Rhabdomyoma pathophysiology
Jump to navigation
Jump to search
|
Rhabdomyoma Microchapters |
|
Diagnosis |
|---|
|
Treatment |
|
Case Studies |
|
Rhabdomyoma pathophysiology On the Web |
|
American Roentgen Ray Society Images of Rhabdomyoma pathophysiology |
|
Risk calculators and risk factors for Rhabdomyoma pathophysiology |
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Nima Nasiri, M.D.[2]
Overview
Rhabdomyoma is a benign tumor of striated muscle. Rhabdomyomas are rare and can be classified into cardiac type and extracardiac type. The most common primary benign pediatric tumor of the heart is cardiac rhabdomyoma which can be seen mainly in fetal life and children, the second most common primary benign cardiac tumor in children is fibroma. Most tumors regress spontaneously, prognosis depends on the location of tumor and size. Cardiac rhabdomyoma is strongly associated with tuberous sclerosis.
Pathophysiology
Pathogenesis
Pathogenesis of rhabdomyoma depends on the type and location of the tumor.
Cardiac Rhabdomyoma
- Cardiac rhabdomyoma is typically seen in cases of tuberous sclerosis and the pathogenesis involves mutations in the TSC1 and TSC2 genes.[1]
- Mutations in the TSC1 and TSC2 genes affect downstream molecular signalling pathways, primarily the mTOR pathway that leads to disrupted cellular growth, proliferation and motility.[2][3]
- Activation of mTOR pathway leads to increased translation and protein production by ribosomal protein S6 kinase beta-1 (p70S6K) and eukaryotic translation initiation factor 4E-binding protein 1 (4E-BP1), contributing to the abnormal cell growth and proliferation
- Cardiac rhabdomyoma is usually diagnosed during the second or third trimester on ultrasound, rhabdomyoma appears as round, homogeneous, hyperechogenic masses in the ventricles, and they sometimes appear as multiple foci in the ventricles and septal wall. Differential diagnosis between rhabdomyoma, fibroma or myxoma using ultrasonography for a single cardiac mass remains difficult. [4][5]
- Cells usually lose their ability to divide and undergo apoptosis via a ubiquitin-mediated pathway and regression of the hamartoma ensues.[6]
- Result can be complete or partial regression of hamartoma tumor.
Extracardiac Rhabdomyoma
- The pathogenesis of extracardiac rhabdomyoma is largely unknown, however, constitutive activation of the Hedgehog signalling (SHH pathway activation) and association with Gorlin’s syndrome have been implicated as the two key mechanisms leading to development of these soft tissue tumors.[7][8]
Location
- Approximately 90% of adult rhabdomyoma are found in head and neck.[9][10]
- Adult rhabdomyoma 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.
- Genital rhabdomyoma most often involves the vagina or vulva.
- Location of cardiac rhabdomyoma determines the clinical presentation, it usually is multi foci and involves the myocardium of both ventricles and/or the interventricular septum, but can be found in the atrium as well as endocardium.
Immunohistochemistry
- Immunohistological cell markers include:
- Muscle specific actin, phosphotungstic acid hematoxylin (PTAH), desmin, and myoglobin.[9]
- Dystrophin is shown to be expressed in the cell membranes.
Gross Pathology
- On gross pathology, round or polypoid mass in the region of the neck are characteristic findings of adult rhabdomyoma.
- Round or lobulated, well-circumscribed masses which can be up to 10 cm in diameter.[11]
- Isolated or multiple.
- Solid tan-white homogeneous consistency, often watery and glistening on their cut surface.
- Infrequently, calcification and hemorrhage.
Microscopic Pathology
- On microscopic histopathological analysis, characteristic findings of adult rhabdomyoma include:
- Polygonal cells with eosinophilic granular cytoplasm that is mixed with intracellular vacuolated cells.
- Rhabdomyomas are very well differentiated similarly to striated muscle cells which present markers such as actin, desmin, and myoglobin; dystrophin on their cell membranes. [12]
- Histopathologic findings of fetal rhabdomyoma include spindle-shaped cells with vacuolated clear cytoplasm due to loss of glycogen or granulated ones.
- On microscopic histopathological analysis, characteristic findings of genital rhabdomyoma include:
- Fibroblast cells among them mature striated cells.
