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Rhabdomyosarcoma

Rhabdomyosarcomas

Rhabdomyosarcoma is a rare, highly malignant soft tissue tumor that develops from cells of the striated muscle. It occurs most frequently in the head and neck and is also found in the genitourinary tract, extremities and retroperitoneum. The two most common forms are embryonal rhabdomyosarcoma and alveolar rhabdomyosarcoma.


Presentation

Systemic symptoms

Systemic manifestations include weight loss, stunted growth, lethargy and weakness of the affects child.

Specific symptoms

Specific signs and symptoms vary on the basis of the primary site if the tumor. Some common sites and their presenting signs include:

  • Eyes: Tumors behind or around the eyes or orbital cavity may present with symptoms such as bulging of the eyes called proptosis or disconjugate gaze [4], visual defects, swelling or puffiness around the eyes and sometimes pain.
  • Nasal or oral cavity: RMS in the nasal cavity may cause congestion or blockage, anosmia and bleeding. If it is present in the oral cavity it may cause pain or difficulty in swallowing. If the tumor extends from either cavity to the brain, neurological symptoms may start appearing.
  • Auditory canal: RMS in the ear or auditory canal may present with hearing loss, pain and swelling. A mass may or may not be palpable.
  • Parameningeal: Upper respiratory symptoms or pain [5].
  • Extremities: RMS in the muscles of the arms or legs may present with a solid lump which may be mistaken for a swelling due to injury. The mass may or may not be painful.
  • Urogenital tract: RMS is the urinary bladder or elsewhere in the urinogenital tract may present with symptoms such as incontinence, hesitancy and urgency in urination.
Inguinal Lymphadenopathy
  • Abstract A 21-year-old lady presented with a rapidly progressive vulvar swelling with inguinal lymphadenopathy for 7 months. Pathological evaluation revealed it as a case of rhabdomyosarcoma.[ncbi.nlm.nih.gov]
Foul Smelling Discharge
  • A 16-year-old adolescent presented with a proliferating growth and foul smelling discharge from her vagina, which, on biopsy was diagnosed as RMS. She received chemotherapy and radiation to the primary site.[ncbi.nlm.nih.gov]
Abdominal Mass
  • Here, we present an apt example of a young girl with large abdominal mass which was diagnosed as ovarian rhabdomyosarcoma (RMS). Besides, her excellent response to RMS regimen further reinforces the findings.[ncbi.nlm.nih.gov]
  • Clinical findings were consistent with a diagnosis of cardio-facio-cutaneous syndrome (CFC-s), and a huge abdominal mass was evident on computed tomography scan. A biopsy was performed, and embryonal rhabdomyosarcoma was diagnosed.[doi.org]
  • The diagnosis of hepatic cyst with RMS was supported by the long history of a stable abdominal mass and the histopathology findings.[journals.lww.com]
  • GU cancers cause abdominal pain, a palpable abdominal mass, difficulty urinating, and hematuria. Extremity cancers appear as firm, indiscrete masses anywhere on the arms or legs.[msdmanuals.com]

Workup

A complete workup of a patient suspected to have RMS includes a detailed history and physical examination.

Laboratory test

A number of tests are conducted to diagnose RMS. These may include:

  • Complete blood count (CBC)
  • Lumbar puncture
  • Biopsy of the mass
  • Biopsy of the bone marrow to check for metastasis 
  • Urinalysis to check for hematuria which may indicate urinary tract involvement
  • Liver function tests
  • Fluorescent in situ hybridization (FISH)
  • Polymerase chain reaction (PCR)

Imaging

Imaging helps us grade and stage the tumor, if present. Imaging studies include:

  • X-ray of the chest
  • X-ray of the head and neck
  • CT scan of the site if mass
  • CT scan of the chest or other areas to check for metastasis
  • MRI
  • Bone scan to check for metastasis

Test results

Imaging studies may reveal the exact location and size of the mass as well as metastasis, if any. Biopsy will confirm that it is RMS.
Presence of proteins such as myogenin and myoD1 in tumor cells are diagnostically valuable because these proteins are transcription factors that are normally present only in developing striated muscles and disappear once development is complete.

