AUTHOR AND EDITOR INFORMATION

Section 1 of 11  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• Multimedia
• References

INTRODUCTION

Section 2 of 11  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• Multimedia
• References

Background

Rhabdomyoma is a lesion of striated muscle. The 2 types of rhabdomyoma are neoplastic and hamartoma. The neoplastic variety is subclassified into adult, fetal, and genital types. Hamartomas are divided into cardiac rhabdomyoma and rhabdomyomatous mesenchymal hamartomas of the skin.

Rhabdomyoma is an exceedingly rare tumor. Some investigators believe that mature striated muscle is unlikely to develop tumorous tissue. Therefore, they believe that rhabdomyoma may arise from fetal rests.

Rhabdomyoma is diagnosed most often in men aged 25-40 years. However, the so-called fetal rhabdomyoma chiefly affects boys between birth and age 3 years.

Most rhabdomyomas involve the head and neck regions. The cardiac rhabdomyoma, which is believed to be a hamartoma, usually is diagnosed in the pediatric age group.

Pathophysiology

The adult rhabdomyoma is a rare tumor. Very few cases have been reported in the literature. This tumor usually presents as a round or polypoid mass in the region of the neck. The head and neck area harbors 90% of adult rhabdomyomas and should be considered in a differential diagnosis in this region (Bjorndal, 2006). Studies in immunohistochemistry confirm that the tumors are almost totally matured neoplasms of clonal origin. The mass is usually asymptomatic. However, the mass may compress or displace the tongue, or it may cause partial obstruction of the pharynx. Consequently, the patient may experience some hoarseness, difficulty breathing, and difficulty swallowing.

The histopathology of adult rhabdomyoma is characterized by the presence of well-differentiated large cells that resemble striated muscle cells. Cross-striation has been demonstrated by phosphotungstic acid hematoxylin (PTAH), muscle specific actin, desmin, and myoglobin while dystrophin is shown to be expressed in the cell membranes. The cells are deeply eosinophilic polygonal cells with small peripherally placed nuclei and occasional intracellular vacuoles. Adult rhabdomyoma usually is localized to the oropharynx, the larynx, and the muscles of the neck.

Fetal rhabdomyoma occurs most often in the subcutaneous tissues of the head and neck in children between birth and age 3 years. The histopathology of fetal rhabdomyoma reveals the presence of a mixture of spindle-shaped cells with indistinct cytoplasm and muscle fibers, which resemble striated muscle tissue observed in intrauterine development at 7-12 weeks. The fetal rhabdomyoma is usually found in the subcutaneous tissues of the head and neck.

Genital rhabdomyoma most often involves the vagina or vulva of young or middle-aged women. Most patients are asymptomatic. However, some patients have dyspareunia. The histopathology of genital rhabdomyoma reveals a mixture of fibroblastlike cells with clusters of mature cells containing distinct cross-striations and a matrix containing varying amounts of collagen and mucoid material. The genital rhabdomyoma usually presents as a polypoid or cystlike mass involving the vulva or vagina.

Cardiac rhabdomyoma is a hamartomatous lesion that occurs most often in the pediatric age group. Cardiac rhabdomyomas typically develop in utero and are often detected on prenatal ultrasound. It usually involves the myocardium of both ventricles and the interventricular septum. Cardiac rhabdomyoma is considered a hamartomatous proliferation frequently associated with tuberous sclerosis of the brain, sebaceous adenomas, and various hamartomatous lesions of the kidney and other organs. The association of tuberous sclerosis and cardiac rhabdomyoma is important and has usually been explained by strong clinical association. Molecular evidence of this association have now been identified as the TSC2 gene missense mutation (E36; 4672 G>A, 1558 E>K TSC2) (Jozwiak, 2005).

Rhabdomyomatous mesenchymal hamartoma is usually diagnosed in male and female newborns and infants. The histopathology of rhabdomyomatous mesenchymal hamartoma of the skin reveals that the lesions are located in the subcutis and contain poorly oriented or perpendicular bundles of well-differentiated skeletal muscle with islands of fat, fibrous tissue, and occasionally proliferating nerves.

Frequency

United States

Rhabdomyoma is an extremely rare tumor compared to other soft tissue tumors. Specifically, in the category of benign primary tumors of the heart, rhabdomyoma has a relative incidence of 5.8%.

International

Rhabdomyoma is rare. Exact data regarding its incidence within populations have not been cited. In the world literature, 14 cases of multifocal adult head and neck rhabdomyoma are reported.

