Bone Aneurysmal Cyst

Bone Aneurysmal Cyst

Aneurysmal Bone Cyst

Aneurysmal bone cyst (AOC) belongs to the group of pseudotumor bone lesions. This group of diseases produces bone changes that mimic tumor lesions, from the point of view of radiographic imaging.

Aneurysmal Bone Cyst

The injuries that are part of this group are:

simple bone cyst.

aneurysmal bone cyst.

juxtacortical bone cyst (intraosseous ganglion).

metaphyseal fibrous defect (non-ossifying fibroma).

eosinophilic granuloma.

fibrous dysplasia (osteofibrodysplasia).

myositis ossificans.

brown tumor of hyperparathyroidism.

intraosseous epidermoid cyst.

giant cell reparative granuloma.

The aneurysmal bone cyst, also called multilocular hematic cyst, is a lesion of insufflative bone rarefaction filled with serosanguineous fluid, interspersed with spaces varying in size and separated by septa of connective tissue containing trabeculae of bone or osteoid tissue and ostoclastic giant cells (fig 1 ).

Figura 1 - C.O.A. múltiplos septos de tecido conjuntivo
Figure 1 - COA multiple connective tissue septa

The origin and etiology of this process are still unknown, despite having been described by Jaffe and Lichtenstein since 1942. Cytogenetic studies suggest that there is a correlation between this lesion and chromosome 17 translocation phenomena.

The presence of osteoclast-type giant cells suggests that a process of localized bone reabsorption occurred, accompanied by accumulation of blood and septated either by connective tissue or by osteoid tissue with bone trabeculae.

These blood-filled cavities do not have blood supply that can be demonstrated by arteriography or intracystic contrast infusion and consequently do not have a pulsatile character. These pockets are not empty therefore they are not cysts nor do they represent any form of aneurysm. The term “aneurysmal bone cyst” is not appropriate for this condition.

It is therefore a benign lesion and according to Enneking it can be classified as active or aggressive benign. The presence of areas of fibrosis and reparative ossification is related to cyst regression or the result of a previous fracture (fig 2).

Figura 2 - Rm. axial T1. cisto ósseo aneurismático da tíbia.
Figure 2 - Rm. axial T1. aneurysmal bone cyst of the tibia.

The stores occur in varying numbers and sizes, clumping together and causing erosion of the bone trabeculae, which expand and inflate the cortex. Histologically, blood gaps are observed separated from each other by connective septa and osteoclastic cells, without atypia.

However, this “phenomenon” of an aneurysmal bone cyst may appear alongside other tumor lesions such as osteoblastoma   chondroblastoma  ,   chondromyxoid fibroma,  giant  cell tumor, teleangiectatic  osteosarcoma,   fibrous  dysplasia  and brown  tumor of hyperparathyroidism , in addition to metastatic lesions secondary to  thyroid  or  kidney neoplasia . These tumors with their characteristic histology may present isolated areas of the classic aneurysmal bone cyst. Therefore, small biopsy fragments can make accurate diagnosis difficult (fig 3).

Figura 3: Tumor de células gigantes do fêmur, com área de cisto ósseo aneurismatico. A escolha do local de biópsia deve permitir a obtenção de amostra representativa da heterogeneidade da lesão. A) COA ; B) TGC
Figure 3: Giant cell tumor of the femur, with an area of ​​aneurysmal bone cyst. The choice of the biopsy site should allow obtaining a representative sample of the heterogeneity of the lesion. A) COA; B) TGC

The choice of the biopsy site must allow obtaining a representative sample of the heterogeneity of the lesion:  A) COA  ;  B) TGC

Figura 4: Ressonância magnética, corte sagital, de tumor de células gigantes do fêmur, com área de cisto ósseo aneurismatico. Observa-se que a lesão apresenta áreas de conteúdo líquido (a-COA) e áreas sólidas (b-TGC).
Figure 4: Magnetic resonance imaging, sagittal section, of a giant cell tumor of the femur, with an area of ​​aneurysmal bone cyst. It is observed that the lesion has areas of liquid content (a-COA) and solid areas (b-TGC).
Figura 5: Corte axial de ressonância magnética de tumor de células gigantes do fêmur, com área de cisto ósseo aneurismatico. Idem: conteúdo líquido (a-COA) e áreas sólidas (b-TGC).
Figure 5: Axial MRI section of a giant cell tumor of the femur, with an area of ​​aneurysmal bone cyst. Idem: liquid content (a-COA) and solid areas (b-TGC).

It is observed that the lesion has areas of liquid content ( a-COA ) and solid areas ( b-TGC ).