Treatment

In patients with localised disease, overall 5% survival rates have improved to more than 80% with the combined use of surgery, radiation therapy and chemotherapy. As shown in the Intergroup Rhabdomyosarcoma Study (IRS)-IV reported in 2001, 5 year survival rates increased from 25% in 1973 to 73% [6].

A link between rhabdomyosarcoma and tungsten alloy embedded in muscle (eg. bullet or missile fragments) has been shown by a study. However it should be noted that the tungsten alloy contains 6% of nickel which happens to be a carcinogen [7]. Alternate methods of using the alloy without harmful effects of nickel have been suggested.

Currently the treatment of choice is surgery with radiation therapy, provided that the tumor is at a surgically accessible site. This is followed by chemotherapy that acts to destroy any leftover cancer cells as well as to prevent recurrence and metastasis.
In a phase II trial of 87 patients having RMS who had suffered a first relapse or disease progression and whose disease progression was unfavourable, temsirolimus proved superior to bevacizumab [7] [9]. At 6 months, the response rate also favoured temsilorimus (47.4% vs. 27.5%). The rate of progressive disease was also better with temsilorimus (28% vs. 10%) [7] [9].

In certain subpopulations with preexisting renal abnormality that predispose them to nephrotoxicity, cyclophosphamide is often added (VAC protocol). The overall survival rate for this group is more than 90% [10].

Prognosis

Like all other malignant tumors, the prognosis of RMS depends upon the subtype, location and size or the cancer. Distant metastasis, although very rare, may be present which may negatively affect the prognosis.

If caught on early, and if given complete and appropriate treatment, a child suffering from RMS may lead a long relatively healthy life.

The incidence of anaplasia in patients with RMS may be higher than previously described and may be of prognostic significance in children with intermediate risk-RMS, as its presence appears to negatively affect prognosis [4].

Complications with respect to the disease itself include first and foremost metastasis to other organs. This way not only the primary site of the tumor will be diseased but failure or insufficiency of the organ to which metastasis has occurred will appear. Other such complications may arise due to the bulging mass as it may press the surrounding and underlying structures leading to their injury, ischemia and other damage.

Complications with respect to treatment of the cancer include the adverse effects of chemotherapy and radiation therapy. The tumor may be present in a site inaccessible for surgery, thus complicating the disease.

Etiology

The exact cause of a rhabdomyosarcoma is heretofore unknown. However some risk factors such as gene mutations may possibly play a role in its development. But even risk factors are usually absent in most children presenting with this disease. Studies reveal that some families have a tendency to develop this cancer but the exact carrying link has not yet been discovered.

Epidemiology

Incidence

Only around 350 cases of RMS are diagnosed every year in the United States in people below 21 years of age. It is estimated that only 4:1 million children aged 15 or less will develop this cancer annually.

Sex

Rhabdomyosarcoma is slightly more common in boys.

Age

Although it may arise at any age, RMS is common in people in their 1st and 2nd decade of life and most common in children aged 5 years or less.

Sex distribution
Age distribution

Pathophysiology

RMS can arise anywhere in the body where there is striated muscle but it is most commonly, around 40% of total cases, found in the head and neck muscles. The second most common area in both males and females is the urinogenital tract occurring about 25% of total cases. RMS may also arise from the upper or lower limbs in 20% of cases, making the extremities the third most common location.

Types

The most recent classification system, the International Classification of Rhabdomyosarcoma was created by the Intergroup Rhabdomyosarcoma Study [2]. This classification is based on the histologic subtype of RMS. According to it, 5 subtypes have been proposed. These are:

There are other subtypes as well, like pleomorphic rhabdomyosarcoma or sclerosing rhabdomyosarcoma, but they do not fit into this classification. Of all the subtypes, the 2 most common are embryonal and alveolar RMS. Patients older than 10 years with embryonal histology and all patients with alveolar histology have 5 year survival rates of less than 30% [3].

Embryonal rhabdomyosarcoma

This is the most common subtype and occurs more in younger children. Histologically, the tumor appears to resemble a 6-8 week embryo.

Alveolar rhabdomyosarcoma

The second most common subtype, alveolar RMS occur in 20% of patients with RMS. Histologically, the tumor appears to resemble a 10-12 week embryo. It is more common in older children.

Metastasis

Although RMS is a malignant tumor, it rarely exhibits distant metastasis. Only 1 out 5 children with RMS would show distant metastasis to the brain, liver or other such organs.

