Rhabdomyosarcoma

Introduction to rhabdomyosarcoma Rhabdomyosarcoma (rhabdomyosarcoma) is a malignant tumor that occurs from embryonic mesenchymal tissue, which is inferior to malignant fibrous histiocytoma and liposarcoma, and ranks third in soft tissue sarcoma. Rhabdomyosarcoma accounts for 15% of children's solid tumors, 50% of soft tissue sarcomas, the diversity of clinical manifestations, the multiplicity of pathological changes and the location of the disease, making rhabdomyosarcoma the most complicated type of pediatric tumors, children and young people See embryonic type, acinar type, more common polymorphic cell type in middle age. More men than women. The head, neck and limbs are more common, and genitourinary tract is also common. basic knowledge The proportion of sickness: 0.00025% Susceptible people: no specific population Mode of infection: non-infectious Complications: liposarcoma

The cause of rhabdomyosarcoma

This disease is a soft tissue malignant tumor composed of various levels of different levels of rhabdomyoblasts. The cause of the tumor is unknown, but genetic factors are not excluded.

Genetic factors (85%)

Molecular biology studies have shown that embryonic rhabdomyosarcoma has an abnormality of chromosome 11p15.5. Gene map analysis showed that there is insulin-like growth factor gene (IGF-2) in this part. Further studies showed that IGF-2 mRNA was highly expressed in both embryonic and acinar-like RMS, and it was present in tumor cells, and there was 11p15.5 region. Gene loss, H19 is an anti-cancer gene at 11p15.5. Embryonic RMS is similar to embryonic skeletal muscle.

Unlike embryonic samples, acinar-like is a highly malignant small round cell tumor that often metastasizes and is confused with Ewing, ssarcoma, primary neuroectodermal tumor, and lymphoma. More than 80% of acinar rhabdomyosarcoma have mutual translocations of chromosomes 2 and 13. The PAX3 gene on chromosome 2 is rearranged with the FKHR gene on chromosome 13, and the PAX3 gene is considered to be an important transcriptional regulator of early neuromuscular differentiation, and the product of the FKHR gene is a transforming factor. The fusion gene of the PAX3 gene and the FKHR gene is considered to be the cause of acinar-like rhabdomyosarcoma.

Rhabdomyosarcoma prevention

When rhabdomyosarcoma is limited to a specific site, it can be treated with chemotherapy for 2 years, and anticancer agents are treated with vincristine, actinomycin D, and cyclophosphamide. When the lesion is further enlarged, resection is impossible, and when it is widely transferred to organs such as lymph nodes and lungs, radiation irradiation is added in addition to the usual chemotherapy. Also a powerful treatment for autologous bone marrow transplantation. Rhabdomyosarcoma, which occurs in the orbit and vagina, is prone to early detection and is difficult to metastasize, so the prognosis is better. However, rhabdomyosarcoma occurring in other areas is likely to recur even if it is temporarily reduced, and it cannot be said that the prognosis is good. After the end of treatment, you must also be regularly checked to try to prevent recurrence.

Rhabdomyosarcoma complications Complications liposarcoma

Tumors occur in the upper part of the iliac crest, especially in the upper quadrant of the eyelid. It can also occur in the posterior or posterior part of the iliac crest. About half of the iliac crest is located in the upper part of the iliac crest. The upper iliac crest has an acute onset, and the iliac crest mass can increase rapidly in a short period of time. Large, and soon developed into unilateral exophthalmos, conjunctival edema, ptosis, skin congestion, swelling, with fever, can be misdiagnosed as sputum cellulitis. If the tumor invades the optic nerve and extraocular muscles, vision loss, eye movement disorder. If left untreated, the tumor can spread throughout the eyelids, involving the sinuses, and even into the brain. Immediate imaging examinations such as CT, MRI, and B-ultrasound can identify the location and extent of the tumor. CT examination can help to confirm the diagnosis if the child shows humeral destruction. If the clinical diagnosis is not clear, it can be used for biopsy pathological diagnosis. In addition, physical examination of the ear and neck lymph nodes for local metastasis.