The anamnesis and images of the lesion must be carefully analyzed, the biopsy site must be chosen that allows a sample to be taken from the different areas that appear heterogeneous on MRI, to allow for an accurate diagnosis.

The classic aneurysmal bone cyst has a homogeneous appearance, while the aforementioned tumor lesions, when accompanied by areas of aneurysmal bone cyst, necessarily become heterogeneous.

It is more frequent in the first three decades of life, with its peak incidence between 5 and 20 years of age, with a slight predominance in females.

The patient generally presents with mild pain at the site of the injury and when the affected bone is superficial, inflammatory signs such as increased volume and heat can be observed. Generally, the patient correlates the onset of symptoms with some trauma.

In evolution there may be a slow, progressive or rapidly expansive increase. It affects any bone, most frequently the lower limbs (tibia and femur representing 35% of cases) and vertebrae, including the sacrum and in the pelvis mainly the iliopubic branch. They can mimic joint symptoms when located in the epiphysis. Compromise in the spine can cause compressive neurological symptoms, although in most cases it affects the posterior structures.

GOALS

At the end of reading this chapter, the reader will be able to:

  • know the group of pseudo-tumor lesions;
  • characterize the typical aneurysmal bone cyst;
  • determine the imaging tests necessary to clarify the injury;
  • make the differential diagnosis;
  • choose the best treatment for each situation.

CONCEPTUAL SCHEME: COA

Figura 6: No estadiamento ósseo realizado com a cintilografia encontramos lesão única com captação discreta na periferia da lesão.
Figure 6: In the bone staging performed with scintigraphy, we found a single lesion with discrete uptake on the periphery of the lesion.
Figura 7: A tomografia revela área radiolucente; erosão óssea; afilamento da cortical e insuflação. sem focos de calcificação.
Figure 7: Tomography reveals a radiolucent area; bone erosion; cortical thinning and inflation. no foci of calcification.
Figura 8: COA da tíbia com insuflação da cortical.
Figure 8: AOC of the tibia with cortical inflation.
Figura 9: Aspecto homogênio com erosão da cortical.
Figure 9: Homogeneous appearance with cortical erosion.

In the bone staging performed with scintigraphy, we found a single lesion with discrete uptake on the periphery of the lesion.

Radiographically, it appears as a radiolucent insufflation lesion, preferably in the metaphyseal region of long bones (it can also occur in the epiphysis and diaphysis), with the presence of septa scattered throughout its content, with a “bullous” (or honeycomb) appearance, with thinning and expansion of the cortex, eccentric in 50% of cases or central location. They can also occur centrally in the cortical bone and in less than 8% of cases on the surface.

The radiographic appearance, however, is homogeneous. As the lesion progresses, a Codman’s triangle may form, giving a false impression of soft tissue invasion, which does not occur because the lesion always has a surface of connective tissue that circumscribes it (pseudo-capsule that delimits the area of injury to the compromised bone and adjacent tissues).  

Magnetic resonance imaging, by performing cuts in different planes, often shows the presence of liquid levels, highlighting the numerous pockets separated by the connective septa. The diagnosis of an aneurysmal bone cyst on biopsy is accepted with greater ease when the MRI analysis of the entire lesion does not reveal any heterogeneous aspect. The presence of a heterogeneous structure on magnetic resonance imaging, in which the solid area presents contrast impregnation, implies the need to obtain a sample from this area for diagnosis, as this must be a case of association of an aneurysmal bone cyst with one of the aforementioned lesions.

Figura 10: Aspecto bolhoso, com septos conjuntivos
Figure 10: Bullous appearance, with connective septa
Figura 11: Níveis líquidos.
Figure 11: Liquid levels.
Figura 12: Curetagem intralesional, bolsas com conteúdo sanguíneo.
Figure 12: Intralesional curettage, pockets with blood content.
The treatment of choice has been marginal resection or intralesional curettage, followed by filling the cavity with an autologous or homologous graft, when necessary. The cavity can also be filled with methylmethacrylate, although our preference is to use an autologous graft when possible, as it is a benign lesion. Some authors associate intralesional adjuvant treatment with the application of phenol, electrothermia or cryotherapy. In classic aneurysmal bone cysts, I do not see the point of this therapy, which, however, should be applied when the surgeon finds a “suspicious” area that was not detected on imaging. If the aforementioned benign tumors are involved, which may be accompanied by areas of aneurysmal bone cyst, local adjuvant therapy will be beneficial.
Figura 13: Cavidade após curetagem ampla.
Figure 13: Cavity after wide curettage.
Figura 14: Aspecto macroscópico do material obtido da cavidade.
Figure 14: Macroscopic appearance of the material obtained from the cavity.
Figura 15: Preenchimento da cavidade com enxerto ósseo.
Figure 15: Filling the cavity with bone graft.

