and its juxtacortical location. It may reveal the amorphous character of the ossific material within the lesion, as well as help in distinguishing the tumor from osteochondroma, osteoid osteoma, and myositis ossificans, but not from periosteal osteosarcoma and parosteal osteosarcoma. CT should be done even if an MRI has been done.
MRI is not likely to be of much additional value after CT. If doubt exists about the nature of the tissue in the lesion the MRI may help identify the cartilage component.
MRI Findings
MRI signal features typical of cartilage are seen, dark on T1 and very bright on T2. Larger lesions may have a slight granular or lobular appearance.
CT Findings
The underlying "dish", "cup" or "saucer" shaped defect formed by the lesion, and the "buttresses" adjacent to it may be better seen on properly oriented CT scans.
Differential Diagnosis
To differential the lesion from the surface osteosarcomas, look for a mass of very heavily ossified tumor bone plastered in the surface of the bone. Periosteal osetosarcoma tends to be more diaphyseal, a little less ossified, and has a more rapid growth pattern as compared to juxtacortical chondroma. Some of these lesions have a more "classic" xray appearance and can be treated without a seperate biopsy step. In lesions without classic features, making a call of juxtacortical chondroma based on imaging alone would not be recommended.
Preferred Biopsy Technique for this Tumor
open
Histopathology findings
On gross pathology, the lesion consists of cartilage and ossified cartilage. On microscopic exam there is benign cartilage with typical chondrocytes in scattered lacunae and noneoplastic bone being formed by enchondral ossification. There is no neoplastic cartilage with hypercellularity or bizarre chondrocytes, and no neoplastic osteoid or bone as in periosteal osteosarcoma.
Treatment Options for this Tumor
complete excision by curettage is curative
Preferred Margin for this Tumor
intrlesional
Outcomes of Treatment and Prognosis
Recurrence following removal is unlikely.
