FISIOPATOLOGIA OSTEOSARCOMA PDF

Language: English Portuguese. Osteochondromas are bone protuberances surrounded by a cartilage layer. They generally affect the extremities of the long bones in an immature skeleton and deform them. They usually occur singly, but a multiple form of presentation may be found. They have a very characteristic appearance and are easily diagnosed. In these cases, imaging examinations that are more refined are necessary.

Author:Gardaramar Tojashakar
Country:Togo
Language:English (Spanish)
Genre:Science
Published (Last):17 June 2006
Pages:406
PDF File Size:13.62 Mb
ePub File Size:12.90 Mb
ISBN:974-8-11357-387-7
Downloads:55798
Price:Free* [*Free Regsitration Required]
Uploader:JoJotaur



Language: English Portuguese. Osteochondromas are bone protuberances surrounded by a cartilage layer. They generally affect the extremities of the long bones in an immature skeleton and deform them. They usually occur singly, but a multiple form of presentation may be found.

They have a very characteristic appearance and are easily diagnosed. In these cases, imaging examinations that are more refined are necessary. Atingem, habitualmente, as extremidades dos ossos longos no esqueleto imaturo e os deformam.

Debate continues as to whether osteochondroma is a developmental disorder pseudotumoral lesion or a neoplasm. Anteroposterior AP radiograph A and lateral radiograph B of the left knee.

Note exostosis osteochondroma — arrows in the proximal region of the tibia in a skeletally immature patient. According to the World Health Organization WHO , osteochondromas are bone projections enveloped by a cartilage cover that arise on the external surface of the bone.

They present two distinct clinical forms 5 : single lesions solitary osteochondromas and several lesions multiple osteochondromas.

This entity is also known as an osteochondromatous exostosis, 1 osteocartilaginous exostosis 4 , 5 or simply exostosis. Among the various synonyms used in the literature, the commonest ones are: hereditary multiple exostosis, multiple cartilaginous exostosis, hereditary osteochondromatosis and multiple hereditary osteochondromatosis. Osteochondromas more frequently affect the appendicular skeleton upper and lower limbs.

After osteochondromas appear in the long bones, they usually become located in the metaphysis and only rarely in the diaphysis. The long bones of the lower limbs knee region are most commonly affected. A Simple lateral radiograph. B Computed tomography with 3D reconstruction. Note lesion arrows in the proximal region of the tibia. Image of 3D reconstruction from computed tomography of chest.

Note single exostosis inside black oval figure in the region of the body of the left scapula, beside the ribs. Despite the slight predominance of the male gender over the female gender that has been reported by some authors, 4 , 5 , 7 it seems that there is no effective predilection according to sex.

Some authors have reported that the incidence of multiple osteochondromas is , individuals. Hereditary multiple exostosis. A and B In the knees, radiographs showing multiple lesions in the proximal regions of the tibias and fibulas.

The ages of patients with multiple lesions are similar to those of others with single exostoses, and there is also no predilection according to sex. The cause of osteochondromas remains unknown. Based on the similarity of the cartilaginous cover of the exostosis to the growth cartilage growth plate of the bone, several hypotheses have been put forward, all of them relating to alterations to the growth plate.

The variant with multiple lesions is a dominant autosomal alteration 15 , 16 that is transmitted by both sexes and is characterized by the presence of several osteochondromas.

Among solitary osteochondromas, the vast majority are asymptomatic. After they have been detected, they present slowly increasing bulging and hardened consistency, but are painless Fig. In the clinical examination A , painless slowly growing bulging of hardened consistency is sometimes observed. B Radiograph of the proximal region of the right humerus of the same patient.

Symptomatic cases are often related to the size and location of the exostosis. In the immature skeleton, the osteochondroma grows slowly and progressively along with the bone involved, and it stops when skeletal maturity is reached.

In a few cases, pain of greater intensity may be present, associated with complications of a mechanical origin 1 that are promoted by the projection of hard tissue bone into the soft tissues.

In osteochondromas of pedunculate type see imaging diagnostics section , acute pain may occur due to fracturing of the base of the pedicle following local trauma. In the multiple form of this condition, low height, deformities of the bones affected and disproportion between the trunk and limbs can be observed. Radiograph of an individual with hereditary multiple exostosis.

Note the deformity of the forearm due to shortening of the ulna. Rapidly increasing lesion size and local pain processes suggest that sarcomatous transformation is occurring in individuals with osteochondroma that was previously asymptomatic.

Other clinical findings that are occasionally reported include slight increases in soft tissues, elevation of temperature and local erythema. The radiographic appearance reflects the composite nature of the lesion, formed by cortical and medullary bone tissue, 2 which projects outwards from the affected bone.

It is precisely the continuity of the lesion with the surface of the host bone that is pathognomonic for osteochondroma. However, in planar bones pelvis and scapula and irregular bones vertebrae , this relationship and consequently the diagnosis may not be evident on simple radiographs alone Fig. Radiographs showing projecting osteochondromas open arrows in different types of bone. A In the long bones for example, the phalanx — filled arrow , the standard radiographic views two images in orthogonal planes are sufficient for the diagnosis.

B However, in planar bones for example, the scapula — filled arrow and irregular bones, exostoses may not be so evident on simple radiographs alone. The characteristic image consists of an external bone protuberance 1 , 4 and it may have a wide base sessile or a narrow base pedicled or pedunculated Fig.

Because of the singular appearance of these lesions, it is possible in most cases, for example, to do away with biopsies for diagnosing them. Different types of osteochondroma. Note that in examination A , the lesion on the humerus is sessile with wide base — arrows , while in B , it is pedicled or pedunculated narrow base [arrow], i.