Some bone segments such as the ends of the fibula, clavicle, rib, distal third of the ulna, proximal radius, etc. can be resected, without the need for reconstruction.

In other situations, we may need segmental reconstructions with free or even vascularized bone grafts or joint reconstructions with prostheses in advanced cases with major joint involvement. In the spine, after resection of the lesion, arthrodesis may be necessary to avoid instability.

Radiotherapy should be avoided due to the risk of malignancy, however it is reserved for the evolutionary control of lesions that are difficult to access, such as the cervical spine, for example, or other situations in which surgical reintervention is not recommended.

Embolization as an isolated therapy is controversial. However, it can be used preoperatively to minimize bleeding during surgery. This practice is most often used in cases of difficult access, although its effectiveness is not always achieved. Infiltration with calcitonin has been reported with satisfactory results in isolated cases.

Recurrence may occur, as the phenomenon that caused the cyst is unknown and we cannot guarantee that surgery repaired it. The recurrence rate can reach thirty percent of cases.

Questions:

1- The aneurysmal bone cyst:

a- it is a tumoral lesion

b- it is a metastatic lesion

c- occurs alone or accompanies other bone injuries

d- it is a pseudo-aneurysm

 

2- Differential diagnoses of COA include:

a- Chondrosarcoma

b- TGC

c- Ewing sarcoma

d- cortical fibrous defect

 

3- According to Enneking’s classification, the COA is:

a- active benign lesion

b- latent benign lesion

c- low-grade malignant lesion

d- high-grade malignant lesion

 

4- In relation to the COA, it is correct to state:

a- occurs more frequently in elderly patients

b- presents osteoclast-type giant cells

c- should preferably be treated with wide resection

d- presents foci of calcification

 

5- The radiographic appearance of the COA is:

a- condensing bone lesion

b- heterogeneous bone lesion

c- homogeneous bone rarefaction lesion

d- bone lesion without precise limits.

 

6- The preferential treatment of the COA is:

a- intralesional curettage

b- segmental resection

c- segmental resection + endoprosthesis

d- Arthrodesis

 

7- The tumor lesions that most frequently present areas of aneurysmal bone cyst are:

a- tgc; chondrosarcoma; osteosarcoma and Ewing’s sarcoma 

b- fibrous defect; tgc; adamantinoma and chordoma

c- osteoblastoma; chondroblastoma; chondromyxoid fibroma and tgc;  

d- osteosarcoma; chondroblastoma; eosinophilic granuloma and lipoma

 

Bibliography

 

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Author: Prof. Dr. Pedro Péricles Ribeiro Baptista

 Orthopedic Oncosurgery at the Dr. Arnaldo Vieira de Carvalho Cancer Institute

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Chondrosarcoma or Chondroma

Chondrosarcoma or Chondroma. For a better understanding of the differential diagnosis of chondroma and grade I chondrosarcoma, let’s discuss the case:

Female patient, 39 years old , odontologist , right handed. The patient refers pain in his right shoulder for about eight months. The first doctor performs radiographs of the cervical spine and indicated physical therapy for cervical spine ( Figure 1). Not getting better, performs magnetic resonance imaging of the ervical spine, which showed no cervical lesions(Figure 2).

CHONDROSARCOMA and CHONDROMA: Differential Diagnosis, Management and Treatment.

Figura 1: Radiografia (RX) da coluna cervical, sem alterações.
Figure 1: Radiography of the cervical spine without lesions.
Figura 2: Ressonância (RM) da coluna cervical sagital (sag) T1, normal.
Figure 2: Magnetic Resonance (MR)) of the sagittal cervical spine (sag) T1, normal.

However, analysis of this examination showed lesions in the proximal humeral metaphysis, characterized by low signal and intermediate signal in T1 and high signal on T2 ( Figures 3 and 4 ).

