Carol Shields
BASICS
DESCRIPTION
• Rhabdomyosarcoma (RMS) is a highly malignant neoplasm that arises from pluripotential cells that demonstrate histopathologic features of striated muscle.
• This tumor can arise in soft tissues throughout the body.
• RMS is the most common primary malignant orbital tumor of childhood.
ALERT
Optional. None.
Geriatric Considerations
Optional field. None.
Pediatric Considerations
Optional field. Rhabdomyosarcoma is more common in the pediatric age group.
Pregnancy Considerations
Optional field. Illicit drug use during pregnancy has been associated with an increased risk of rhabdomyosarcoma.
EPIDEMIOLOGY
Incidence
• 4.3 cases per 1 million children for all cases of RMS
• 5:3 male to female ratio for RMS of the orbit
• No racial predilection
Prevalence
• 350 new cases of systemic RMS per year
• Estimated 25–50 new cases of orbital RMS per year
RISK FACTORS
• Maternal use of marijuana during pregnancy has been found to cause 3-fold increased risk.
• Maternal use of cocaine during pregnancy is associated with 5-fold increased risk.
• Paternal use of marijuana, cocaine, or any recreational drug is associated with 2-fold increased risk.
Genetics
• Sporadic
• RMS has been associated with neurofibromatosis (NF) and Li–Fraumeni syndrome (LFS)
GENERAL PREVENTION
None
PATHOPHYSIOLOGY
In those cases with NF and LFS the p53 tumor suppressor gene has been identified.
ETIOLOGY
Unknown
COMMONLY ASSOCIATED CONDITIONS
None
DIAGNOSIS
HISTORY
Based on a large review of orbital RMS by Shields et al., the history reveals:
• Mean age at presentation of 10 years
• Acute and subacute painless proptosis in 30%
• Eyelid swelling in 21%
• Conjunctival injection in 9% and edema of the eyelids in 21%
• Symptoms present for a mean of 5 weeks
• Downward and outward displacement of the globe
• Pain and decreased vision are uncommon.
• History of trauma
PHYSICAL EXAM
Based on a comprehensive review of orbital RMS by Shields et al., the findings include the following:
• Orbital mass in 76%
• Conjunctival mass in 12%
• Proptosis in 79%
• Chemosis in 41%
• Eyelid edema in 21%
• Can mimic inflammation
DIAGNOSTIC TESTS & INTERPRETATION
Lab
Initial lab tests
• CBC count with differential to rule out leukemia, infection, and other simulating conditions
Follow-up & special considerations
• Complete systemic workup to evaluate for metastatic disease
• Chest radiograph to rule out lung metastasis, the most common site for RMS metastasis
Imaging
Initial approach
• MRI of orbits
• CT of orbits
– Round, oval, or irregular mass
– Well-circumscribed or diffuse
– Enhances with contrast
– May have cavities within it
– Usually in soft tissue
– Most common site is superonasal in the extraconal space
Follow-up & special considerations
• Patients with RMS need to be followed by a pediatric oncologist as well as an ocular oncologist or ophthalmologist familiar with the disease.
Diagnostic Procedures/Other
• Orbitotomy with intent to remove the malignancy completely intake within its pseudocapsule
• If the tumor is diffuse, enwrapping vital visual structures, then debulking of the tumor without damaging surrounding structures is advised.
Pathological Findings
• Small round blue cells with cross-striations within the cytoplasm representing 4 histological types:
– Pleomorphic—rarely involves the orbit
– Embryonal—most common in the orbit
– Alveolar—poorer prognosis
– Botryoid—often involves anterior portion of orbit, which appears as grape-like lesion beneath the conjunctiva
DIFFERENTIAL DIAGNOSIS
• Neuroblastoma
• Lymphangioma
• Hemangioma
• Dermoid cyst
• Inflammatory conditions
– Cellulitis
– Nonspecific inflammatory diseases
TREATMENT
MEDICATION
First Line
Chemotherapy is delivered by a pediatric oncologist. According to the Intergroup Rhabdomyosarcoma Study Group, the chemotherapy agents include vincristine, actinomycin-D, dactinomycin, cyclophosphomide, ifosfamide, and etoposide.
