Rhabdomyosarcoma pathophysiology

Rhabdomyosarcoma Microchapters
Home
Patient Information
Overview
Historical Perspective
Classification
Pathophysiology
Causes
Differentiating Rhabdomyosarcoma from other Diseases
Epidemiology and Demographics
Risk Factors
Screening
Natural History, Complications and Prognosis
Diagnosis
Diagnostic Study of Choice
Staging
History and Symptoms
Physical Examination
Laboratory Findings
Electrocardiogram
X Ray
CT
MRI
Ultrasound
Other Imaging Findings
Other Diagnostic Studies
Treatment
Medical Therapy
Surgery
Primary Prevention
Secondary Prevention
Cost-Effectiveness of Therapy
Future or Investigational Therapies
Case Studies
Case #1
Rhabdomyosarcoma pathophysiology On the Web
Most recent articles
Most cited articles
Review articles
CME Programs
Powerpoint slides
Images
American Roentgen Ray Society Images of Rhabdomyosarcoma pathophysiology All Images X-rays Echo & Ultrasound CT Images MRI
Ongoing Trials at Clinical Trials.gov
US National Guidelines Clearinghouse
NICE Guidance
FDA on Rhabdomyosarcoma pathophysiology
CDC on Rhabdomyosarcoma pathophysiology
Rhabdomyosarcoma pathophysiology in the news
Blogs on Rhabdomyosarcoma pathophysiology
Directions to Hospitals Treating Rhabdomyosarcoma
Risk calculators and risk factors for Rhabdomyosarcoma pathophysiology

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Shadan Mehraban, M.D.[2]

Overview

Rhabdomyosarcoma arises from the skeletal muscle cells. Development of alveolar rhabdomyosarcoma is result of specific genetic mutations. The pathogenesis of rhabdomyosarcoma include t(2;13) and t(1;13) chromosomal translocations. The microscopic pathology of rhabdomyosarcoma depends on the histological subtype.

Pathophysiology

Histology

• The origin of rhabdomyosarcoma is muscle cells.
• The presentation sites of rhabdomyosarcoma are:
  • Head and neck (28%)
  • Extremities (24%)
  • Genitourinary tract (18%)
  • Trunk (11%)
  • Orbit (7%)
  • Retroperitoneum (6%)
  • Other sites such as bladder, vagina, nasopharynx, and middle ear (3%)

Genetics

Alveolar rhabdomyosarcoma

Specific genetic abnormalities have been identified, that are specific for alveolar rhabdomyosarcomas. They include t(2;13) and t(1;13) chromosomal translocations resulting in PAX3-FKHR and PAX7-FKHR gene fusions.

Microscopic Pathology

Characteristic features on microscopic analysis are variable depending on the rhabdomyosarcoma subtype:

Alveolar Rhabdomyosarcoma

• Characterized by Alveolus-like pattern.
• Fibrous septae lined by tumor cells.
  • Cells may "fall-off" the septa, i.e. be detached/scattered in the alveolus-like space.
  • Space between fibrous septae may be filled with tumor, called solid variant of alveolar rhabdomyosarcoma.
• Rhabdomyoblasts: Essentially diagnostic cells with eccentric nucleus and moderate amount of intensely eosinophilic cytoplasm.
• Nuclear pleomorphism
• Mitoses

Alveolar Rhabdomyosarcoma- intermediate magnification

Alveolar Rhabdomyosarcoma - high magnification

Embryonal Rhabdomyosarcoma

• Randomly arranged small cells
• Myxoid matrix
• Strap cells: Tadpole like morphology
• Rhabdomyoblasts: Essentially diagnostic cells with eccentric nucleus and moderate amount of intensely eosinophilic cytoplasm

Botryoid Rhabdomyosarcoma

• Malignant cells in an abundant myxoid stroma.
• Non-proliferating layer deep to the surface called "Cambium layer".
• Cambium layer is defined as cellular region deep to epithelial component.

Spindlecell Rhabdomyosarcoma

• Vesicular growth pattern
• Spindle cells