Figura 3: RM com lesão na metáfise proximal do úmero direito, apresentando sinal intermediário e áreas de baixo sinal em T1, que devem corresponder a focos de calcificação.
Figure 3: MR with lesions in the proximal metaphysis of the right humerus, with intermediate signal and low signal areas in T1, which must correspond to foci of calcification.
Figura 4: RM coronal (cor) T2, lesão heterogênea com áreas de alto sinal entremeadas com áreas de baixo sinal (focos de calcificação).
Figure 4: coronal MR (cor)T2, heterogeneous lesion with areas of high signal intensity interspersed with low signal areas (calcified foci).
After a week , new resonance examination was conducted to evaluate this finding. This humeral resonance imaging showed a solid lesion , heterogeneous, with low signal and intermediate signal on T1, replacing the bone marrow fat (Figure 4a ). In the sagittal T1 spir, we see escaloped erosion of the endostal cortex.(Figure 4.b ). Careful analysis of magnetic resonance images, showed the aggressive characteristics of the lesion: with erosion of endosteal cortex; areas with hyposignal and areas of hyperintensity , heterogeneous pattern, with contrast uptake and calcification foci , which are most evident in the resonance PD ( proton density ) (Figures 5.a – 5.d ).
Figura 4.A: Ressonância coronal T1, evidenciando lesão meta-diafisária, sólida, heterogênea, com baixo sinal e sinal intermediário em T1, substituindo a gordura da medular óssea.
Figure 4.A: Coronal T1 MR , showing meta-diaphyseal injury, solid, heterogeneous, with low signal and intermediate signal on T1, substituting fat from bone marrow .
Figura 4.B: Ressonância em sagital T1 Spir, verifica-se erosão da cortical interna, lesões em saca bocado.
Figure 4.B : MR in sagittal T1 Spir , there is erosion of the endostal cortex, scalloped erosion.
Figura 5.B: RM ax DP: Lesão heterogênea com áreas de alto sinal e baixo sinal.
Figure 5: The: Color MR T1, irregular metaphyseal lesion with low signal areas. Figure 5B: MR ax DP: heterogeneous lesion with areas of high signal and low signal.
Figura 5.D: RM cor spir, com forte captação de contraste.
Figure 5.C: MRT1 Spir, scalloped erosion of the endostal cortex is observed. Figure 5.D: MR cor, spir color, with strong contrast enhancement.

The radiograph of this region, held on 24 July 2003 , two weeks later , highlighted the presence of this metadiafisiary injury, occupying two thirds of the proximal humerus.

This image shows scalloped areas due to the erosion of the endostal cortex, making the secondary enlargement of the bone marrow and areas of condensation dotted with cotton wool spots aspect , suggesting calcified foci (Figure 6.a ).

After this finding , it was referred to oncologist , requesting tests to investigate and stage the lesion . Scintigraphy performed: uptake was observed only in the right humerus (Figure 6.b).

Then a biopsy which revealed  cartilage tissue without atypia , suggesting new biopsy ( Figure 7).

