0 Epiphyseal lesion should suggest giant cell bone tumor in an adult patient, whereas epiphyseal lesion should suggest chondroblastoma in a patient who has not yet completed skeletal system maturation.
0 Ewing sarcoma, osteomyelitis, osteoid osteoma, osteoblastoma, histiocytosis, lymphoma, fibrous dysplasia and adamantinoma should be kept in mind in diaphyseal lesions.
0 Metastasis, myeloma and hemangioma in vertebral lesions in adult patients, chordoma in the sacrum and giant cell bone tumor should be considered.
0 In young patients, if there is a lesion in the vertebral body, histiocytosis, if there is involvement in the posterior elements of the vertebra, aneurysmal bone cyst, osteoblastoma and osteoid osteoma should be considered in the differential diagnosis.
Benign Bone Tumors and Non-Neoplasmic Conditions
Bone-forming tumors
Osteoid osteoma
It occurs in 2-3 decades and is 3 times more common in males.
Long bones in lower extremity hold posterior elements in spina.
It affects the diaphysis and metaphysis.
There is pain that responds to non-steroidal anti-inflammatory drugs that worsens at night. Increased cyclooxygenase and prostaglandin levels were detected in the lesions. This may explain the relief of severe pain with NSAIDs.
It is characterized by the formation of a radiolucency nidus smaller than 1.5 cm on imaging.
Histology includes trabeculae surrounded by loose fibrovascular tissue.
Bone island (enostosis)
Also called enostosis.
Occurs in adults.
Male to female ratio is equal.
It is usually asymptomatic.
Radiologically, small round areas of increased density and spicules extending to the periphery are seen in the cancellous bone.
The rare condition of multiple bone islands is called osteopoikilosis.
It must be followed up
Cartilage Structures
Chondroma
(the most common)
They are benign lesions of hyaline cartilage. The phalanx is the most commonly affected area. It is the most common tumor of the small bones of the hand and foot.
They are mostly asymptomatic and detected incidentally.
They are also called enchondroma because they mostly originate from the medullary canal.
Multiple enchondromatosis is known as Ollier's disease.
In the presence of soft tissue origin hemangiomas, it is called Mafucci syndrome.
In 25% of Ollier patients, the lesions show sarcomatous changes after the age of 40.
It is characterized by radiologically irregular calcifications. This image is described as a mottled, punctate, or popcorn appearance.
Osteochondroma
They are common benign bone tumors.
There are those who define it as a developmental malformation.
The lesion is characterized by a bony mass, usually stemmed, as a result of progressive endochondral ossification.
It has a cartilaginous head.
After completing the skeletal system maturation, growth usually ends.
They occur most frequently in the distal femur, proximal tibia and proximal humerus.
They are usually asymptomatic and detected incidentally.
Malignant degeneration is extremely rare.
Fibrous lesions
Nonossifying fibroma
Also known as metaphyseal fibrous defect, fibrous cortical defect and fibroxanthoma.
It is a common developmental anomaly seen in 35% of children.
They are detected randomly.
They involve especially distal femur, tibia and fibula between 2-20 years of age.
They appear as well-circumscribed lobulated lesions on direct radiographs.
They are mostly asymptomatic.
Cortical Desmoid
They are irregularities seen in the posteromedial distal femoral metaphysis, usually in males aged 10-15 years.
It is thought to be a stress lesion caused by the pulling force of the adductor magnus muscle.
The lesion can be seen with an oblique radiograph taken with 20-45 degrees external rotation of the lower extremity.
It can cause soft tissue swelling and pain.
Generally followed.
Benign Fibrous Histiocytoma
They are rare lesions that appear mostly in soft tissue and less frequently in bone.
They occur in the diaphysis or epiphysis of the long bone and pelvis.
They are generally seen between the ages of 30-40.
It is characterized by well-circumscribed lytic lesions on radiographs.
Extended curettage or resection is recommended as local recurrence is seen.
Fibrous Dysplasia
They are developmental anomalies that can be monostotic or polyostotic.
Replacement of normal bone and bone marrow with fibrous tissue and small bone spicules is typical.
