What is the difference between osteochondroma and osteosarcoma

Based on how the cancer cells look under the microscope, osteosarcomas can be classified as high grade, intermediate grade, or low grade. The grade of the tumor tells doctors how likely it is that the cancer will grow quickly and spread to other parts of the body.

These are the fastest growing types of osteosarcoma. When seen with a microscope, they do not look like normal bone, and many of the cancer cells are in the process of dividing into new cells. Most osteosarcomas that occur in children and teens are high grade. There are many types of high-grade osteosarcomas although the first 3 are the most common.

These uncommon tumors fall between high-grade and low-grade osteosarcomas. They are usually treated the same way as low-grade osteosarcomas.

These are the slowest-growing osteosarcomas. The tumors look more like normal bone and have few dividing cells when seen with a microscope. The grade of the tumor plays a role in determining its stage and the type of treatment used. For more on staging, see Osteosarcoma Stages. Ewing tumors Ewing sarcomas are the second most common bone cancer in children.

They are described in Ewing Family of Tumors. Most other types of bone cancers are usually found in adults and are uncommon in children. These include:. Prior to undergoing HSCT, high-dose chemotherapy and total-body irradiation TBI are administered in an attempt to eradicate residual malignant cells and cure the patient; however, the high-dose chemotherapy and radiotherapy may increase the risk of adverse effects in almost every organ or system in the body.

In particular, the major skeletal complications observed in TBI survivors are osteoporosis, avascular necrosis and benign or malignant bone tumors. Osteochondroma is a benign cartilage-capped tumor that predominantly develops at the juxtaepiphyseal region of the long bones. There have been few reports of osteochondroma as a secondary bone tumor following the treatment of childhood neuroblastoma 2 — 4 ; however, there are considerable experimental and clinical data linking osteochondroma to localized high-dose and TBI 5.

The simultaneous occurrence of osteosarcoma and osteochondroma following treatment of neuroblastoma with chemotherapy, radiotherapy and autologous peripheral HSCT rescue has been reported previously 7. However, the current literature indicates a low incidence of malignant degeneration in radiation-induced osteochondroma 8 — 10 and only one case of chondrosarcoma arising within radiation-induced osteochondroma following childhood TBI has been reported thus far Herein, the present study reports a case of osteosarcoma arising from osteochondroma 11 years after the patient underwent surgery, local irradiation, chemotherapy, TBI and HSCT for neuroblastoma.

Due to the radiographic characteristics and localization of the tumor, it is postulated that the osteosarcoma arose from osteochondroma and developed following TBI. To the best of our knowledge, this is the first reported case of its type. Written informed consent was obtained from the patient's family. A 5-year-old boy was admitted to Niigata University Hospital Niigata, Japan in January with a 2-week history of fever, cough, fatigue, headache and abdominal pain.

On physical examination, a gross abdominal mass was palpable. Abdominal computed tomography CT demonstrated a retroperitoneal mass located adjacent to the left kidney and multiple enlarged lymph nodes along the aorta. The patient underwent an open biopsy, and pathological examination revealed a diagnosis of neuroblastoma, revealing undifferentiated unfavorable histology, DNA diploidy and MYCN oncogene amplification 12 copies. Multiple metastases to the occipital bone, left humerus, left tibia and bone marrow were indicated upon metaiodobenzylguanidine I-MIBG scanning.

On the basis of these findings, the patient was diagnosed with stage IV neuroblastoma and considered to belong to the high-risk group, according to the International Neuroblastoma Staging System Following the diagnosis of neuroblastoma, the patient was treated according to the nationwide standard protocol established by the Japan Study Group for Advanced Neuroblastoma Following completion of these 4 cycles, residual metastatic lesions were identified by performing a CT scan.

Therefore, ifosfamide-based salvage chemotherapy was immediately undertaken, including one cycle of ifosfamide, carboplatin IC and etoposide ICE , containing 4. Following induction chemotherapy, tumor markers were still not normalized VMA, Thus, gross total resection to remove the entire macroscopic tumor from the primary site, including the regional lymph nodes, and combined resection of the left kidney were performed.