Figura 6.A: Rx do úmero com lesão meta-diafisária, com focos de calcificação, alargamento da medular e erosão da cortical interna.
Figure 6.A: Rx humerus with meta-diaphyseal lesion with calcified foci, bone marrow enlargement and erosion of the endostal cortex
Figura 6.B: Cintilografia evidenciando hiper-captação na região proximal do úmero direito.
Figure 6.B : Scintigraphy showing hyper-uptake in the proximal region of the right humerus.
Figura 7: Relatório da anatomia patológica identificando tecido cartilaginoso, sugerindo nova biópsia.
Figura 7: Relatório da anatomia patológica identificando tecido cartilaginoso, sugerindo nova biópsia.
The shoulder pain and imaging findings of aggressive lesion with calcified foci, indicate the possibility of Chondrosarcoma. In this case the differential diagnoses between Chondroma and more remotely from Bone Infarction should be discarded due to the following considerations: 1- The patient went to the doctor because of progressive pain, was not a casual examination found. 2- The rays show metaphyseal enlargement, endostal cortex erosion and foci of calcification, which associated with the clinical symptoms indicates that it is active lesion, with local aggressiveness and points to the diagnosis of Chondrosarcoma. 3- The MR complement the image data and awaken the reasoning, concluding the same diagnosis. 4- The biopsy revealed that it was a “cartilaginous tissue,” there is no logic to suggest new biopsy in this situation. A second biopsy, in this case, became in an academic discussion because of the histopathological diagnosis of Chondroma and Chondrosarcoma grade I is often difficult, and the conduct of the treatment here is surgical. As we know that surgery is the only treatment that can cure Chondrosarcoma, this case must be approached and treated surgically as a Chondrosarcoma, regardless of whether the eventual biopsy comes with the previous diagnosis of Chondroma. The biopsy may have its indication just to confirm that it is a cartilage injury. The first doctor chose to perform a biopsy, with Jamshidi needle. The result of the pathological examination was cartilaginous lesions without atypia. Concerned about the aggressive image of the lesion did not feel peaceful in treating the case as a chondroma and not of assume a policy of treating as a Chondrosarcoma. Proposed to observe patient for two months. After this period the patient returns, still with the same clinical feature. The doctor indictes new MR, observing the same previous aspects, the biopsy scar and a new findin:the presence of extra-cortical tumor, infected all subcutaneous tissue (Figures 8a 8.b, 8.c and 9 ).
Figura 8.A: Rm cor T1, observa-se o levantamento periosteal e lesão extra cortical.
Figure 8A: Color MR T1, we observe the survey periosteal and cortical extra injury.
Figura 8.C: Rm cor T2, com supressão de gordura evidencia tumor extra cortical, contaminando o espaço sub-periósteo.
Figure 8.B: MR ax T1, path contamination of the biopsy.
Figure 8.C: MR color T2 with fat suppression shows extra cortical tumor, contaminating the sub-periosteal space.
Figura 9: Rm ax T1, com saturação de gordura, evidencia o edema da cicatriz da biópsia e a implantação de tumor nos tecidos moles, no trajeto da biópsia.
Figure 9: Rm ax T1 with fat saturation: evidence of edema in scar biopsy and tumor implantation in soft tissue at the biopsy path.
After this last exam , the doctor offers to perform another biopsy. The patient decides to consult another professional , seeking a second opinion and joint us. The specialist in orthopedic oncology, must complete the diagnosis and define the conduct at this time . Must not launch a new biopsy because what action it will take if this biopsy is not conclusive for Chondrosarcoma ? What to do if the result is Chondroma ? With clinical data that revealed progressive pain, imaging with locally aggressive lesion and even the pathology of cartilage injury, the expert has all the parameters to indicate the treatment of this injury as Chondrosarcoma , for the histopathological diagnosis of Chondroma and Chondrosarcoma Grade I it is very difficult and sometimes controversial (Figures 10 and 11).
Figura 10: lâmina de condroma
Figure 10: Chondroma blade
Figura 11: Lâmina de condrossarcoma grau I. Tecido cartilaginoso, com vacúolos contendo mais de um núcleo. Imagem de erosão do tecido ósseo pelo avanço do tumor
Figure 11: Chondrosarcoma Grade I: cartilaginous tissue, with vacuoles containing more than one core. Arrows show the erosion of the bone tissue due to tumour invasion

The same slide, presented to the same pathologist, after some time, may have changed the report of Chondroma to Chondrosarcoma to Grade I or Grade I Chondrosarcoma to Chondroma. Still, if this same slide is displayed to other pathologists, we can get the two different diagnoses. We know that the final diagnosis of bone tumors must have CLINICAL-RADIOLOGICAL and pathologic correlation. The pathologist usually is only analyzing the blade. Who is leading the case is who has all the data. We must therefore enhance the imaging and all the clinical picture in this situation.

After these considerations, surgical treatment is necessary. Chondrosarcoma is unresponsive to chemotherapy or radiotherapy. It can be cured with surgical resection with oncologic margin, because unfortunately relies on locally when this margin is not achieved. In relapse can occur dedifferentiation, invasion of adjacent tissues that impede the limb salvage surgery, as well as providing the occurrence of metastases.

You can not miss the opportunity to heal this injury with the appropriate surgery.

Careful analysis of the images of this case indicates the need for wide resection with margin and replacement with nonconventional prosthesis.

It is contraindicated intralesional curettage, even with adjuvant site and fill with cement, because the recurrence and dedifferentiation are frequent with this conduct.

After this clarification to the patient, we perform a resection of two proximal humerus thirds, including the skin and the path of the biopsy, because in addition of Chondrosarcoma can deploy soft tissue, this was already happening in this case in the biopsy path.

For the reconstruction of the humerus, we employ a nonconventional endoprosthesis built in polyethylene. These are lighter than metal, have elasticity similar to that of bone and allow drilling holes, where necessary, to reattach the remaining ligaments and muscles. Around the polyethylene is a fibrotic reaction involving the prosthesis and fixed definitely the soft tissues reinserted.

In detail, we present the steps of the surgery, reconstruction with endoprosthesis and pathological anatomy of the piece (figures 12 to 23).

