Rhabdoid tumour

A rhabdoid tumor is a very aggressive form of tumor originally described as a variant of Wilms' tumor, which is primarily a kidney tumor that occurs mainly in children.

Malignant rhabdoid tumor (MRT) was first described as a variant of Wilms' tumor of the kidney in 1978.^[1] Malignant rhabdoid tumors (MRT) are a rare and highly malignant childhood neoplasm. Later rhabdoid tumors outside the kidney were reported in many tissues including the liver, soft tissue, and the central nervous system. Several cases of primary intracranial MRT have been reported since its recognition as a separate entity in 1978. The term "rhabdoid" was used due to its similarity with rhabdomyosarcoma under the light microscope. The exact pathogenesis of MRT is unknown.

The cerebellum is the most common location for primary intracerebral MRT (i.e., AT/RT). Biggs et al were first to report a primary intracranial MRT around 1987.^[2]

Although the cell of origin is not know, cytogenetic studies have suggested a common genetic basis for rhabdoid tumors regardless of location with abnormalities in chromosome 22 commonly occurring.

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Rhabdoid tumors in kidney and brain

Considerable debate has been focused on whether AT/RTs are the same as rhabdoid tumors of the kidney (i.e., just extra-renal MRTs (Maligant Rhaboid Tumors). The recent recognition that both CNS atypical teratoid/rhabdoid tumors (AT/RTs) and MRTs have deletions of the INI1 gene in chromosome 22 indicates that rhabdoid tumors of the kidney and brain are identical or closely related entities. Although, the CNS variant tends to have its mutations on Taxon 9 and MRTs elsewhere. This observation is not surprising because rhabdoid tumors at both locations possess similar histologic, clinical, and demographic features. Moreover, 10-15% of patients with MRTs have synchronous or metachronous brain tumors, many of which are second primary malignant rhabdoid tumors. This similarity excludes composite Rhabdoid tumors, which occur mainly in adults.

Prognosis

Regardless of location, all rhabdoid tumors are highly aggressive, have a poor prognosis, and tend to occur in children less than two years of age.

Genetics

It should be noted that there have been reported cases of a child having both atypical teratoid rhaboid tumors in the brain as well as rhabdoid tumors of the kidney. Weeks and associates reported on 111 renal rhabdoid cases of which 13.5% also had a central nervous system malignancy. It has been hypothesized that a germline INI mutation may predispose a child to these tumors. There have been some references in the literature alluding to a new diagnosis called rhabdoid predispostion syndrome related to the gene hSNF5/INI1.

Literature

• Donner LR, Wainwright LM, Zhang F, Biegel JA (2007). "Mutation of the INI1 gene in composite rhabdoid tumor of the endometrium". Hum. Pathol. 38 (6): 935–9. doi:10.1016/j.humpath.2006.12.003. PMID 17376508.

• Jeffrey S Dome, MD; D Ashley Hill, MD, (January 8, 2007). "Malignant Rhabdoid Tumor" (in English). eMedicine from WebMD.

• Perry A, Fuller CE, Judkins AR, Dehner LP, Biegel JA (2005). "INI1 expression is retained in composite rhabdoid tumors, including rhabdoid meningiomas". Mod. Pathol. 18 (7): 951–8. doi:10.1038/modpathol.3800375. PMID 15761491.

• Biegel JA, Fogelgren B, Wainwright LM, Zhou JY, Bevan H, Rorke LB (2000). "Germline INI1 mutation in a patient with a central nervous system atypical teratoid tumor and renal rhabdoid tumor". Genes Chromosomes Cancer 28 (1): 31–7. PMID 10738300.

• Huret J, Sevenet N (2000). "Rhabdoid predispostion syndrome" (in English). Atlas of Genetics and Cytogenetics in Oncology and Haematology (1:): 31-7.

• Weeks DA, Beckwith JB, Mierau GW, Luckey DW (1989). "Rhabdoid tumor of kidney. A report of 111 cases from the National Wilms' Tumor Study Pathology Center". Am. J. Surg. Pathol. 13 (6): 439–58. PMID 2543225.

References

1. ^ Beckwith JB, Palmer NF (1978). "Histopathology and prognosis of Wilms tumors: results from the First National Wilms' Tumor Study". Cancer 41 (5): 1937-48. PMID 206343.
2. ^ PJ Biggs; Garen PD, Powers JM, Garvin AJ (1987). "Malignant rhabdoid tumor of the central nervous system" (in English). Hum Pathol 1987 (18) ((4)): 332-337.