This was followed by 12 Gy of intraoperative radiation therapy of the tumor bed and para-aortic lymph nodes. TBI was delivered using 12 Gy radiation in 6 doses of 2-Gy fractions twice-daily for 3 consecutive days. Tumor markers, including serum NSE, and urinary HVA and VMA became normalized and were maintained within the normal ranges immediately after completion of the radiotherapy. At this time, the patient did not have any experience pain or discomfort and did not receive any treatment following this diagnosis.

Physical examination revealed swelling along the distal aspect of the upper left arm, and radiography of the left elbow identified a periosteal reaction in the distal humeral shaft and an associated medial soft-tissue mass Fig.

Subsequent magnetic resonance imaging of the tumor demonstrated an absence of medullary involvement, an irregular cortical surface and a soft-tissue mass Fig. The subperiosteal location of the tumor was clear and the imaging features were typical of osteosarcoma arising from osteochondroma. The remainder of the metastatic work-up, including chest radiography, whole-body CT and h monitoring of urinary VMA, dopamine and catecholamine levels, revealed no abnormalities.

In addition, there was no family history of malignancy. Fine-needle aspiration cytology revealed oval- to spindle-shaped cells, a number of which had a high nucleocytoplasmic ratio with hyperchromatic nuclei, irregular nuclear border and prominent nucleoli. Additionally, osteoblasts with pronounced nuclear atypia were observed and diagnosed as osteosarcoma. Furthermore, severe neuralgic pain in the jaw and abdomen was precipitated by an additional cycle of single agent chemotherapy comprising 2 mg vincristine.

A Anteroposterior and B lateral radiographs captured 11 years after total-body irradiation indicating a poorly defined, broad surface-based lesion arising from the distal shaft of the humerus, with a spiculated and aggressive periosteal reaction perpendicular to the long axis of the humerus. The normal cortex is continuous with the lesion. A Axial T1-weighted magnetic resonance image revealing a circumferential soft tissue mass around the distal shaft of the left humerus, with similar signal intensity to muscle.

B Fat-saturated T2-weighted magnetic resonance image indicating that the soft tissue component around the surface of the bone has low signal intensity due to dense matrix mineralization. The more peripheral component is hyperintense, reflecting the chondroblastic content of this tumor. C Axial and D sagittal post-contrast fat-suppressed T1-weighted magnetic resonance images demonstrating enhancement of the peripheral and a less densely mineralized component of the soft tissue mass.

One month after completion of three cycles of preoperative chemotherapy, the patient underwent wide local excision of the tumor followed by reconstruction with an extracorporeally irradiated autograft combined with an iliac bone graft Fig. All bone segments were administered with a single fraction of 70 Gy of radiation. It arises from metaphysis of long bone of lower extremity, while other sites are uncommon. Radiologically, there are irregularly sclerotic lesions with poorly defined sclerotic margins, and mineralized matrix is common Figure 7A—C.

A Radiological examination showing medullary and cortical bone destruction wide zone of transition ring and arrow , permeative or moth-eaten appearance. Chondroblastoma is a rare primary bone tumor of young people that typically arises at the ends of the long bones.

Radiologic investigations show a small, circumscribed, lytic lesion. The tumor is characterized histologically by the proliferation of chondroblasts along with areas of mature cartilage, giant cells, and, occasionally, secondary aneurysmal bone cyst formation. Chondroblastoma, however, may also present with atypical features, such as prominent hemosiderin deposition, numerous giant cells, or the presence of a large aneurysmal bone cyst component. A rare variant of osteosarcoma with CB features may be seen and can be difficult to distinguish from CB, as both tumors can present in young patients as a lytic lesion in an epiphyseal location.

Histologically, this OS may reveal small round-oval cells with eosinophilic cytoplasm and scattered giant cells and therefore may cause confusion with CB, especially on a small biopsy specimen. It is usually seen in young ages 10? It is commonly found in metaphysis, diaphysis of ribs, jaw, skull, tibia, and femur.

