Atypical teratoid/rhabdoid tumour

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Atypical teratoid/rhabdoid tumour
Diagnosis in short

AT/RT. H&E stain.

LM cellular tumour with small round cells usu. with a prominent nucleolus, rhabdoid cells (eosinophilic granular cytoplasm + eccentric nucleus), mitoses. +/-necrosis (common)
LM DDx primitive neuroectodermal tumour (PNET), medulloblastoma, diffuse astrocytoma, choroid plexus carcinoma,embryonal carcinoma
IHC INI1 -ve, S-100 +ve, EMA +ve, SMA +ve
Site CNS - typically supratentorial

Clinical history usu. <3 years olds, occasionally adults
Prevalence uncommon - esp. in adults
Prognosis very poor

Atypical teratoid/rhabdoid tumour, abbreviated AT/RT, is malignant tumour usually found supratentorially.

It may be written atypical teratoid rhabdoid tumour (abbreviated ATRT) or atypical teratoid-rhabdoid tumour (abbreviated AT-RT).

It should not be confused with the extrarenal malignant rhabdoid tumour.

General

  • Usually supratentorial, occasionally in posterior fossa, case reports of spinal cord.
  • Individuals usually <3 years old, uncommon in adults.[1]
  • Prognosis very poor.[1]

Microscopic

Features:

  • Cellular.
  • Small round cells usu. with a prominent nucleolus.
  • Rhabdoid cells.
    • Cells with eosinophilic granular cytoplasm + eccentric nucleus.
  • Mitoses.
  • +/-Necrosis (common).

DDx:

Images

www:

IHC

  • BAF-47 -ve (AKA INI1, AKA SMARCB1 - the HGNC symbol[2]) - virtually diagnostic (4/4 cases[3]).
    • Endothelial cells +ve control.
  • S-100 +ve (4/4 cases[3]).
    • Few other brain tumours express it.
  • Vimentin +ve - perinuclear condensation (4/4 cases[3]).

Others:

  • GFAP +ve (focal - in tumour cells).
  • EMA +ve - patchy cytoplasmic (4/4 cases[3]).
  • Smooth muscle actin +ve.(4/4 cases[3]).
  • Cytokeratin +ve.[citation needed]

See also

References

  1. 1.0 1.1 Kanoto, M.; Toyoguchi, Y.; Hosoya, T.; Kuchiki, M.; Sugai, Y. (Jan 2014). "Radiological Image Features of the Atypical Teratoid/Rhabdoid Tumor in Adults: A Systematic Review.". Clin Neuroradiol. doi:10.1007/s00062-013-0282-2. PMID 24477665.
  2. Online 'Mendelian Inheritance in Man' (OMIM) 601607
  3. 3.0 3.1 3.2 3.3 3.4 Ertan, Y.; Sezak, M.; Turhan, T.; Kantar, M.; Erşahin, Y.; Mutluer, S.; Vergin, C.; Oniz, H. et al. (Jun 2009). "Atypical teratoid/rhabdoid tumor of the central nervous system: clinicopathologic and immunohistochemical features of four cases.". Childs Nerv Syst 25 (6): 707-11. doi:10.1007/s00381-009-0811-0. PMID 19212771.