The cartilaginous cover is often not visible in these examinations, because its density is similar to that of the surrounding soft tissues. This technique complements radiographs and shows details of the continuity of the cortical and spongy bone inside the lesion 32 , 33 , 34 , 35 , 36 , 37 and their relationship with the adjacent soft tissues Fig. Axial tomographic slices facilitate interpretation 2 of the lesions located in anatomical sites of greater complexity, 23 such as the spine and the belts of the upper and lower limb Fig.

Axial computed tomography slices from the distal region of the thigh. Detail from exostosis in the medial region white oval figure. Note continuity of the lesion with the cortical bone open black arrow and its relationship with the adjacent soft tissues.

Computed tomography images facilitate locating the exostoses white oval figures at anatomical sites of greater complexity such as the spine—sacral region. A Axial image. B 3D reconstruction. This is an examination that also demonstrates the cortical and medullary continuity between the osteochondroma and host bone.

Magnetic resonance images. A T1-weighted sagittal image note hyposignal of the cortical bone and the lesion [open arrows] and hypersignal of the bone medulla in both [filled arrows].

B T2-weighted sagittal image note that the greatest thickness of the cartilaginous cover was around 1. This is accepted as the safest imaging method for evaluating structures adjacent to the osteochondroma and for observing and measuring the cartilage cover 2 , 30 that envelops the exostosis.

The thickness of this layer is used as a criterion for differentiating suspected sarcomatous malignant transformation from cartilaginous tissue 1 , 30 Fig. However, there is no consensus of opinions in this regard. Calcified areas of the cover present low signal intensity in T1 and T2-weighted sequences. The cartilaginous tissue cover of the exostosis may or may not present high uptake of radiopharmaceuticals, both under conditions of normality and in situations of malignant transformation secondary chondrosarcoma.

For this reason, bone scintigraphy does not have great value in differentiating between benign and malignant cartilaginous lesions. The lesion surface is lobulated and has an abundant cartilaginous cover Fig. Intraoperative photograph of excision of an osteochondroma.

Note its multilobulated surface and cartilage cover. Solitary and multiple osteochondromas are histologically similar. Differentiation from normal cartilage is generally done in relation to secondary chondrosarcoma of low-grade malignity. Presence of an exostosis is, in itself, insufficient reason for its surgical excision, especially in isolated cases.

Surgical removal is indicated if the tumor causes pain or functional incapacity, 4 either due to neurovascular compression or due to limitation of joint movement Fig. Another situation for surgical removal relates to fracturing of the base of the osteochondroma. Surgical resection specimen was chosen for this exostosis that was causing vascular compression in the popliteal region. In these patients, the treatment is more complex.

In the multiple forms of this pathological condition, osteochondromas are removed surgically for cosmetic reasons, 43 in order to avoid progression of the bone deformities. In the forearm, for example, simple excision of the lesion in the distal portion of the ulna may impede local deformity.

Sarcomatous transformation is generally treated by means of wide surgical resection, with preservation of the limb, 30 while following rigorous oncological criteria. Among the possible complications of these lesions are fractures generally of pedunculated exostoses, at their base , vascular lesions formation of pseudoaneurysm and neurological complications compression of peripheral nerves, which involves the spine or the periarticular regions , formation of a bursa which affects the cartilaginous surface of the lesion, resulting from local friction and malignant transformation.

Osteochondromas are benign lesions that do not affect life expectancy. However, the risk of malignant transformation to secondary chondrosarcoma should be taken onto consideration, especially in cases of multiple exostoses.

In symptomatic cases or those with atypical locations, other types of imaging examination should be requested, with a view to making a precise diagnosis. In situations in which excision of the osteochondroma is chosen, this is usually curative. Recurrence is seen in cases of incomplete removal. The overall survival of patients with sarcomatous transformation is generally good. However, those with poorly differentiated lesions have a much worse prognosis.

Osteocondroma: ignorar ou investigar?. Rev Bras Ortop. National Center for Biotechnology Information , U. Journal List Rev Bras Ortop v. Published online Oct Author information Article notes Copyright and License information Disclaimer.

KAKURO CHEAT SHEET PDF

Isolation perfusion of the lower limb with platinum

Algunos ejemplos muy bien documentados incluye el tumor en la cara de los monstruos de Tazmania, 3 , fibropapilomatosis en tortugas marinas 4 y carcinoma genital en leones marinos 5. Los gatos son susceptibles a una variedad de factores. El virus se contagia de un gato a otro por medio de la saliva, secreciones nasales, heces y leche. Actualmente, estudios demuestran que el VLFel no puede ser transmitido de gatos a humanos. El VLFel induce linfomas en algunos tumores en gatos.

CHILD DEVELOPMENT AN ILLUSTRATED GUIDE BY CAROLYN MEGGITT PDF

Dahlin's Bone Tumors

We'd like to understand how you use our websites in order to improve them. Register your interest. From August, to February, , a total of 14 patients affected by osteogenic sarcoma of the limbs have been treated at the National Cancer Institute, Milan, Italy. This schedule of treatment is reasonably well tolerated by the patients, despite the side effects and the length of the entire presurgical period.

EICHER BEDIENUNGSANLEITUNG PDF

Osteocondroma: ignorar ou investigar?

Slideshare uses cookies to improve functionality and performance, and to provide you with relevant advertising. If you continue browsing the site, you agree to the use of cookies on this website. See our User Agreement and Privacy Policy. See our Privacy Policy and User Agreement for details. Published on Jun 16, SlideShare Explore Search You.

BUXWV 139 PDF

.

Related Articles