It is locally aggressive tumor and may be monostotic or polyostotic and associated with endocrine disorders. Radiologically, it is circumscribed radiolucent lesions, within the medullary cavity.

There is no cortical destruction on X-rays seen in FD, while there are irregularly sclerotic lesions with poorly defined sclerotic margins. Usually seen in young persons, it is a benign lesion. Microscopically, no osteoid and bony trabeculae but only storiform spindle stroma, giant cells, and hemosiderin-laden microphages are seen.

Radiologically, these are eccentric sharply defined lytic lesions in metaphyseal cortex in young people. This infrequent variant occurs in a juxtacortical position in the metaphyses of long bones and grows very slowly. It grows, as a lobulated mass around the bone shafts as a low-grade malignant bone tumor with well-formed bony trabeculae, osteoid, variable cartilage, and highly fibrous spindle cell stroma in disorganized manner.

In some cases there may be hypocellularity, but there is always mild atypia in the stroma. These tumors have a slight female predominance, with a male-to-female ratio of About three fourths of cases involve the distal posterior femur, with the proximal tibia as the second most common site.

Clinically it presents as a painless mass of long duration; pain may occur late in the course of this tumor but is not evident initially. Microscopically, there is disorderly arrangement of well-formed bony trabeculae and osteoid and exceptionally osteoclast-like giant cells. There are spindle-shaped stroma with mild atypia and variable amount of cartilage Table 9 compared to conventional OS Figure 8 and Table 9.

Radiodense, bosselated, or mushroom-shaped mass arises on the surface of a bone; in long-term lesions, tumor may encircle the bone [ 41 ]. X-ray of parosteal osteosarcoma ring showing surface-attached mass A. It is a benign disorder where the medullary spaces contain adipose tissue or marrow hematopoietic tissue with cartilaginous cap.

The bony trabeculae are normally arranged as compared to the PAOS. There is the dense ossification in the center in MO and opaque bone at the periphery, making it eggshell in appearance. Histologically there is zonal arrangement.

Maturation toward lamellar bone and marrow adipose tissue begins peripherally and extends centrally in this proliferative process, which is the reverse in parosteal osteosarcoma [ 41 ]. The osteochondroma shows continuity of corticomedullary areas of the tumor and the underlying medullary canal, but these features are lacking in PAOS. Medullary spaces contain adipose tissue or marrow hematopoietic tissue, cartilaginous cap.

Abundant cartilage is present. Higher-grade osseous component and evidence of periosteal reaction. This malignant bone tumor is commonly seen in routine biopsies, entirely different from PAOS juxtacortical OS despite its similarity with terminology. It arises on surface of long bones upper tibia and femur. The PEOS affects a slightly older age group 10—20 years as compared to conventional osteosarcoma. Malignant osteoid must be present, but the predominant pattern of tumor is represented by lobulated chondromatous tissue with cytologic features of grade 2 or 3 chondrosarcoma.

Tumor is located on the surface of the bone and may extend into soft tissue. The lesions are limited to the cortex and rarely invade the medullary cavity.

The tumor appears perpendicular to the shaft. Sometimes high-grade anaplastic sarcomatous spindle cell component may separate lobules of the malignant chondroid component [ 24 ] Figure 9 and Table 10 [ 20 , 42 ]. X-ray of periosteal osteosarcoma ring showing broad-based lesion thickening of cortical areas of the femur A. Differential diagnosis of parosteal osteosarcoma, conventional osteosarcoma, periosteal osteosarcoma, osteochondroma, myositis ossificans, and parosteal lipoma.

Differential diagnosis of WD intramedullary osteosarcoma, parosteal osteosarcoma, conventional OS, periosteal osteosarcoma, and fibrous dysplasia. It is usually smaller and better defined and composed of benign chondroid tissue and does not contain malignant tumor osteoid [ 24 ]. Radiographically, this tumor is more radiodense, and histologically this is a low-grade malignant fibro-osseous tumor without chondroid differentiation [ 20 , 24 ].

