Rhabdomyosarcoma 1

Alternative Names

  • RMS1
  • Rhabdomyosarcoma, Embryonal, 1
  • RMSE1
  • Rhabdomyosarcoma Chromosomal Region
  • RMSCR
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WHO-ICD-10 version:2010

Neoplasms

Malignant neoplasms

OMIM Number

268210

Mode of Inheritance

Autosomal recessive

Gene Map Locus

11p15.5

Description

Rhabdomyosarcoma tumor is a cancerous tumor that originates in the soft tissues due to uncontrolled, fast growing of the rhabdomyoblasts (a primitive muscle cell). Therefore, rhabdomyoblasts will not differentiate into striated muscles. This tumor may appear in any part of the body, except the bones, since muscle cells are found over the whole body. However, the four locations that rhabdomyosarcoma where usually appears as a noticeable lump are the head and neck (35-40%), genitourinary tract (20%), extremities (15-20%), and trunk (10-15%). Rhabdomyosarcoma is the most common soft tissue tumor in children that accounts for 4-8% of all pediatric cancers. This tumor may metastasize to other body parts such as lungs, lymph nodes, and brain. Histologically, rhabdomyosarcoma is divided into two major types: embryonal and alveolar, but embryonal rhabdomyosarcoma accounts for the majority of the cases (80%). Embryonal rhabdomyosarcoma affects children under 15 years and the tumor is found mostly in head and neck, and genitourinary tract. The cancerous cells in the embryonal type have "embryo-like" appearance under the microscope. Generally, diagnosis is done by tumor biopsy test, blood and urine test, and radiological findings. Patients are treated surgically with the association of chemotherapy, radiation and/or supportive treatments.

Molecular Genetics

Studies have shown that patients with embryonal rhabdomyosarcoma usually have a loss in the genetic material from the chromosome 11p15 region which suggests the presence of a tumor suppressor gene in that region. This gene is identified in some studies as the Beckwith-Wiedemann region 1A (BWR1A) gene. In addition, tumor protein p53 (TP53) mutations and point mutations in N-ras and K-ras oncogenes have been detected in some cases.

Epidemiology in the Arab World

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Other Reports

Bahrain

Vaidya and Al-Arrayed (1985) reported an eight-year-old Bahraini boy who presented with a painless swelling under the left upper lid over two weeks' duration. The boy was the first reported case in 15 years retrospective studies of orbital tumors in Bahrain. The swelling was cystic to palpation located in the superotemporal quadrant of the left orbit with downward displacement of the eyeball. Excision biopsy was attempted, but the mass being situated posteriorly in the orbit could not be excised completely. Histopathology reported embryonal rhabdomyosarcoma showing diffusely infiltrating myxoid tissue composed of spindle, oval, round and bizarre giant cells with pleomorphic large hyperchromatic nuclei. The patient was referred to a specialized cancer center in Kuwait for radiotherapy and chemotherapy. In addition, the Vincristine-Actinomycin Cyclophosphamide (VAC) regime was started. The patient remained free from local recurrence for 20 months when he presented again with a mass in the left orbit and with a mobile enlarged lymph node in the left axilla. He went again to Kuwait where exenteration of the orbit was performed and a pedicle graft was fashioned to cover the bare area. Seven months later, he was found to have multiple nodular swellings under the graft which were excised and a regrafting was done. After four months, he developed a huge recurrence. He had a profuse bleeding from the tumor mass following a trivial trauma few months later. Chemotherapy was given, but the tumor went on increasing enormously spreading to the other side of the face and encroaching upon the nose. An attempt to excise the mass was made, but the patient, unfortunately, remained in coma following the surgery and died two weeks later.

[Vaidya SP, Al-Arrayed H. Orbital rhabdomyosarcoma in a Bahraini child report of a case and review of the literature. Bahrain Med Bull. 1985; 7(2):65-8.]

Egypt

El-Sherbiny et al. (2000) conducted a retrospective analysis to study the long-term outcome of children with bladder and/or prostate rhabdomyosarcoma observed over a period of 17 years. In 30 affected children (26 boys and four girls, mean age 5 years, range 15 days to 15 years) 23 had stage III and seven had stage II disease. The initial biopsy showed an embryonal variant in 27 and round-cell sarcoma in three patients. All patients received eight weekly doses of vincristine, actinomycin D and cyclophosphamide (VAC). Subsequent treatment depended upon the response to chemotherapy. Fourteen patients had a complete or partial response to chemotherapy (> 50% reduction in tumour size). Twelve patients in this group survived with no evidence of disease for 7 months to 10 years. Additional therapies were used in three patients, i.e. radical cystectomy in one and external irradiation in two. Sixteen patients had a minimal response to chemotherapy; in six, radical cystectomy was feasible and was followed by one year of chemotherapy. All patients were free of disease for 4-11 years.

Jordan

Al-Khateeb and Bataineh (2002) conducted a retrospective study of the clinicopathologic features of rhabdomyosarcoma of the oral and maxillofacial region in Jordanian patients treated between 1989 and 2000. Nine patients with rhabdomyosarcoma aged 4 to 17 years were found, with a male to female ratio of 2:1. Six (67%) bony sites and 7 (78%) soft tissue sites were involved. The extent of disease was locoregional in 8 (89%) cases, nodal in 3 (33%) cases, and distant metastatic in 2 (22%) cases. The Intergroup Rhabdomyosarcoma Study classification of clinical groups indicated the presence of 2 (22%) cases in stage II, 5 (56%) cases in stage III, and 2 (22%) cases in stage IV. The histopathologic types found were 6 (67%) embryonal, 2 (22%) alveolar, and 1 (11%) undifferentiated.

Oman

Bhushan et al. (1996) reported an 18-year old male who presented with a two months history of gradually increasing left sided painless scrotal swelling. There was no history of trauma or fever. Clinically, there was a non-tender mass occupying the left hemi-scrotum with a negative transillumination test, and there were no palpable inguinal lymph nodes and the right testis was normal. General examination and investigations were normal. A provisional diagnosis of epididymitis/orchitis was made. However, ultrasound scan revealed a large solid extra-testicular mass of mixed echogenecity with irregular hypoechoic area representing necrosis and the epididymis could not be seen as a whole. The mass was anteriorly pushing the testis, which had low level echoes on its posterior aspect. There was no hydrocele. Abdominal ultrasound (for liver, spleen, and retroperitoneal lymph nodes), chest X-ray and abdominal and pelvic CT scans were normal. According to the above findings, a neoplasm of the left para-testicular region with involvement of the testis was suspected, and a high inguinal radical orchidectomy was done revealing a large, pinkish-white, hard tumor with the testis on its top. Macroscopically, there were areas of necrosis on its cut surface and histopathology diagnosed it as embryonal rhabdomyosarcoma arising from and replacing the whole of the epididymis and infiltrating the testis with evidence of vascular and lymphatic access. However, the tumor markers were normal (CEA, HCG, alpha fetoprotein). The patient further received chemotherapy in the form of vincristine, adrenamycin, and cytoxan. One year later, there was no evidence of any metastasis on CT scans of the abdomen and pelvis.

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