Rhabdomyosarcoma pathophysiology
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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 straited muscle cells.[1]
- 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%)
Pathogenesis
- The exact pathogenesis of rhabdomyosarcoma is unclear.[2]
- Distruption of skeletal muscle progenitor cell growth and related differentiation may cause rhabdomyosarcoma.[3]
- There is causal association between MET proto-oncogene and macrophage migration inhibitory factor (MIF).[4]
- It is thought that P53 is related to oncogenic transformation and tumor progression.
Genetics
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:[5]
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
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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
References
- ↑ Barr FG (1997). "Molecular genetics and pathogenesis of rhabdomyosarcoma". J Pediatr Hematol Oncol. 19 (6): 483–91. PMID 9407933.
- ↑ Taulli R, Scuoppo C, Bersani F, Accornero P, Forni PE, Miretti S; et al. (2006). "Validation of met as a therapeutic target in alveolar and embryonal rhabdomyosarcoma". Cancer Res. 66 (9): 4742–9. doi:10.1158/0008-5472.CAN-05-4292. PMID 16651427.
- ↑ Tarnowski M, Grymula K, Liu R, Tarnowska J, Drukala J, Ratajczak J; et al. (2010). "Macrophage migration inhibitory factor is secreted by rhabdomyosarcoma cells, modulates tumor metastasis by binding to CXCR4 and CXCR7 receptors and inhibits recruitment of cancer-associated fibroblasts". Mol Cancer Res. 8 (10): 1328–43. doi:10.1158/1541-7786.MCR-10-0288. PMC 2974061. PMID 20861157.
- ↑ Xu J, Timares L, Heilpern C, Weng Z, Li C, Xu H; et al. (2010). "Targeting wild-type and mutant p53 with small molecule CP-31398 blocks the growth of rhabdomyosarcoma by inducing reactive oxygen species-dependent apoptosis". Cancer Res. 70 (16): 6566–76. doi:10.1158/0008-5472.CAN-10-0942. PMC 2922473. PMID 20682800.
- ↑ "librepathology".