Orbital rhabdomyosarcoma

Introduction to orbital rhabdomyosarcoma Orbital rhabdomyosarcoma is a highly malignant tumor composed of rhabdomyoblasts with different degrees of differentiation. It can occur from birth to adult, and is more common in children under 10 years old. It is the most common intracranial malignant tumor in childhood. Rapid progress, if not treated in time, more than one year of death. Rapidly developing eyeballs and ankle masses are the most prominent features of the disease. basic knowledge The proportion of illness: 0.004% Susceptible people: no special people Mode of infection: non-infectious Complications: cellulitis eyelid abscess

Causes of orbital rhabdomyosarcoma

Cause of the disease ( 30% ):

It is not clear that some cases of orbital rhabdomyosarcoma have a history of trauma, but the exact relationship with the onset is still unclear.

Pathogenesis (30%):

Modern molecular biology research suggests that changes in the expression of genes and functions that control cell growth and differentiation are related to the occurrence of malignant tumors. Studies on point mutations and abnormal expression of oncogenes in orbital rhabdomyosarcoma have found tumor cells in case specimens. The second base mutation of the 12 codon of the N-ras oncogene occurred, and the third base mutation of the 6l codon.

Genetic changes (30%):

The results suggest that N-ras oncogene mutation leads to abnormal expression of gene products, which promotes normal cells to malignant transformation. Under normal circumstances, p53 tumor suppressor gene forms a stable regulatory mechanism together with oncogenes during normal cell metabolism and proliferation. When the p53 gene is abnormally mutated, it will lead to the destruction of this balance and become an important factor in tumorigenesis. The genetic research on orbital rhabdomyosarcoma has just begun, but preliminary results have shown that the oncogene ras and the tumor suppressor gene p53 are in tumor formation. Play an important role.

Orbital rhabdomyosarcoma prevention

1, go to bed early and get up early, exercise the body. Insufficient sleep can reduce the body's immune function, and it is also easy to stimulate the fire, causing external injuries.

2. Keep your mind calm. Avoid anger in the spring, do not be too impatient, always keep your peace of mind.

3. Quit smoking, drink less and drink coffee. Smoking is the most vulnerable to damage to the respiratory surface barrier and induces disease onset. Tobacco, alcohol and coffee all stimulate nervous excitement. Some people want to "eliminate tension and fatigue", but actually weaken the body's disease resistance.

Orbital rhabdomyosarcoma complications Complications, cellulitis, orbital abscess

Acne cellulitis and eyelid abscess may occur when accompanied by infection.

Symptoms of orbital rhabdomyosarcoma Common symptoms Two eyes can not be seen in the pattern of sputum, sputum, sputum, sputum, eyelid closure, incomplete conjunctival congestion, vascular hyperplasia, eyeball protrusion

The age of onset is more than 10 years old. The clinical features are rapid development of the ocular protrusion and ankle lumps. At the same time, it has the appearance of orbital space-occupying lesions and inflammation. The tumor can occur in any part of the iliac crest, but the upper part of the iliac crest is prominent. With the downward shift of the eyeball, the upper anterior humerus and even the eyeball are covered. The tumor is located in the muscle cone and the axial eyeball is prominent. The tumor develops very fast, and the eyeball has a significant increase within a few days. Many patients come to the eyeball for diagnosis. Has been prominent in the eyelids, the occurrence of eyelid regurgitation, conjunctival edema congestion, necrosis and scarring, severe corneal exposure, dry and turbid, internal tumor bleeding can cause sudden increase in eyeball protrusion, due to rapid tumor growth, affecting the front of the sputum The iliac crest often touches the mass, moderate hardness, mild tenderness, and can not be promoted; some tumors have diffuse invasive development, which is characterized by local subcutaneous hardening, lack of obvious boundary, increased skin temperature, accompanied by edema congestion and eyeball protrusion. Like cellulitis, the tumor can also be found through the conjunctiva, with a pink bulge, superficial vascular hyperplasia, dilatation, swelling It can also be polypoid. It protrudes from the upper iliac crest in the cleft palate. If there is bleeding in the tumor, the eyelids see purple and black ecchymoses. As seen in metastatic neuroblastoma, the tumor invades the conjunctiva and can be broken, bleeding and infection. .

Examination of orbital rhabdomyosarcoma

1. Immunological examination Immunohistochemistry was used to detect the expression of ras2l and p53, and the underlying causes of tumorigenesis were identified.

2. Histopathological examination The diagnosis of rhabdomyosarcoma is found in the cytoplasm of the tumor cells. This horizontal pattern is sometimes difficult to confirm in hematoxylin-eosin (HE) staining, using Masson's trichrome staining or phosphotungstic acid-su Wood sperm (PTAH) staining is easy to find. The morphological and cytological features of rhabdomyosarcoma are very extensive. The correct diagnosis should not depend entirely on the presence or absence of transverse stripes. In some cases, the transverse mirror can not be found in the light microscope, and electron microscopy may find In childhood, the development of faster tumors in the orbit, the tumor cells of the spindle-shaped sarcoma should consider the possibility of rhabdomyosarcoma until the final confirmation of other types of tumors.