Figura 12: Paciente posicionada em decúbito dorsal horizontal. Assepsia e antissepsia, com exposição de todo o braço.
Figure 12: Patient positioned in the supine position. Area cleaning and disinfection with exposure around the arm.
Figura 13: Incisão antero-lateral do braço direito, abertura de pele, tecido celular sub-cutâneo e hemostasia. Dissecção do segmento afetado, incluindo todo o trajeto da biópsia.
Figure 13: anterolateral aprouch on right arm, opening skin, subcutaneous tissue and hemostasis. Dissection of the affected segment, including all the way biopsy.
Figura 14: Liberado os dois terços da extremidade proximal do úmero. Dissecção e hemostasia. Em detalhe o tendão longo do músculo bíceps, inserido na glenóide.
Figure 14: Released two thirds of the proximal humerus. Dissection and hemostasis. In detail the long tendon of the biceps muscle, inserted into the glenoid.
Figura 15: Mensuração do segmento a ser ressecado.
Figure 15: Measurement segment to be resected.
Figura 16: Segmento ressecado em conferência com a endoprótese confeccionada em polietileno e titânio, desenhada por Roberto Fabroni e produzida pela IMPOL, utilizada na reconstrução.
Figure 16: Segment resected and nonconventional endoprosthese made of polyethylene and titanium stem, designed by Roberto Fabroni and produced by IMPOL used in the reconstruction.
Figura 17: Após a osteotomia, realizamos o alargamento do canal medular, onde será cimentada a prótese.
Figure 17: After osteotomy, performed the enlargement of the spinal canal, where it will be cemented prosthesis.
Figura 18: Após a cimentação da haste, realizamos a reinserção da cápsula articular e dos músculos remanescentes, nos orifícios do polietileno da prótese, para obtermos a melhor funcão.
Figure 18: After cementing the stem, held the reintegration of the joint capsule and the remaining muscles in polyethylene holes of the prosthesis, to obtain the best user function.
Figura 19: Reinserção do músculo deltóide e aproximação do subcutâneo.
Figure 19: Reintegration of the deltoid muscle and subcutaneous approach.
Figura 20: Em destaque o local da biópsia, a pele e todo o trajeto sendo ressecado, a mensuração do segmento a ser ressecado e a peça ressecada em bloco, com margem oncológica.
Figure 20: Highlights the biopsy site, skin and all the way being resected, the segment measurement to be resected and the resected specimen block with oncologic margin.
Figura 21.A: Segmento ressecado, incluindo o tecido celular subcutâneo e pele, do trajeto da biópsia.
Figure 21.A: resected segment, including the subcutaneous tissue and skin, the biopsy path.
Figura 21.B: Radiografia da peça documentando os tecidos moles ressecados.
Figure 21b: X-ray of the resected piece documenting the dry soft tissue.
Figura 22.A: Corte da peça. Observamos o tumor ocupando o segmento proximal do úmero.
Figure 22.A: Cut of the piece. We observe the tumor occupying the proximal segment of the humerus.
Figura 22.B: Em maior aumento, a seta aponta a disseminação do tumor nos tecidos moles.
Figure 22.B: In greater increase, the arrow indicates the spread of the tumor in soft tissue.
Figura 23: Corte da peça ressecada com o trajeto da biópsia contaminado, a seta destaca a lesão extra cortical e a ossificação do periósteo e a lâmina da Histologia destaca a erosão da cortical pelo tumor.
Figure 23: Cut of the resected piece with the path of the contaminated biopsy, the arrow highlights the extra cortical injury and ossification of the periosteum and the blade of Histology highlights the erosion of the cortical tumor.

The oncologic surgery should first seek resection in order to obtain margins decreasing the possibility of local recurrence . Reached this goal , the best reconstruction should be performed to restore function , the closer to normal point. In nonconventional endoprostheses, made ​​to reconstruct tumor resection, we can not be expected the same function as conventional prostheses used in arthritis or in other indications, since in each case there will be a loss of muscles and healthy soft tissues, larger or smaller, resected due to need to obtain oncologic margin.

Physiotherapy driven professional who knows the surgery is critical to achieve a good functional results (Figures 24 to 27).

Figura 24: Pós operatório de dois meses. observa-se boa cicatrização, diminuição do volume do ombro devido à perda de tecidos ressecados como margem e hipotrofia muscular
Figure 24: Post-operative two months. observed good healing, decreased shoulder volume due to loss of tissue resected margin and as muscle hypotrophy.
Figura 25.A: A paciente consegue alcançar o queixo com a mão.
Figure 25.A: The patient can achieve his mouth with his hand.
Figura 25.B: Limitação da rotação interna. A paciente alcança a nádega.
Figure 25.B: Limitation of internal rotation. The patient attains buttock
Figura 26.A: Pós operatório de sete meses, a paciente alcança a orelha.
Figure 26.A: Post operatively seven months, the patient reaches the ear.
Figura 26.B: Melhora da rotação interna, alcançando L2.
Figure 26.B: Improved internal rotation, reaching L2.
Figura 27.A: Após um ano, alcançando a região da orelha.
Figure 27.A: After a year, reaching the region of the ear.
Figura 27.B: Melhora da rotação interna, após um ano consegue chegar a T11.
Figure 27.B: Improved internal rotation after a year can reach T11.
We can observe the funtional outcome three years after surgery ( Video 1 ).
Video 1: Patient after three years of surgery and performing his professional duties.