McCune Albright syndrome has polyostotic fibrous dysplasia, skin pigmentation and endocrine anomalies.
In Mazabraud syndrome, there are polyostotic fibrous dysplasia and intramuscular myxomas.
Radiologically, sclerotic ground-glass appearance with borders is typical.
In the presence of severe pain, pathological fracture or significant deformity, surgical treatment is recommended.
cystic lesions
Unicameral bone cyst
It is one of the common lesions of childhood.
They are considered developmental or reactive lesions rather than true tumors.
85% occur in the first two decades.
They are most common in the proximal humerus and femur.
Lesions enlarge when the skeletal system is in development and heal spontaneously when maturation is completed.
Small asymptomatic lesions can be followed by serial radiographs.
Large lesions that pose a risk for pathological fracture, symptomatic ones are treated surgically.
Aneurysmal Bone Cyst
Local destructive blood-filled reactive bone lesions that are not considered true neoplasms.
It primarily involves the proximal humerus, distal femur, proximal tiba and spine.
Usually lesions appear before the age of 20.
They appear radiologically as an expansile lytic lesion that elevates the periosteum.
This image may be confused with malignancies.
They are treated surgically.
Benign/Aggressive Tumors of Bone
0 While there are completely benign tumors among the tumors described here, there are also overt malignant ones.
0 While most of them can be treated with intralesional treatments, there are also those that require aggressive resection.
0 Giant cell bone tumor and chondroblastoma can develop pulmonary metastases and in rare cases are fatal.
Giant Cell Bone Tumor
• Tumors seen in mild female predominance between the ages of 20-40. The most common sites are the distal femur, proximal tibi, and distal radius. They constitute 5% of all bone tumors. It is mostly a single focus. Pulmonary metastases are present in 3% of cases. The mortality rate due to pulmonary metastasis is 15%.
• Malignant giant cell bone tumors account for less than 5% of cases.
• Most patients have progressive pain. Radiologically, lytic lesions located in the epiphysis of long bones, especially in the subchondral bone, are typical. These tumors are often locally aggressive. Recurrence after treatment has been defined between 5-15%. Surgical curettage is performed.
• Zolendronic acid, which inhibits osteoclastic activity and triggers apoptosis of osteoclasts, can be used in patients who are not suitable for surgery. Again, in cases where surgery cannot be performed, the monoclonal antibody Denosumab, which limits osteoclastic activity, has received FDA approval.
Chondroblastoma
• It is seen between the ages of 10-25. It constitutes less than 1% of all bone tumors. in the epiphysis of the long bones . A well-defined appearance in the epiphysis is typical. Surgical curettage is recommended. Less than 1% of cases develop pulmonary metastases and respond to resection.
Chondromyxoid Fibroma
• The proximal tibia is the most common site. The patient comes with pain. Resection is recommended. It is a rare tumor.
Osteoblastoma
• They are mostly located in the spine.
• Pain is usually the first finding.
• Painful scoliosis and neurological deficit may be due to spinal involvement.
• The most common radiological appearance is a bone-forming mass in the posterior part of the spine in a young patient.
• Classical nidus formation is rarer. The nidus here is larger (> 1.5cm) than the nidus seen in osteoid osteoma.
• Surgery is recommended.
Langerhans Cell Histiocytosis
• It is the common name given to a group of diseases. It can hold many systems. Isolated bone lesions are called eosinophilic granulomas.
• Hand-Schüller-Christian disease: Skull involvement + exophthalmos + diabetes insipidus
• Letterer-Siwe disease: fever + lymphadenopathy + hepatosplenomegaly + multiple bone involvement
• The orthopedist is mostly concerned with eosinophilic granulomas in the bone. Pain is its characteristic feature. The most common site is the vertebral corpuscles. After diagnosis with biopsy, isolated disease can be followed. They resorb spontaneously. Other treatment options include corticosteroid injection, radiotherapy, and curettage.
Radiology in Benign Tumors
The transition zone is narrow.
The lesion borders are clear.
There is no Codman triangle.
Periosteal reaction - no onion skin.
There is no soft tissue extension.