Rhabdomyosarcoma is generally blocky, irregular in shape, adheres to the eyeball and the internal structure of the eyelid, pale pink, no capsule, soft texture, tender as fish-like, may have a pseudo-envelope and peripheral adipose tissue boundary, microscopic tumor The cell types vary widely and grow in different forms. The shape of the cells varies from small undifferentiated round cells to more differentiated bands, racquets, spiders and giant cells. Horizontal lines are visible in well-differentiated tumor cells, according to the main cells. The components can be divided into different types of rhabdomyosarcoma, which are more simply divided into 3 types: embryonic, acinar and polymorphic.

(1) Embryonic type: The tumor consists of rhabdomyoblasts at different stages of embryonic development. Almost 3/4 of the rhabdomyosarcoma in the orbit is of this type. Microscopically, circular and fusiform cells are seen in the form of a uniform distribution or arrangement for looseness. And closely related cell bands, poorly differentiated tumor cells in a round or small fusiform shape, large nuclear, deep staining, multichromatin in the nucleus, unclear nucleoli, only a small amount of eosinophilic cytoplasm, more nuclear division The small spindle-shaped cell is centrally located, deeply stained, and has cytoplasm on both sides. The above two types of cells are mixed with well-differentiated tumor cells, which are band-shaped, tennis racket or scorpion-like, cytoplasm rich, eosinophilic Dyeing, granular, longitudinal and horizontal stripes, most tumors are rich in blood vessels, and the tumor cells are arranged around the blood vessels.

(2) acinar type: less common than embryonic type, but more shape, due to its structure, such as lung vesicles, named under the microscope, adenoid-like tumor cells and fiber spacing, tumor cells are concentrated, Segmented into a vesicular shape by fibrovascular septum, tumor cells resembling embryonic rhabdomyosarcoma are located in the interval, and there may be several layers of elliptical cells at the edge of the bubble, similar to the glandular epithelium, the central tumor cells are dispersed free, similar to the glandular cavity, the cell size of the central part Unequal, round, may have multiple nuclei, sometimes fibrous spacing protrusions, forming pseudo-nipples, acinar-like arrangement and pseudo-nipple-based histological features, and a few cells contain horizontal stripes, which help to diagnose.

(3) Polymorphism: generally seen in adults, the rarest, composed of tumor cells of different stages of differentiation, its histological features are highly pleomorphic and heteromorphic, mainly spindle cells, in addition to ribbon cells , sickle cells, these cells differentiate well, the volume is larger than the embryo type, the shape is regular, the cells are rich in cytoplasm, and the cytoplasm has vertical and horizontal stripes.

The above classification and tissue image have no relationship with prognosis, and opinions are still inconsistent. Lawrence said that the tissue image has nothing to do with prognosis, and recurrence and death have no obvious relationship with tissue typing.

3. X-ray examination Most of the images showed enlarged and increased density of the sacral cavity. This is because the rhabdomyosarcoma develops rapidly. The tumor volume is larger when the diagnosis is made. The tumor replaces the fat tissue and occupies most of the eyelids. The X-ray film shows the density increase. Soft tissue shadow, and because the child is in the development of eyelids, the increased pressure of the shorter time can cause the enlargement of the sacral cavity, and bone destruction can be found in the late stage.

4. Ultrasonic exploration B-mode ultrasound shows that the lesion is a low-echoic region or an anechoic region with irregular shape. Only a small internal echo is obtained when the gain is increased; if the anechoic region indicates the bleeding cavity, the gain is not increased, and some cases are affected. There is a band-shaped echo interval, the tumor sound attenuation is not significant, the posterior boundary is clear, and the eyeball is pressed by the probe. The lesion image changes are not significant, which is expressed as a solid lesion, that is, no obvious compressibility, and the lesion oppresses the eyeball to make the eyeball The curvature of the wall is flattened or even bulged into the vitreous cavity. This compression of the eyeball is related to the rapid growth of the tumor. Although the benign tumor of the eyelid can also affect the shape of the eyeball, the lesion grows slowly, the extraocular muscle relaxes, and the eyeball has an adjustment. In addition to the special location of the lacrimal gland tumor, the eyeball is more stressed and the ball wall is deformed. The slow growth of the tumor in other parts is less sensitive to the eye wall and makes the eyeball prominent. When the sacral ridge and mass are observed, It can also be probed directly to the surface of the skin for exploration. It not only shows the acoustic properties of the tumor, but also the depth of the tumor. It is meaningful for the choice of surgical approach and intraoperative operation. Color Doppler exploration can find rich and messy color blood flow in the tumor. Pulse Doppler can detect the visible arterial spectrum in the tumor and the blood flow velocity is faster.

