Osteochondroma
Osteochondromas are the most common benign bone neoplasms.
They are usually diagnosed in the early adulthood.
They are mainly asymptomatic,
but sometimes may present with osseous deformation,
fractures,
bursitis and neurovascular compromise.
Osteochondromas are typically located on metaphyseal regions of long tubular bones,
scapula or ilium.
Osteochondromas can be pedunculated or sessile bone protrusions with continuity to the bone and a cartilage cap adjacent to it,
which is variable in appearance.
Osteochondromas presents on plain radiography and on CT as a well-circumscribed protuberance with cortical and medullar continuity with underlying bone.
MRI allows the assessment of the hyaline cartilage cap,
the oedema and the neurovascular structures.
The cartilage cap will show low SI with T1-weighting and high SI with T2-weighting.
The differential diagnoses include parosteal osteosarcoma,
periosteal chondroma and chondrosarcoma.
Enchondroma
Enchondroma are common benign bone neoplasms,
affecting intramedullary cartilage.
They are usually diagnosed between childhood and early adulthood.
Enchondromas are mainly asymptomatic,
but sometimes may present with pain from pathological fracture.
These lesions are usually solitary but can be multiple as a manifestation of a genetic syndrome like Ollier and Maffucci syndromes,
which have a high potential of malignancy.
Enchondromas are typically located in a central or eccentric position within the medullary cavity of tubular bones,
mainly hands and feet,
especial the proximal phalanx but also in large tubular bones like the femur and tibia.
They arise more frequently from the metaphyseal region.Enchondromas presents on plain radiography as a small well-circumscribed geographic lytic lesion,
who can present chondroid calcifications.
CT is better to assess cortical integrity and matrix calcifications than radiographs.
MRI will show a lobular architecture,
a variable SI on T1-weighted imaging,
high SI on T2-weighted imaging and the rings-and-arcs pattern of enhancement.
The differential diagnosis includes bone infarct,
intraosseous ganglion,
lytic metastasis to bone,
granulomatous disease and chondrosarcoma,
in which cases is very important to exclude periosteal reaction and a soft tissue mass.
Chondroblastoma
Chondroblastoma are a rare benign cartilaginous tumor.
They arise mostly in the epiphysis of young patients.
They have non-specific clinical manifestations,
such as joint pain,
tenderness and a local mass.
The chondroblastoma are typically located in the long bones,
mainly in the humerus,
femur and tibia.
They are located eccentrically within the epiphysis and may extend into the metaphysis.
Chondroblastoma shows on plain radiography geographic lytic lesion with a thin sclerotic rim.
They can present with a variable degree of internal calcifications.
CT demonstrates a thick periosteal reaction along the metaphysis,
internal calcifications and sometimes endosteal scalloping.
MRI show the periosteal reaction in the metaphyseal region,
but also tissue edema.
It will show low variable SI with T1-weighting and variable high SI with T2-weighting,
often in a lobulated pattern.
The differential diagnoses include giant cell tumor,
osteomyelitis and clear cell chondrosarcoma.
Chondromyxoid fibroma
Chondromyxoid fibroma are a extremely rare benign cartilaginous tumor.
They arise mostly in the metaphyseal region of long bones of adult patients,
mainly tibia and femur.
They may extend to epiphyseal line.
The patients present with progressive pain,
bone swelling and a restricted range of movements.
Chondromyxoid fibroma shows on plain radiography lobulated eccentric lytic lesions,
with sclerotic margins,
no periosteal reaction,
geographic bone destruction e perilesional sclerosis.
MRI show low SI with T1-weighting and variable high SI with T2-weighting,
often in a lobulated pattern.
The differential diagnoses include giant cell tumor,
aneurysmal bone cyst,
chondroblastoma and non-ossifying fibroma.
Chondrosarcoma
Chondrosarcoma are common malignant cartilaginous tumor.
They affect mostly older patients and can arise primarily or secondary to a previous benign cartilage neoplasm.
Chondrosarcoma can be divided into several categories: conventional intramedullary chondrosarcoma,
justacortical chondrosarcoma,
clear cell chondrosarcoma,
myxoid chondrosarcoma,
mesenchymal chondrosarcoma and dedifferentiated chondrosarcoma.
Secondary chondrosarcoma is subdivided into central (related to enchondroma) and peripheral (related to osteochondroma) types.
Patients presents with pain,
pathological fractures and a palpable lump.
Chondrosarcomas are typically located in the long bones,
mainly in the femur and humerus but also in the pelvis.
femur and tibia.
Chondrosarcoma shows on plain radiography lytic lesions,
intralesional calcifications,
endosteal scalloping,
permeative appearance and a cortical remodelling,
thickening and periosteal reaction.
CT demonstrates matrix calcification,
endosteal scalloping,
cortical breach,
soft tissue mass and a heterogeneous contrast enhancement.
MRI show iso to hyperintense SI with T1-weighting and high SI with T2-weighting,
in calcified portions.
The differential diagnoses include enchondroma,
metastasis,
malignant fibrous histiocytoma,
fibrosarcoma or lytic secondary osteosarcoma.