Second Line
Phase I/II trials include the use of chemotherapy agents such as doxorubicin (Adriamycin), melphalan, methotrexate, topotecan/irinotecan, taxol/docetaxel (Taxotere). These drugs are used alone or in combination with first-line agents.
ADDITIONAL TREATMENT
General Measures
• Refer to pediatric oncologist
• Staging—most orbital disease are group II or group III.
– Group I—tumor completely resected
– Group II—microscopic residual
– Group III—gross residual
– Group IV—metastasis
• According to Intergroup Rhabdomyosarcoma Study Group IV recommendations
– Group I is treated with chemotherapy for 32 weeks.
– Group II is treated with chemotherapy for 32 weeks and orbital radiotherapy (4,140 cGy).
– Group III is treated with chemotherapy for 52 weeks and orbital radiotherapy (5,040 cGy).
Issues for Referral
Any suspicious orbital lesion in a young patient should raise suspicion and prompt referral to an ocular oncologist.
Additional Therapies
See next item
COMPLEMENTARY & ALTERNATIVE THERAPIES
• Adjuvant chemotherapy
• Orbital radiotherapy
– Microscopic residual—4,000–4,500 cGy
– Gross residual—5,000–5,500 cGy
SURGERY/OTHER PROCEDURES
As indicated above, orbitotomy with excisional biopsy complete removal if possible is the first goal of therapy. Then further chemotherapy and radiotherapy depend on the staging.
IN-PATIENT CONSIDERATIONS
Initial Stabilization
Inpatient hospitalization might be necessary for chemotherapy.
Admission Criteria
Inpatient hospitalization might be necessary for chemotherapy.
IV Fluids
May be necessary for inpatient hydration
Nursing
Per floor routine for chemotherapy patients
Discharge Criteria
Once medically stable
ONGOING CARE
FOLLOW-UP RECOMMENDATIONS
• Every 2–3 months for the first year then every 6 months
– Repeat imaging every 6 months.
Patient Monitoring
• Watch for radiation side effects to eye and in field of treatment
• Based on a comprehensive review of orbital RMS by Shields et al., the findings include the following:
– Cataract in 55%
– Orbital hypoplasia in 24%
– Dry eye in 36%
– Chronic keratoconjunctivitis in 9%
– Retinopathy in 9%
– Recurrence can occur years after treatment.
– Late side effects of chemotherapy such as leukemia
DIET
No dietary restrictions
PATIENT EDUCATION
See Additional Readings.
PROGNOSIS
• Historically there was about 30% survival, but with adjuvant radiation/chemotherapy there is a 95% survival rate.
– Favorable prognosis in orbit because of early presentation and lack of lymphatic drainage
COMPLICATIONS
Side effects of radiation/chemotherapy
REFERENCES
1. Shields CL, Shields JA, Honavar SG, et al. The clinical spectrum of primary ophthalmic rhabdomyosarcoma. Ophthalmology 2001;108:2284–2292.
2. Shields JA, Shields CL, Scartozzi R. Survey of 1264 patients with orbital tumors and simulating lesions: The 2002 Montgomery lecture, part 1. Ophthalmology 2004;111(5):997–1008.
3. Hayes-Jordan A, Andrassy R. Rhabdomyosarcoma in children. Curr Opin Pediatr. 2009;21(3):373–378.
4. Shields JA, Shields CL. Rhabdomyosarcoma: Review for ophthalmologist. Surv Ophthalmol. 2003;48(1):39–57.
5. Karcioglu ZA, Hadjistilianou D, Rozans M, et al. Orbital rhabdomyosarcoma. Cancer Control. 2004;11(5):328–333.
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