After ten years and seven months the patient did not present any complaint. Leans casually in his chair on the right elbow operated arm (Figure 28) , can raise his hand to his mouth (Figure 29Aa), good internal rotation (Figure 29b).

Figura 28: Paciente após dez anos de cirurgia, apoiando descontraidamente sobre o braço operado.
Figure 28: Patient after ten years of surgery, resting casually on the operated arm.
Figura 29.A: Elevação da mão até a orelha, dez anos após.
Figure 29.B: Hand lift to the ear, ten years after.
Figura 29.B: Após dez anos da cirurgia, com excelente rotação interna, alcançando a escápula. Sem dificuldade para o exercício profissional de odontóloga
Figure 29.A: After ten years of operation, with excellent internal rotation, reaching the scapula. No problem for the professional practice of odontologist

The patient has good function and works very well , without any difficulty , in their professional activities as Odontologist ( Video 2 ).

Video 2: Patient with ten years after surgery, without complaint and exercising his profession of odontologist all these years.

The patient has good function and plays very well, without any difficulty, their professional activities (Video 2).

The patient has good function and plays very well, without any difficulty, their professional activities (Video 2).

REVIEW:     

Chondrosarcoma is the primary malignant bone tumor more frequent  after osteosarcoma 23,24). The central subtype is the most common and affects more than five times the periferic (3), there are also rare subtypes of clear and mesenchymal cells (2).

Normally arises in the bones of endochondral origin and mainly at the root of the limbs (shoulder, pelvis, rib and spine (1)) are rare in the membranous origin (24,11,15,14). It is slow growing and often the patient seeks treatment when the lesion presents major. This tumor can affect any age, with prevalence between 30 and 40 years (7, 11, 22), with reference in the literature since three years (15) to 73 years old (1).

It is a malignant tumor of mesenchymal nature, producing interstitial substance and cells that assume aspect of hyaline cartilage, with varying degrees of immaturity and frequent calcification foci and can occur in different locations.

Can be classified according to location: A- Central , B- cortical fair (Paraosteal or Periosteal) (23,2,24,6,3), C-Peripheral (or exophytic, which occurs in the cartilaginous cap of an osteochondroma) (28)  and D- Soft Tissue Chondrosarcoma (13); on the histology in: A- degree of anaplasia: are classified into grades I, II and III, dedifferentiated; B-, C- and D-:mesenchymal clear cell; as to the origin may still be: 1 primary and 2 secondary (which originates at the site of a preexisting benign cartilaginous lesion as in Oilier disease (Enchondromatosis) or Maffucci syndrome processing for Chondrosarcoma is common (20 to 30 %) (2.28), can also occur as Solitary Osteochondroma (in less than 1%, or multiple 10%) (2), and more rarely secondary to Paget’s disease.

Pain can be insidious symptoms for several years, progressing to slow growth, volume increase, mobility restriction getting skin sometimes reddish and warm (23). The first symptom is often a fracture in pathological bone (2.24).

The radiograph shows transparent radio metaphyseal lesions replacing the bone marrow that extend into the epiphysis or diaphysis , eroding the internal cortical ( lesions in piecemeal ) , inflating or expanding the medullary portion of the bone , but remaining bounded by cortical that thick.

The appearance of calcifications ( dotted such as cotton balls ( 5 ) or rings ) is frequently (23, 2 , 24, 13 , 6, 28) . These are due to the degeneration of the cartilage that receives new vascularization and calcified . This process is accelerated in Chondrosarcoma and slow in benign cartilage lesions and low grade.

The bone mapping assists in  lesion staging. MR  and CT are important for the evaluation of the intramedullary extension and extra osseous lesion ( 2).

The diagnosis of well-differentiated Chondrosarcoma presents difficulties and histological data from clinical history, location, imaging findings should be valued for diagnostic conclusion and definition of proper behavior (23, 14, 12 ) . The irregularity of histological minutiae in the array and the number of cells within the chondroid matrix, the core of hyperchromasia changes , polymorphism and atypical mitotic when located in members of roots must be considered grade I Chondrosarcomas , although these same histological aspects can be found in benign Chondromas of hand and feet.  In microscopic descriptions are similar to Central Chondrosarcomas ( 23).

For the diagnosis we must also differentiate the pathological , clinical and radiological similarities with other injuries.