- A matrix containing varying amounts of collagen and mucoid material
- On microscopic histopathological analysis, characteristic findings of cardiac rhabdomyoma include of classic "spider cells" muscle cells similar to embryonic myofibrils.[13]
- On microscopic histopathological findings of Rhabdomyomatous mesenchymal hamartoma (RMH) which is a rare congenital lesion of the dermis and soft tissues consisting of a disordered and varied collection of mature adipose tissue, skeletal muscle, adnexal elements, and nerve bundles. Rhabdomyomatous mesenchymal hamartoma has different names including striated muscle hamartoma, congenital midline hamartoma, and hamartoma of cutaneous adnexa and mesenchyme. Several published cases report the occurrence of RMH within the setting of other uncommon congenital abnormalities.[12]
References
- ↑ "Enzinger and Weiss's Soft Tissue Tumors - 6th Edition".
- ↑ Kotulska K, Larysz-Brysz M, Grajkowska W, Jóźwiak J, Włodarski P, Sahin M, Lewin-Kowalik J, Domańska-Pakieła D, Jóźwiak S (2009). "Cardiac rhabdomyomas in tuberous sclerosis complex show apoptosis regulation and mTOR pathway abnormalities". Pediatr. Dev. Pathol. 12 (2): 89–95. doi:10.2350/06-11-0191.1. PMID 17990907.
- ↑ Krueger DA, Northrup H (October 2013). "Tuberous sclerosis complex surveillance and management: recommendations of the 2012 International Tuberous Sclerosis Complex Consensus Conference". Pediatr. Neurol. 49 (4): 255–65. doi:10.1016/j.pediatrneurol.2013.08.002. PMID 24053983.
- ↑ Sharma N, Sharma S, Thiek JL, Ahanthem SS, Kalita A, Lynser D (2017). "Maternal and Fetal Tuberous Sclerosis: Do We Know Enough as an Obstetrician?". J Reprod Infertil. 18 (2 pages=257–260). PMC 5565905. PMID 28868251.
- ↑ Bejiqi R, Retkoceri R, Bejiqi H (April 2017). "Prenatally Diagnosis and Outcome of Fetuses with Cardiac Rhabdomyoma - Single Centre Experience". Open Access Maced J Med Sci. 5 (2): 193–196. doi:10.3889/oamjms.2017.040. PMC 5420773. PMID 28507627.
- ↑ Wu SS, Collins MH, de Chadarévian JP (2002). "Study of the regression process in cardiac rhabdomyomas". Pediatr. Dev. Pathol. 5 (1): 29–36. PMID 11815866.
- ↑ Hettmer S, Teot LA, Kozakewich H, Werger AM, Davies KJ, Fletcher CD, Grier HE, Rodriguez-Galindo C, Wagers AJ (March 2015). "Myogenic tumors in nevoid Basal cell carcinoma syndrome". J. Pediatr. Hematol. Oncol. 37 (2): 147–9. doi:10.1097/MPH.0000000000000115. PMC 4127382. PMID 24517962.
- ↑ de Trey LA, Schmid S, Huber GF (2013). "Multifocal adult rhabdomyoma of the head and neck manifestation in 7 locations and review of the literature". Case Rep Otolaryngol. 2013: 758416. doi:10.1155/2013/758416. PMC 3697226. PMID 23841004.
- ↑ 9.0 9.1 Bjørndal Sørensen K, Godballe C, Ostergaard B, Krogdahl A (March 2006). "Adult extracardiac rhabdomyoma: light and immunohistochemical studies of two cases in the parapharyngeal space". Head Neck. 28 (3): 275–9. doi:10.1002/hed.20358. PMID 16419079.
- ↑ Amelia Souza A, de Araújo VC, Passador Santos F, Ferreira Martinez E, de Menezes Filho JF, Soares de Araujo N, Soares AB (2013). "Intraoral adult rhabdomyoma: a case report". Case Rep Dent. 2013: 741548. doi:10.1155/2013/741548. PMC 3833031. PMID 24288631.
- ↑ Kassop D, Donovan MS, Cheezum MK, Nguyen BT, Gambill NB, Blankstein R, Villines TC (2014). "Cardiac Masses on Cardiac CT: A Review". Curr Cardiovasc Imaging Rep. 7: 9281. doi:10.1007/s12410-014-9281-1. PMC 4090749. PMID 25018846.
- ↑ 12.0 12.1 Rosenberg AS, Kirk J, Morgan MB (April 2002). "Rhabdomyomatous mesenchymal hamartoma: an unusual dermal entity with a report of two cases and a review of the literature". J. Cutan. Pathol. 29 (4): 238–43. PMID 12028157.
- ↑ Fenoglio JJ, MCAllister HA, Ferrans VJ (August 1976). "Cardiac rhabdomyoma: a clinicopathologic and electron microscopic study". Am. J. Cardiol. 38 (2): 241–51. PMID 952267.