This is a higher-grade osteosarcoma involving the medullary cavity. Periosteal osteosarcoma does not involve the medullary cavity [ 24 ]. It lacks cartilaginous differentiation. Osteoid component is pleomorphic and high grade [ 12 , 13 ]. This is a high-grade osteosarcoma with similar histological features to those of conventional intramedullary osteosarcoma.

The tumor grows on the surface and lacks significant medullary involvement. Radiographically it mimics periosteal osteosarcoma, except it has cumulus cloud-like patterns of mineralization.

It is a large, lobulated surface mass with variable consistency ranging from soft to firm and may contain hemorrhagic areas. It should not significantly involve the medullary region [ 13 , 24 ]. It usually has residual low-grade malignant fibroblastic stromal component. Parosteal osteosarcoma lacks high-grade anaplastic appearance [ 12 , 24 ].

Significant medullary component minimal medullary component in a high-grade surface osteosarcoma [ 24 ]. It is a large, poorly marginated intramedullary mass that either is sclerotic or exhibits trabeculations and histologically similar to parosteal osteosarcoma [ 12 , 24 ]. Osteosarcoma OS is a high-grade malignancy of the bone with high-mortality rate. The exact cause of the condition is unknown, and presently, it is not possible to prevent an osteosarcoma occurrence.

It is mainly divided into two types, primary and secondary, based on etiology, while based on where they occur, osteosarcoma is classified as medullary osteosarcoma occurring in the bone cavity and surface osteosarcoma occurring on the bone surface. OS has a bimodal age distribution, having the first peak during adolescence and the second peak in older adulthood, while a little bit more common in males.

Some genetic mutations, like mutation of RB and P53 genes, are associated with osteosarcoma. The tumor grows slowly in the initial phase of the tumors and may be asymptomatic. Then tumors grow at a moderate rate, and then they suddenly start to rapidly progress. Pathological fractures are commonly seen in long bones. Three parameters are used for its diagnosis, physical examination with medical history, radiological support X-rays, CT, MRI , and biopsy for microscopic examination. To approach the remedy of patient, grading and staging with good differential diagnosis are very important to save the life of the patient.

Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution 3. Help us write another book on this subject and reach those readers. Login to your personal dashboard for more detailed statistics on your publications. Edited by Matthew Gregory Cable. Edited by Kanya Honoki. We are IntechOpen, the world's leading publisher of Open Access books. Built by scientists, for scientists.

Our readership spans scientists, professors, researchers, librarians, and students, as well as business professionals. Downloaded: Abstract Primary bone tumors are rare, but osteosarcoma OS is the fourth commonest non-hematological primary neoplasm of the bone in the adolescence, and the other three commonest neoplasms, in descending order, are leukemia, brain tumors, and lymphoma.

Keywords aggressive osteoblastoma osteogenic tumors osteoma osteoid osteoma osteoblastoma osteogenic sarcoma. Introduction Primary neoplasm of the bones is relatively uncommon. Table 1. WHO-based classification of osteogenic tumors of the bone. Appears to be attached to the surface of the parent none Histology Nodular or dome-shaped, dense cortical bone Consists of dense lamellar bone with or without Haversian canals and usually without a medullary component Medullary component consists of hematopoietic or fibroadipose tissue Regular large ossicles of mature bone Lamellar bone with prominent osteoblastic rimming Osteoma may have focal areas of reactive bone with similar features but not cellular as compard to OO, see also Table 3 The stroma is fibrous and more cellular Small ossicles and irregular bony trabeculae, much less mature bone Psammoma bodies Tumor osteoid is arranged in parallel arrays and separated by a bland fibroblastic stroma.

With minimal atypia. Cartilage may be seen. See also Table 9 No other benign lesions seen See Table 9. Table 2. Appears to be attached to the surface of the parent noneMRI and CT are more helpful Histology Irregular trabeculae of lamellar bone with prominent osteoblastic rimming Loose fibrovascular stroma See also Table 2 No central nidus Presence of neutrophils, lymphocytes, macrophages, etc.