Symptoms of rhabdomyosarcoma Common symptoms Acute pain olfactory disorder Sensory dysfunction Lymph node swelling Muscle tearing Eyeball vaginal bloody secretions Folding knife phenomenon Muscle contracture nasal congestion

Embryonic rhabdomyosarcoma

Most occur in children under the age of 10, occur in the head and neck, eyelids, genitourinary system, occur in infants, the course of disease is shorter, more than half a year of treatment, due to the rapid development of the disease, the natural course of disease from the appearance of symptoms to death average 16 Months, the main symptoms are painful masses or painless masses, pain often difficult to identify with acute, chronic inflammation, skin surface can form tumor invasive redness, venous light filling or anger, local temperature is high, tumor growth When it is fast, it may be accompanied by skin ulceration and hemorrhage. The size of the tumor varies. It is related to the site of occurrence. Head and neck tumors may have early symptoms, but it is difficult to diagnose. The main symptoms are vague, such as nasal congestion, nosebleeds, headache, and smell. Inappropriate, poor breathing, easy to be misdiagnosed as rhinitis, nasal polyps, tumors in the eyelids can show vision changes, eyeballs prominent, rhabdomyosarcoma of the throat can be mainly hoarseness, progressive progressive, and even cough,, more common in adults, even showing respiratory disorders, genitourinary tumors showing vaginal bloody secretions, hematuria, urethral sarcoma, urinary tract infections, tumors Can be anal lumps, but also because the anus is surrounded by tumor stenosis, can not be anal finger examination, when the tumor is found, may have infiltrated into the pelvic organs, transferred to the pelvic and retroperitoneal lymph nodes, in addition to regional lymphadenopathy, late There are many cases of blood transfer.

2. Acinar rhabdomyosarcoma

High degree of malignancy, mainly occurs in young adults, occurs in the lower limbs, followed by the head and neck, trunk and other places. The Shanghai Medical University Cancer Hospital has reported 104 cases, the disease progresses rapidly, often located in deep soft tissue; more common in limbs and trunks, but also Occurred in the eyelids, in addition to the occurrence of a mass, the tumor can invade the surrounding tissues and organs to produce pain and compression symptoms. When the nerve is violated, it can cause severe pain, inconvenient walking and sensory disturbance. If the tumor grows too fast and is not treated in time, skin edema can be seen. In some cases, lymph node metastasis occurs in the early stage, and the blood is transferred to the lungs. The texture of the mass is like rubber hardness. In addition to blood transfer, lymph node metastasis is often accompanied, and the tumor boundary is unclear. Most cases die within 1 year.

3. Polymorphic rhabdomyosarcoma

Most occur in middle-aged and elderly people, easy to grow in more parts of the human muscle, so the lower limbs and trunk are more common, especially in the deep muscles of the thighs, the size of the tumor is different, the larger diameter can reach more than 20cm, polymorphic Rhabdomyosarcoma is often metastatic, and the tumor often infiltrates into the pseudo-envelope. Multiple nodules are formed in the distant part of the muscle. The length of the disease varies, and it can be diagnosed and treated within one year. However, the tumor growth of some elderly people is slow. The disease course can be more than 20 years, the mass is painful or painless, the tumor is located in the muscle, the boundary is unclear, the boundary is clear when the muscle is relaxed, and the muscle and the tumor are closely related to the muscle when the muscle contracts. This type is characterized by tumor often Large, mostly in 5 ~ 10cm, also up to 40cm, the mass of the mass is hard, cystic or soft when there is bleeding and necrosis, often invading the surface skin, and present local high temperature, adhesion, ulceration and bleeding, and Other deep tumors are different. Polymorphic rhabdomyosarcoma can also have lymph node metastasis. The metastasis rate is second only to synovial sarcoma. Sometimes lymph node metastasis has occurred at the time of initial diagnosis. After a slow period, one third of the cases survive for about five years.