Mortality/Morbidity

• The morbidity of rhabdomyoma depends on the type of lesion and its location. This is a benign tumor of striated muscle. Metastases have not been associated with this tumor.
• Cardiac rhabdomyomas are associated with the potential for flow abnormalities if they grow to sufficient size to restrict the left ventricular outflow tract. Although many are asymptomatic, some affected patients become symptomatic in the perinatal period. The types of clinical manifestations were illustrated in a report that included 15 children with cardiac rhabdomyoma (12 with tuberous sclerosis): the clinical presentation was heart failure or a cardiac murmur in 6 patients each, and arrhythmia in 3 (Webb, 1993). Based on clinical and molecular evidence, the diagnosis of fetal cardiac rhabdomyoma should lead to the careful evaluation of other fetal structures, including brain and renal parenchyma, to search for signs of tuberous sclerosis.

Race

Rhabdomyoma has been identified in all racial groups. No predilection for any particular racial group exists.

Sex

Adult rhabdomyoma has been diagnosed mostly in men. Some reports exist of cases in women. Fetal rhabdomyoma affects boys. Genital rhabdomyoma affects young and middle-aged women. Cardiac rhabdomyoma is observed in men and women. Rhabdomyomatous mesenchymal hamartoma of skin is observed in male and female newborns and infants.

Age

Adult rhabdomyoma occurs in older adults. These patients are usually older than 40 years. Fetal rhabdomyoma occurs between birth and age 3 years. Genital rhabdomyoma is observed in young and middle-aged women. Cardiac rhabdomyomas occur chiefly, but not exclusively, in the pediatric age group. Rhabdomyomatous mesenchymal hamartoma of the skin is observed in newborns and infants.

CLINICAL

Section 3 of 11  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• Multimedia
• References

History

The presenting history depends in part on the age and sex of the patient.

• Patients with adult rhabdomyoma give a history of having a mass in the region of the neck. They might experience some hoarseness, difficulty breathing, difficulty swallowing, or a combination.
• Patients with fetal rhabdomyoma may have a history of subcutaneous head and neck masses.
• Patients with genital rhabdomyoma are young or middle-aged women who might present with a complaint of dyspareunia.
• Patients with cardiac rhabdomyoma may present with a history of shortness of breath, sometimes associated with signs and symptoms suggestive of cerebral palsy (suggesting the possibility of associated tuberous sclerosis).

Physical

• The physical examination of a patient with adult rhabdomyoma probably reveals the presence of a round or polypoid mass in the region of the neck.
• Examination of the patient with fetal rhabdomyoma reveals subcutaneous masses in the head and neck regions.
• Examination of women with genital rhabdomyoma reveals vaginal masses.
• Patients with cardiac rhabdomyomas may present with heart murmurs. If tuberous sclerosis is associated, the patient displays cerebral palsy–type signs. Renal functions may be altered.

Causes

Rhabdomyoma probably represents a genetic variant of striated muscle development. Drugs or environmental factors have not been identified as causes of this neoplasm.

DIFFERENTIALS

Section 4 of 11  

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• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• Multimedia
• References

Other Problems to be Considered

Hibernoma
Reticulohistiocytoma
Tuberous sclerosis

WORKUP

Section 5 of 11  

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• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• Multimedia
• References

Lab Studies

• Order the usual laboratory studies, including CBC, hemoglobin/hematocrit, platelet count, and urinalysis.

Imaging Studies

• Perform routine radiographic studies, including radiographs of the chest and affected areas of the body.
• An MRI of the affected area might be useful.
• Occasionally, a CT scan, particularly of the chest in cases of cardiac rhabdomyoma, might be of value.

Other Tests

• When rhabdomyoma is suspected, a biopsy of the lesion is indicated. Needle biopsies can reveal sufficient information to make a histopathologic diagnosis.

Procedures

• Any masses, such as those found in the head and neck of patients with adult rhabdomyoma, should have biopsies performed to establish a diagnosis.
• • Make a small incision directly over the mass, and remove a small amount of tumor tissue. Close the wound in the usual manner.
  • A needle biopsy can be performed using a Tru-Cut needle. A small stab wound is made directly over the mass. The needle is introduced into the tumor, then it is withdrawn with a small amount of tumor tissue attached. Subsequently, a dressing is applied to the wound.