No central maturation like nudus Intralesional hemorrhages like ABC and numerous osteoclast-like giant cells No peripheral rim of fibrovascular tissue like in nidus Epithelioid aggressive variant with large atypical epithelioid like osteoblasts may confuse with OS, but take guidance from radiology.

See Tables 2 and 4 The stroma is fibrous and more cellular Small ossicles and irregular boneTrabeculae, much less mature bonePsammoma bodies Tumor osteoid is arranged in parallel arrays and separated by a hypocellular fibroblastic stroma The spindle cells between bony trabeculae instead of fat and hematopoietic tissue as seen in OSLacks the fibrovascular stroma and osteoblastic rimming of osteoid osteomaMay show cartilage component.

See Tables 4 — 8 for IHC. Table 3. No central maturation like nidus Intralesional hemorrhages like ABC and numerous osteoclast-like giant cells No peripheral rim of fibrovascular tissue like in nidus Irregular trabeculae of lamellar bone with prominent osteoblastic rimming Loose fibrovascular stroma Tumor osteoid is arranged in parallel arrays and separated by a hypocellular fibroblastic stroma.

Atypia is common The spindle cells between bony trabeculae instead of fat and hematopoietic tissue as seen in OS Lacks the fibrovascular stroma and osteoblastic rimming of osteoid osteoma May show cartilage component Sheets of giant cells and more in number and contain more nuclei Giant cell tumors contain mononuclear stromal cells Small foci of reactive osteoid may be present in aneurysmal bone cysts, which should not be confused with osteoblastoma.

Table 4. No bone matrix is radiographically identified Onion skin appearance in ES on radiology Soap bubble appearance Sharp and lytic lesions Fine calcification Histology Tumor osteoid is arranged in parallel arrays and separated by a hypocellular osteoblastic stroma. Atypia and mitosis are commonThe small cells between bony osteoid. Table 5. An effusion may be seen in an adjacent joint. MRI is more helpful Multiple lytic lesions with significant periosteal reaction The conventional radiographs show ground glass appearance with no associated soft tissue mass.

There are generally no aggressive radiographical features Histology Tumor osteoid is arranged in parallel arrays and separated by a hypocellular fibroblastic stroma. Atypia is common The spindle cells between bony trabeculae instead of fat and hematopoietic tissue as seen in OS Lacks the fibrovascular stroma and osteoblastic rimming of osteoid osteoma May show cartilage component In acute cases, neutrophils and necrotic bony trabeculae, in TB, granulomas, and in chronic nonspecific cases, lymphocytes and macrophages are more common There is monoclonal proliferation of Langerhans cells distinctive cells of monocyte—macrophage lineage and should be considered a malignancy although its biological behavior is very variable.

EM shows Birbeck granules. Table 6. Sometimes, may appear with blood-filled spaces. Table 7. Atypia is common The spindle cells between bony trabeculae instead of fat and hematopoietic tissue as seen in OS Lacks the fibrovascular stroma and osteoblastic rimming of osteoid osteoma May show cartilage component No extensive osteoid formation. Some osteoid osteogenic sarcomas may have a predominant histologic pattern of malignant fibrous histiocytoma; the presence of osteoid formation requires the diagnosis of osteosarcoma They are heterogeneous fibroblastic tumors formed by poorly differentiated fibroblasts, myofibroblasts, histiocyte-like cells with high degree of pleomorphism and characteristic storiform pattern and also demonstrating bizarre multinucleated giant cells Run-X-2 negative DLBCL is the most common subtype.

The bony pelvis and femur are the most common locations They manufacture abundant osteoid, but they are not composed of atypical and pleomorphic osteoblasts.

Table 8. There are irregularly shaped bony trabeculae without rimming of osteoblasts. Cortex and medulla are continuous with underlying bone Lytic lesions without bony destructions Histology Tumor osteoid is arranged in parallel arrays and separated by a hypocellular fibroblastic stroma that exhibits minimal cytologic atypia and minimal mitotic activity without atypical forms This is a higher-grade osteosarcoma involving the medullary cavity.

Periosteal osteosarcoma does not involve the medullary cavity Osteosarcoma with prominent cartilaginous component.