Bone Tumors & Tumor-like Lesions by Dr. Shahid Manzur

1. Bone tumors and tumor-like lesions: Osteosarcoma, Osteoid
Osteoma, Osteochondroma, and Nonossifying Fibromas
by
DR Shahid Manzur
Associate Proffessor
Department of Diagnostic Radiology
BVH

2. Introduction
• Bone tumors are diverse in their gross
and morphologic features and range
from benign to rapidly fatal. This
diversity makes it critical to accurately
diagnose and stage tumors.
• Timely, accurate diagnosis allows
appropriate treatment so that the
patients can not only survive, but also
maintain optimal function of the
affected body parts.

3. Classification
• Most bone tumors are classified according to the
normal cell or tissue of origin. Lesions that do not
have normal tissue counterparts are grouped
according to their distinct clinicopathologic
features.
• Overall, matrix-producing and fibrous tumors are
the most common. Among the benign tumors,
osteochondroma and fibrous cortical defect are
most frequent. Excluding malignant neoplasms of
marrow origin, osteosarcoma is the most common
primary cancer of bone, followed by
chondrosarcoma and Ewing sarcoma.

4. Epidemiology
• The precise incidence of different bone tumors is
not known because many benign lesions are not
biopsied. Benign tumors outnumber malignant
tumors by at least several hundredfold.
• Benign tumors have their greatest frequency
within the first three decades of life, whereas
malignant tumors are much more common in the
elderly.
• In the United States, about 2,100 new cases of
bone sarcoma are diagnosed annually, and
approximately 1,300 deaths from bone sarcoma
occur each year.

5. Clinical presentation
• Clinically, bone tumors present in various
ways. The more common benign lesions
are frequently asymptomatic and are
detected as incidental findings. Many
tumors, however, produce pain or are
noticed as a slow-growing mass.
Sometimes, the first hint of a tumor's
presence is a sudden pathologic fracture.

6. • Radiographic analysis plays an
important role in diagnosing bone
tumors. In addition to providing
the exact location and extent of
the tumor, imaging studies can
detect features that help limit the
differential diagnosis and give
clues to the aggressiveness of the
tumor. Ultimately, in most
instances, biopsy and histologic
study are necessary.
Diagnosis

7. Osteosarcoma
• Osteosarcoma is defined as a malignant
mesenchymal tumor in which the cancerous cells
produce bone matrix. Osteosarcomas occur in all
age groups but have a bimodal age distribution;
75% occur in patients younger than age 20.
• In adolescence, and about half of them arise in the
metaphysis around the knee, either in the distal
femur or proximal tibia. These are the sites of
greatest skeletal growth activity. In persons over
age 25, the incidence in flat bones and long bones
is almost equal.

8. Major sites of origin of osteosarcomas. The
numbers are approximate percentages.

9. Osteosarcoma
• Osteosarcomas typically present
as painful and progressively
enlarging masses. Sometimes a
sudden fracture of the bone is
the first symptom.
• Grossly, osteosarcomas are
bulky tumors that are gritty,
gray-white, and often contain
areas of hemorrhage and cystic
degeneration. The formation of
bone by the tumor cells is
characteristic of osteosarcoma.
Osteosarcoma of the upper end of the
tibia. The tan-white tumor fills most of
the medullary cavity of the metaphysis
and proximal diaphysis. It has infiltrated
through the cortex, lifted the periosteum,
and formed soft tissue masses on both
sides of the bone.

10. Osteosarcoma
• Radiographs of the primary
tumor usually show a large,
destructive, mixed lytic and
blastic mass. The tumor
frequently breaks through the
cortex and lifts the periosteum,
resulting in reactive periosteal
bone formation. The triangular
shadow between the cortex and
raised ends of periosteum is
known radiographically as
Codman triangle and is
characteristic, but not
diagnostic of this tumor.
Distal femoral osteosarcoma with prominent bone formation
extending into the soft tissues. The periosteum, which has
been lifted, has laid down a proximal triangular shell of
reactive bone known as a Codman triangle (arrow).