The diferential diagnosed with aneurysmal bone cyst is on the multiloculated character; with Chondroma , the Osteochondroma , Chondroblastoma , the Paraosteal and Periosteal Osteosarcoma (with cortical just Chondrosarcoma ) ( 16); Myositis Ossificans ; Fibroma Chondromyxoid ; T.G.C. and Non-Hodgkin Lymphoma ( 23 , 6, 28) . The Clear Cell Chondrosarcoma has intra lesional formation of reactive bone may cause confusion with Osteosarcoma . The Mesenchymal Chondrosarcoma is formed by small round cells that resemble Hemangiopericytoma and Ewing’s sarcoma ( 14). The central Chondroma of long bones, Chondrosarcoma and Bone Infarction are often difficult to diagnose , requiring periodically clinical and radiographic evaluation to monitor the evolution of injury and definition of conduct.

A biopsy can often not definitive for diagnosis ( 23, 28 , 12).

The treatment of Chondrosarcoma is exclusively surgery (25 ) , should be chosen a wide resection , including the path of the biopsy (21, 13). Radiation therapy is ineffective ( 6) in controlling this cancer. For cases of grade III can be argued chemotherapy indication to the protocol used for  large cell high-grade sarcomas . Mesenchymal Chondrosarcoma in which present predominance of small cell undifferentiated , discussed the chemotherapy lies with the treatment protocol of Ewing ‘s sarcoma. In both cases the response to chemotherapy is usually poor ( 6). The treatment of this cancer should be individualized for each clinical subtype.

Complications occur hematogenous metastases to the lungs ( 28) , may also present lymphatic dissemination and local recurrence. Many chondrosarcomas feature local invasion trend (14 ), reaching enormous sizes becoming inoperable and causing death by this local complications propagation.

The local recurrence increases the incidence of lung metastases ( 21).

EXERCISES:

1- What are the radiographic features of Central Chondrosarcoma ?

a) Intra and extra medullary ossification.

b) Diaphyseal lesion with bone thinning and triangle of Codman with coarse lamellar reaction.

c) Areas of bone thinning , internal cortical erosion and calcification foci.

d) Bone condensing areas with periosteal reaction onion skin.

Answer: c) the cartilaginous tissue is more radiopaque than bone and thus presents itself as causing bone thinning and enlargement of medullary lesions in the bone marrow cousing cortical erosion . This growing cartilaginous tissue gets vascular sprouts and cartilage comes into regression due to calcification.

2- What are the characteristics of the MR of Chondrosarcoma ?

a) hyper- signal in T1, T2 and low signal with contrast enhancement.

b) hypo- signal in T1, hypo- signal in T2 and capture the contrast.

c)hypo- signal in T1, hyper- signal in T2 and without contrast uptake.

d)low signal on T1, high signal on T2 and capture the contrast.

Answer: d ) the cartilage tissue has low to intermediate signal on T1 . Intermediate down the cartilage and the calcified foci . Displays contrast uptake by increasing the local metabolism due to cancer.

3- What are the main differential diagnosis of Central Chondrosarcoma ?

a) Bone infarction and chondroma.

b) Osteochondroma and Ewing’s sarcoma

c) Osteomyelitis and T.G.C.

d) Osteosarcoma and condroblastoma.

Answer: a ) Bone  Infarction causes damage to the bone marrow , but does not cause erosion of the inner cortex and has no evolutionary character of pain. It is usually a diagnosis finding on occasional ray.The same applies to the Chondroma that does not evolve and is only cartilaginous remains of development.

4- What is the treatment for the central chondrosarcoma ?

a) Intralesional curettage and autologous bone graft.

b) Wide resection and replacement with nonconventional endoprosthesis.

c)Intralesional curettage , location adjuvant with liquid nitrogen and homologous bone graft.

d)Intralesional curettage , local adjuvant electrotherm and bone cement.

Answer : b ) The wide resection provides oncological treatment and reconstruction with nonconventonal endoprosthesis  provides the best restoration of function.

5- Histologically it is difficult differential diagnosis between:

a)Osteosarcoma and Eosinophilic granuloma.

b)Grade I Chondrosarcoma and Chondroma.

c)T.G.C and Ewing’s sarcoma.

d) Osteoblastomas and Enchondroma.

Answer: b ) The central long bones Chondroma and chondrosarcoma grade I are often difficult to histological diagnosis , it requires the radiographic evaluation for the definition and conduct.

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Autor : Prof. Dr. Pedro Péricles Ribeiro Baptista

 Oncocirurgia Ortopédica do Instituto do Câncer Dr. Arnaldo Vieira de Carvalho

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