Histologic Findings

The histopathologic findings from patients with adult rhabdomyoma are characterized by the presence of well-differentiated large cells, which resemble striated muscle cells. The cells are deeply eosinophilic polygonal cells with small, peripherally placed nuclei and occasional intracellular vacuoles.

Fetal rhabdomyoma is identifiable by the presence of a mixture of spindle-shaped cells with indistinct cytoplasm and muscle fibers, which resemble striated muscle tissue seen in intrauterine development at 7-12 weeks.

Genital rhabdomyoma is made up of a mixture of fibroblastlike cells with clusters of mature cells containing distinct cross-striations and a matrix containing varying amounts of collagen and mucoid material.

Cardiac rhabdomyoma consists of cells that closely resemble embryonic cardiac muscle cells.

The histopathology of rhabdomyomatous mesenchymal hamartoma of the skin reveals that the lesions contain poorly oriented or perpendicular bundles of well-differentiated skeletal muscle with islands of fat, fibrous tissue, and occasionally proliferating nerves.

Staging

• Benign tumors can be staged as follows:
• • Stage 1, latent - Remains static or heals spontaneously
  • Stage 2, active - Progressive growth but limited by natural barriers
  • Stage 3, aggressive - Progressive growth not limited by natural barriers
• Grading, where G = grade; T = site; M = metastasis
• • G0 = benign
  • T0 = intracapsular
  • T1 = extracapsular, intracompartmental
  • M0 = none
• Staging
  • Benign stage 1, latent = G0, T0, M0
  • Benign stage 2, active = G0, T0, M0
  • Benign stage 3, aggressive = G0, T1, M0

TREATMENT

Section 6 of 11  

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• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• Multimedia
• References

Medical Care

Patients with adult rhabdomyoma may experience progressive difficulties in breathing and swallowing. In such instances, nasal oxygen may help patients with breathing difficulties. In circumstances in which swallowing is extremely difficult, supplemental intravenous fluids may be administered until surgery is performed. Patients with cardiac rhabdomyomas should be under the care of a cardiologist.

Surgical Care

• Patients with adult rhabdomyoma should have surgical resection of head and neck lesions, especially those lesions that compress or displace the tongue and those that may protrude and partially obstruct the pharynx or larynx.
• Fetal rhabdomyomas are usually located in the subcutaneous tissues. In most instances, they can be excised from various parts of the body without much difficulty.
• Local excision is the treatment of choice for genital rhabdomyomas.
• Open heart surgery may be necessary for the treatment of cardiac rhabdomyomas.

Consultations

• Patients with adult rhabdomyomas should be cared for in consultation with ear, nose, and throat (ENT) specialists.
• Patients with genital rhabdomyoma should be cared for in consultation with gynecologists and urologists.
• Patients with cardiac rhabdomyomas should be cared for by cardiologists and cardiothoracic surgeons.

Diet

Patients with adult rhabdomyoma and problems related to swallowing may need to be placed on a liquid diet.

Activity

Patients with adult rhabdomyoma who are experiencing breathing difficulties should restrict their activities until appropriate treatment can be undertaken. Patients with cardiac rhabdomyoma also must restrict their activities.

MEDICATION

Section 7 of 11  

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• Workup
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• Follow-up
• Miscellaneous
• Multimedia
• References

The goals of pharmacotherapy are to reduce morbidity and to prevent complications.

Drug Category: Analgesics

Generally, the usual pain medications (eg, aspirin with codeine, acetaminophen with codeine) may be used to relieve pain. Many patients with rhabdomyomas are asymptomatic; these patients rarely require strong pain medication.

FOLLOW-UP

Section 8 of 11  

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• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• Multimedia
• References

Further Inpatient Care

• Patients with adult rhabdomyomas may experience breathing difficulties. These patients may need nasal oxygen. If airway obstruction is diagnosed, surgical intervention should be considered.
• Patients with genital rhabdomyomas may require catheterization if they have symptoms of urinary tract obstruction.
• Patients with advanced cardiac rhabdomyomas should be placed in a cardiac care unit.

Further Outpatient Care

• Patients who have had surgical resection of their rhabdomyomas should have routine postoperative care (eg, dressing changes and suture removal when indicated).

In/Out Patient Meds

• Acetaminophen and codeine or oxycodone and acetaminophen may be used to control postoperative pain. Oxycodone with acetaminophen (Percocet) can produce drug dependence of the morphine type. Accordingly, the potential for drug abuse exists.

Deterrence/Prevention

• No measures can be used to prevent the occurrence of rhabdomyoma.

