Definition/General
Introduction:
Cervical rhabdomyosarcoma is a rare malignant tumor showing skeletal muscle differentiation
It primarily affects children and young adults, with embryonal subtype being most common in the genitourinary tract.
Origin:
Arises from primitive mesenchymal cells with potential for skeletal muscle differentiation
May develop de novo or from undifferentiated mesenchymal tissue in the cervical region.
Classification:
WHO Classification recognizes several subtypes: embryonal (most common in pediatric genitourinary), alveolar, pleomorphic, and sclerosing subtypes.
Epidemiology:
Extremely rare in cervical location
Peak incidence in children and adolescents (0-19 years)
Accounts for <1% of cervical malignancies
Slight female predominance.
Clinical Features
Presentation:
Rapidly growing cervical mass
Abnormal vaginal bleeding or discharge
Pelvic pain
Advanced cases may present with urinary or bowel obstruction.
Symptoms:
Vaginal bleeding or discharge (most common)
Pelvic pain or pressure
Rapidly enlarging mass
Urinary symptoms (frequency, retention)
Constipation.
Risk Factors:
Young age (children, adolescents)
Genetic syndromes (Li-Fraumeni, neurofibromatosis)
No clear environmental risk factors identified.
Screening:
No specific screening
Imaging shows heterogeneous soft tissue mass
MRI helpful for staging and surgical planning.
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Gross Description
Appearance:
Lobulated, soft, fleshy mass with gray-white to pink coloration
Areas of hemorrhage and necrosis common
May have polypoid appearance.
Characteristics:
Size variable (2-15 cm)
Soft, fleshy consistency
Gray-white to pink color
Lobulated surface
Hemorrhagic and necrotic areas frequent.
Size Location:
Can involve entire cervical region
May extend to vagina, parametrium, or uterine corpus
Often presents as large mass at diagnosis.
Multifocality:
Usually unifocal mass
May have satellite nodules
Extensive local invasion common
Metastatic deposits possible.
Microscopic Description
Histological Features:
Small round to spindle-shaped cells with varying degrees of skeletal muscle differentiation
Embryonal type shows primitive small blue cells with occasional rhabdomyoblasts.
Cellular Characteristics:
Primitive small round cells
Rhabdomyoblasts (strap cells) with eosinophilic cytoplasm
Cross-striations may be visible
High nuclear-to-cytoplasmic ratio.
Architectural Patterns:
Sheets of primitive cells
Myxoid stroma common in embryonal type
Alveolar pattern in alveolar subtype
Areas of differentiation variable.
Grading Criteria:
High-grade malignancy by definition
Subtype classification more important than grading
Embryonal type has better prognosis than alveolar.
Immunohistochemistry
Positive Markers:
Desmin positive
Myogenin positive (nuclear staining)
MyoD1 positive (nuclear staining)
Muscle-specific actin (MSA) positive.
Negative Markers:
Cytokeratin negative
S100 protein negative
CD99 variable
Smooth muscle actin typically negative.
Diagnostic Utility:
Myogenin and MyoD1 are specific for skeletal muscle differentiation
Desmin supports muscle differentiation
Essential for diagnosis.
Molecular Subtypes:
Embryonal: no specific translocations
Alveolar: t(2;13) PAX3-FOXO1 or t(1;13) PAX7-FOXO1 translocations.
Molecular/Genetic
Genetic Mutations:
Embryonal: complex karyotype, loss of heterozygosity at 11p15
Alveolar: specific translocations PAX3-FOXO1 or PAX7-FOXO1.
Molecular Markers:
High Ki-67 proliferation index
p53 mutations in some cases
PAX-FOXO1 fusion proteins in alveolar subtype.
Prognostic Significance:
Prognosis depends on subtype, stage, and age
Embryonal type has better prognosis than alveolar
Complete resection important.
Therapeutic Targets:
Multimodal therapy: surgery, chemotherapy, radiation
Vincristine, actinomycin D, cyclophosphamide (VAC) regimen standard.
Differential Diagnosis
Similar Entities:
Other small round cell tumors (Ewing sarcoma, lymphoma)
Cervical leiomyosarcoma
Undifferentiated carcinoma
Embryonal carcinoma.
Distinguishing Features:
Rhabdomyosarcoma: myogenin+, MyoD1+
Ewing sarcoma: CD99+, FLI1+
Lymphoma: CD45+
Carcinoma: cytokeratin+.
Diagnostic Challenges:
Recognition of skeletal muscle differentiation
Distinction from other small round cell tumors
Subtype classification.
Rare Variants:
Pleomorphic rhabdomyosarcoma (adults)
Sclerosing rhabdomyosarcoma
Spindle cell rhabdomyosarcoma.
Sample Pathology Report
Template Format
Sample Pathology Report
Complete Report: This is an example of how the final pathology report should be structured for this condition.
Specimen Information
[specimen type], measuring [size] cm in greatest dimension
Diagnosis
[diagnosis name]
Classification
Classification: [classification system] [grade/type]
Histological Features
Shows [architectural pattern] with [nuclear features] and [mitotic activity]
Size and Extent
Size: [X] cm, extent: [local/regional/metastatic]
Margins
Margins are [involved/uninvolved] with closest margin [X] mm
Lymphovascular Invasion
Lymphovascular invasion: [present/absent]
Lymph Node Status
Lymph nodes: [X] positive out of [X] examined
Special Studies
IHC: [marker]: [result]
Molecular: [test]: [result]
[other study]: [result]
Prognostic Factors
Prognostic factors: [list factors]
Final Diagnosis
Final diagnosis: [complete diagnosis]