Examination of rhabdomyosarcoma

Do blood routine, liver, kidney function, urine analysis, bone marrow puncture and other laboratory tests, head and neck lesions to do cerebrospinal fluid test, children with rhabdomyosarcoma have no specific plasma or urine markers.

Immunohistochemistry can use antibodies against skeletal muscle and myogenic protein to display striated muscle components in the tumor, antidesmin, multispecific actin, and myoglobin D (MyoD) are the most sensitive markers. , vimentin, myoglobin, dystrophin, cytokeratin, creatine kinase M and B, S100 and neuron specific enolase are used for further differential diagnosis, myoglobin D expression in myogenic The conversion of precursors into muscle cells is important, and in rhabdomyosarcoma this process is inhibited.

Through reverse transcriptase polymerase chain reaction (PCR) and fluorescence in situ hybridization, the diagnosis of rhabdomyosarcoma can reach molecular genetic level and is of guiding significance for the treatment. 2,13q35-q14 gene is found in acinar rhabdomyosarcoma. The site was interrupted, and a tumor growth inhibitory gene was found on chromosome 11 in embryonic rhabdomyosarcoma.

Deoxyribonucleic acid (DNA) content (or ploidy) also has a certain diagnostic value. Shapiro studies have shown that the embryonic type is high-ploid, the acinar type is mainly tetraploid, 37 unresectable rhabdomyosarcoma, 8 All of the diploid children died, while 10 of the 12 high-ploid tumors survived (P < 0.0001), but the results lacked further proof.

Because of the above-mentioned biological, immunological, and cytological diagnostic methods that play an important role in prognostic judgment and treatment, surgeons must obtain enough tumors to ensure that the diagnosis is correct.

1. X-ray examination according to different lesions X-ray film to understand the presence or absence of bone destruction, head and neck should take the skull base film, the upper frontal sinus film, orbital tomography can show the tumor size and bone destruction, vein Renal pyelography can be found in irregular filling defects, as well as hydronephrosis and ureteral dilatation caused by tumor compression. X-ray films of limbs and trunk can be used to understand whether there is calcification in the tumor, whether the bone is damaged or not, and the chest X-ray film should be regarded as Routine examination of various types of rhabdomyosarcoma.

2. Ultrasound detection shows the location, size and extent of the tumor. CT can accurately locate the tumor in each part, especially for abdominal, pelvic, intracranial and cranial tumors.

3. CT showed no characteristic. Rhabdomyosarcoma showed nodular soft tissue mass or uneven mass density shadow. Most of the lesion density was lower than muscle. In some cases, the tumor lesion had higher density and uneven thickness. Ring density shadow.

4. MRI showed a moderately high signal of T1 weighted image and T2 weighted image. The signal level was uneven. Morphologically, the lesion could be clear or unclear, but it was difficult to distinguish it from other soft tissue tumors.

Biopsy needle biopsy or biopsy biopsy can help diagnose.

Diagnosis and diagnosis of rhabdomyosarcoma

According to the medical history, clinical manifestations, dry photo, radionuclide scanning and angiography should be thought of this disease, and the final diagnosis is confirmed by pathology.

Embryonic rhabdomyosarcoma should be differentiated from lymphosarcoma, Ewing's sarcoma, polymorphic rhabdomyosarcoma should be differentiated from malignant fibrous histiocytoma, pleomorphic liposarcoma, and rhabdomyosarcoma should be associated with some poorly differentiated round or spindle cells Identification of sarcoma, including neuroblastoma, neuroepithelial neoplasia, Ewing's sarcoma, poorly differentiated angiosarcoma, synovial sarcoma, malignant melanoma, granulosa cell sarcoma and malignant lymphoma.

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