Complications

• Any surgical procedure can be complicated by infection.
• Patients with cardiac rhabdomyoma may develop congestive heart failure or arrhythmia.

Prognosis

• The prognosis for patients who have undergone surgery for the removal of rhabdomyomas varies from fair to good depending on the part of the body involved. Patients with cardiac rhabdomyomas have the highest risk.

Patient Education

• Patients with rhabdomyomas should be aware of the nature of their particular tumors and the type of surgical procedures available for treatment.

MISCELLANEOUS

Section 9 of 11  

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• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• Multimedia
• References

Medical/Legal Pitfalls

• Any surgical procedure has a risk of a malpractice claim. The patient must sign a detailed informed consent form before any procedure is performed.

Special Concerns

• Patients with genital rhabdomyomas who become pregnant need to be monitored closely. They may require a cesarean delivery.
• When fetal cardiac rhabdomyoma is diagnosed, careful evaluation of other fetal structures, including brain and renal parenchyma, should be performed to search for signs of tuberous sclerosis.

MULTIMEDIA

Section 10 of 11  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• Multimedia
• References

Media file 1:  Histopathology of adult rhabdomyoma. Microscopically, the adult rhabdomyoma contains deeply eosinophilic polygonal cells with peripherally placed nuclei. Cross-striations can be observed (X250).
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Media type:  Photo

Media file 2:  Atrial rhabdomyoma as seen on cardiac CT scan in a patient with tuberous sclerosis.
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Media type:  CT

Media file 3:  Nonobstructive ventricular rhabdomyomas in a patient with tuberous sclerosis.
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Media type:  CT

Media file 4:  Contrast-enhanced cardiac-gated T1-weighted MRI shows an enhancing left ventricular mass. At autopsy, this mass was found to be a cardiac rhabdomyoma.
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Media type:  MRI

REFERENCES

Section 11 of 11

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• Multimedia
• References

• Ashfaq R, Timmons CF. Rhabdomyomatous mesenchymal hamartoma of skin. Pediatr Pathol. Sep-Oct 1992;12(5):731-5. [Medline].
• Bastian BC, Brocker EB. Adult rhabdomyoma of the lip. Am J Dermatopathol. Feb 1998;20(1):61-4. [Medline].
• Bjorndal Sorensen K, Godballe C, Ostergaard B. Adult extracardiac rhabdomyoma: light and immunohistochemical studies of two cases in the parapharyngeal space. Head Neck. 2006;28(3):275-9.
• Bosi G, Lintermans JP, Pellegrino PA, et al. The natural history of cardiac rhabdomyoma with and without tuberous sclerosis. Acta Paediatr. Aug 1996;85(8):928-31. [Medline].
• Campanacci M. Bone and Soft Tissue Tumors. New York, NY:. Springer-Verlag;1986.
• Delides A, Petrides N, Banis K. Multifocal adult rhabdomyoma of the head and neck: a case report and literature review. Eur Arch Otorhinolaryngol. 2005;262(6):504-6.
• Iversen UM. Two cases of benign vaginal rhabdomyoma. Case reports. APMIS. Jul-Aug 1996;104(7-8):575-8. [Medline].
• Jozwiak S, Domanska-Pakiela D, Kwiatkowski DJ. Multiple cardiac rhabdomyomas as a sole symptom of tuberous sclerosis complex:case report with molecular confirmation. J Child Neurol. 2005;12:988-9.
• Kelekci S, Yazicioglu HF, Yilmaz B. Cardiac rhabdomyoma with tuberous sclerosis: a case report. J Reprod Med. 2005;50(7):550-2.
• Lapner PC, Chou S, Jimenez C. Perianal fetal rhabdomyoma: case report. Pediatr Surg Int. Sep 1997;12(7):544-7. [Medline].
• O''Callaghan FJ, Clarke AC, Joffe H, et al. Tuberous sclerosis complex and Wolff-Parkinson-White syndrome. Arch Dis Child. Feb 1998;78(2):159-62. [Medline].
• Tanda F, Rocca PC, Bosincu L. Rhabdomyoma of the tunica vaginalis of the testis: a histologic, immunohistochemical, and ultrastructural study. Mod Pathol. Jun 1997;10(6):608-11. [Medline].
• Webb DW, Thomas RD, Osborne JP. Cardiac rhabdomyomas and their association with tuberous sclerosis. Arch Dis Child. 1993;68(3):367-70. [Medline].

Article Last Updated: Nov 22, 2006