5. CT scan CT scan can not make histological diagnosis of rhabdomyosarcoma, but according to the shape of the lesion, boundary, density, bone destruction and other image coups, can make an estimate of the nature of the tumor, in addition, can clearly show the tumor Location and range of involvement are important for diagnosing and developing treatment options.

In most cases, the tumor is located in the upper part of the iliac crest, and the shape is irregular. Only a few cases have lesions occupying the whole iliac crest or located in the posterior part of the iliac crest, but are tapered or round, the tumor boundary is not sharp or the boundary is not smooth, and the tumor has necrotic cavity or hemorrhage. The density is not uniform, the CT value is +34+60HU, and the contrast is obviously enhanced after intravenous injection of contrast contrast agent. The tumor spreads to the surface of the eyeball and grows along the sclera. The sclera is close to the tumor density, and the boundary between the two is unclear. Contact and lack of boundary are often described as cast type; in addition to malignant tumors, inflammatory pseudotumor, hemorrhagic and other invasive lesions can be observed cast pattern, tumor contact with the iliac wall visible bone destruction, about 1 at the time of treatment /3 cases found obvious bone destruction, this bone destruction occurred in the inner wall of the iliac crest, ethmoid cardboard, etc., if the lesion is located at the tip of the sac, the upper wall bone is destroyed or the supracondylar fissure is enlarged, and the lesion can be sinus and cranial fossa Spread, the tumor destroys the dome and spreads to the anterior cranial fossa. The lesion is located in the lower part of the iliac crest to destroy the inferior temporal sinus. It can invade the maxillary sinus or spread to the pterygopalatine fossa through the enlarged subgingival fissure. We can still be observed muscle enlargement.

6. Magnetic resonance imaging shows the position of the tumor, the shape of the magnetic resonance imaging is the same as CT, in which T1WI shows a medium or medium low signal, T2WI intensity increases, is a high signal, the signal is necrotic cavity and bleeding cavity in the tumor Inconsistent with the parenchymal region, both T1WI and T2WI showed a high signal in the hemorrhagic lesion area. In terms of the relationship between the tumor and the eye ring, both of them were moderately low signals on T1WI, so the cast-like change was more significant than CT.

Diagnosis and diagnosis of orbital rhabdomyosarcoma

diagnosis

For children, eyeball protrusion or ankle mass develop rapidly, especially those with eyelid space-occupying lesions and inflammatory manifestations, all of which have diagnostic value. Imaging examination is helpful for diagnosis, and CT shows lesions and bone destruction. There is great value in the spread of the outside world. Children with ocular protrusions, internal hemorrhoids and masses, and the rapid development of the disease should consider the possibility of rhabdomyosarcoma.

Differential diagnosis

In addition, it should be differentiated from sputum cellulitis, xanthomatosis, green tumor, metastatic neuroblastoma, dermoid cyst, optic glioma and intraorbital capillary hemangioma.

1. Imaging examination lacks the imaging features of soft tissue occupying lesions.

2. The occurrence and development of xanthomatosis is slow, with prominent eyeballs, diabetes insipidus, and X-ray and CT examination of the skull with map-like bone loss.

3. Green tumor is an eyelid invasion of acute leukemia, multiple eyes have been diagnosed, immature white blood cells can be seen in peripheral blood, and bone marrow images can be found in various stages of immature cells.

4. Metastatic neuroblastoma Orbital lesions develop rapidly, subcutaneous hemorrhage, adrenal medulla can be found in primary lesions, X-ray and CT can be seen in a wide range of bone destruction.

5. The occurrence and development of the dermoid cyst is slow, and the sacral margin and the pearl-like mass can be seen. The upper wall of the iliac crest is changed, the ultrasound Doppler is used to detect the achromatic blood flow in the lesion, and the CT shows the height inhomogeneity of the tumor. There is a negative CT value area, and the ring is enhanced after the injection of the positive contrast agent, and the humerus is depressed.

6. Optic glioma occurs, development is slow, lack of congestion and edema, early vision loss, optic disc edema or primary atrophy, B-mode ultrasound and CT found optic nerve spindle shape enlargement, optic canal enlargement, MRI can be seen optic nerve enlargement, Spread into the optic canal and the optic chiasm.

7. Intraorbital capillary hemangioma occurs suddenly, and develops rapidly within 3 months, subcutaneous and/or sub-conjunctival purple-red mass, swelling increases when crying, CT scan can find deep lesions, mostly diffuse small pieces High-density shadow, in view of the difficulty in the identification of intraorbital lesions, puncture biopsy is necessary, mainly for mature vascular endothelial cells and capillaries.

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