Prevention

There are no known set of precautions that may help combat this disease. But it can be assumed that prevention may be similar to that of other cancers. Avoiding exposure to harmful radiations, toxins, drugs and alcohol, particularly during pregnancy, may prevent the occurrence of this sarcoma.

Summary

Rhabdomyosarcoma (RMS) is a malignant tumor that arises from striated muscles. It is the most common soft tissue cancer found in children. According to Rubin, it is derived from primitive mesenchyme that retained its capacity of skeletal muscle differentiation [1].

Since striated muscles are present almost all over the body, a rhabdomyosarcoma may arise anywhere in muscles that are attached to the bone, because that is where (most) striated muscles are located. This means a RMS may arise from the head and neck, arms, legs, etc. however, RMS may often arise from regions not having a lot of striated muscles particularly the head and neck area.

Rhabdomyosarcoma makes up to 3% of all cancers occurring in children.

Patient Information

Rhabdomyosarcoma is a malignant tumor that has no cure and no known prevention. It arises from connective tissue or the striated muscle cells, most commonly in the head and neck region. It is a very rare cancer, occurring mostly in children only. General symptoms include weight loss, fatigue and sometimes the presence of a palpable mass. Other signs and symptoms vary on the basis of the site of the primary tumor. Treatment is based on the subtype, of which there are more than 7, and serves to increase life expectancy and quality. A combination of surgery, radiation therapy and chemotherapy is used to fight the spread of this cancer.

References

Article

  1. Rubin E, Farber EL, eds. Pathology. Vol 1. Philadelphia:. J B. Lippincott Company;1994: 1343-4.
  2. Newton WA, Gehan EA, Webber EL, et al. (September 1995). Classification of Rhabdomyosarcoma and Related Sarcomas. Pathological Aspects and Proposal for a new classification- an Intergroup Rhabdomyosarcoma Study. Cancer 76(6) 1073-85. 
  3. Anderson JR, Ruby E, Link M. Identification of a favourable subset of patients with metastatic Rhabdomyosarcoma: a report from the Intergroup Rhabdomyosarcoma Study Group. Proceedings of the American society of Clinical oncology. Alexandria VA: American Society of Clinical Oncology:1997;A1836:510a.
  4. Barr FG. Molecular genetics and pathogenesis of Rhabdomyosarcoma. J Pediatr Hematol Oncol. Nov-Dec 1997;19(6)4831-91
  5. Williamson D, Missiaglia E, de Rhynies A, Pierron G, Thuille B, Palenzuela G, et al. Fusion gene-negative alveolar Rhabdomyosarcoma is clinically and molecularly indistinguishable from embryonal Rhabdomyosarcoma. J Clin Oncol. May 1 2008;28(13)2151-8 
  6. Qualman S, Lynch J, Bridge J, Parham D, Teot L, Meyer W, et al. Prevalence and clinical impact of anaplasia in childhood Rhabdomyosarcoma: a report from the Soft tissue sarcoma Committee of the Children's Oncology Group. Cancer. Dec 2008;113:3242-3247
  7. Chris WM, Anderson JR, Meza JL. Intergroup Rhabdomyosarcoma Study-IV: results of patients with nonmetastatic disease. J Clin Oncol. June 15 2001; 19(12):3091-102 
  8. Kalinich JF, Emond CA, Dalton TK, Mog SR, Coleman GD, Kordell JE, Miller AC, McClain DE. Embedded Weapons- Grade Tungsten Alloy Shrapnel Rapidly Induces Metastatic High-Grade Rhabdomyosarcomas in F344 Rats. Environmental Health Perspectives 2005 113 (6): 729-734. 
  9. National Collaborating Centre for Cancer. Guidance on Cancer Services: improving outcomes for people with sarcoma. London (UK): National I statute of Health and Clinical Excellence (NICE): March 2006. 138p.
  10. Arndt CA, Nascimento AG, Schroeder G. Treatment of intermediate risk Rhabdomyosarcoma and undifferentiated sarcoma with alternating cycles of vincristine/doxorubicin/cyclophosphamide and etoposide/ifosfamide. Eur J Cancer. July 1998;34(8):1224-9

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Last updated: 2019-07-11 21:45