11. Central osteosarcoma. A, A destructive lesion is seen in the metaphysis on this anteroposterior view of the
knee in a young teenager with pain. B, A magnetic resonance scan of both legs shows the soft tissue extent
of the tumor (arrows).
Osteosarcoma

12. Osteoid Osteoma
• Osteoid osteomas are bone tumors less than 2 cm
in greatest dimension and usually occur in patients
in their teens and twenties. In fact, 75% of patients
are under age 25.
• Osteoid osteomas can arise in any bone but have a
predilection for the appendicular skeleton. 50% of
cases involve the femur or tibia, where they
commonly arise in the cortex.
• Osteoid osteomas are painful lesions. The pain is
caused by excess prostaglandin E2 which is
produced by the proliferating osteoblasts. It
characteristically occurs at night and is
dramatically relieved by aspirin.

13. Osteoid Osteoma
• Osteoid osteoma. A
lateral view (A) of the
proximal tibia shows a
very dense lesion in the
posterior cortex. A darker
central area contains a
white nidus. This lesion in
a 20-year-old man caused
pain in this area, relieved
by aspirin. B, A nuclear
medicine bone scan in a
different patient with an
osteoid osteoma in the left
lower tibia shows
increased activity (arrows)
at the site of the lesion.

14. Osteoid Osteoma
• Osteoid osteomas,
especially those that arise
beneath the periosteum,
usually elicit a tremendous
amount of reactive bone
formation that encircles
the lesion. The actual
tumor, known as the
nidus, manifests
radiographically as a small
round lucency that is
variably mineralized
Specimen radiograph of intracortical osteoid
osteoma. The round radiolucency with central
mineralization represents the lesion and is
surrounded by abundant reactive bone that
has massively thickened the cortex.

15. Osteoid Osteoma
• Osteoid osteomas’ are considered benign
and are normally treated by conservative
surgery. However there is a possibility of
malignant transformation. This is rare
except when treated with radiation, which
promotes this complication.

16. Osteochondroma
• Osteochondroma, also known as an exostosis, is a
benign cartilage-capped outgrowth that is attached
to the underlying skeleton by a bony stalk. It is a
relatively common lesion and can be solitary or
multiple.
• Multiple osteochondromas become apparent
during childhood but solitary osteochondromas are
usually not diagnosed until late adolescence .
• Men are affected 3X more often than women.
• They arise from the metaphysis near the growth
plate of long tubular bones, especially the knee.

17. Osteochondroma
• Clinically,
osteochondromas present
as slow-growing masses,
which can be painful if
they impinge on a nerve or
if the stalk is fractured. In
many cases, they are
detected as an incidental
finding.
Osteochondroma. On this lateral view of the ankle, a
benign osteochondroma is seen projecting posteriorly
on a stalk. The end (arrows) is often covered with a
cartilaginous cap. These lesions always occur near a
joint but point away from it.

18. Fibrous Cortical Defect and
Nonossifying Fibroma
• Fibrous cortical defects are extremely common,
found in 30% to 50% of all children older than age
2 years. They are believed to be developmental
defects rather than neoplasms.
• The vast majority arise in the metaphysis of the
distal femur and proximal tibia, and almost one
half are bilateral or multiple.
• Fibrous cortical defects are small and those that
grow to 5 or 6 cm in size are called nonossifying
fibromas.

19. Fibrous Cortical Defect and
Nonossifying Fibroma
• Fibrous cortical defects are asymptomatic and are
usually detected on x-ray as an incidental finding.
The vast majority have limited growth potential
and undergo spontaneous resolution within several
years.
• The few that progressively enlarge into
nonossifying fibromas usually show up in
adolescence. They may present with pathologic
fracture and then require biopsy to exclude other
types of tumors.

20. Fibrous Cortical Defect and
Nonossifying Fibroma
• Both fibrous cortical
defects and nonossifying
fibromas produce
elongated, sharply
demarcated radiolucencies
that are surrounded by a
thin zone of sclerosis.
Nonossifying fibromas of the distal tibial
metaphysis, producing an eccentric lobulated
radiolucency surrounded by a sclerotic margin.