Answer and Discussion of Quiz Set: N-032

2.    Deletion or mutation of hSNF5/SMARCB1/INI1 has not been described in which of the following tumors?

A.  Medulloblastoma

B.  Renal medullary carcinoma

C.  Epithelioid sarcoma

D.  Cribiform neuroepithelial tumor of the ventricle

E.  Malignant rhabdoid tumor

Answer and Discussion: The answer is (A). Many AT/RT contains small cell tumor component reminiscent of medulloblastoma, deletion of mutation of hSNF5/SMARCB1/INI1 can be found in these tumors and they are classified as AT/RT. Although deficient hSNF5/SMARCB1/INI1 was first believed to be unique to AT/RT and malignant rhabdoid tumors that are most commonly seen in pediatric age group, the spectrum of tumor with deficient hSNF5/SMARCB1/INI1 has been increasing and includes renal medullary carcinoma, collecting duct carcinoma of kidney, epithelioid sarcoma, synovial sarcoma, myoepithelial carcinoma, cribiform neuroepithelial tumor of the ventricle, and et cetera.

Further Reading:

• Agaimy A. The expanding family of SMARCB1(INI1)-deficient neoplasia: implications of phenotypic, biological, and molecular heterogeneity. Adv Anat Pathol. 2014 Nov;21(6):394-410.

• Chbani L, Guillou L, Terrier P, Decouvelaere AV, Grégoire F, Terrier-Lacombe MJ, Ranchère D, Robin YM, Collin F, Fréneaux P, Coindre JM. Epithelioid sarcoma: a clinicopathologic and immunohistochemical analysis of 106 cases from the French sarcoma group. Am J Clin Pathol. 2009 Feb;131(2):222-7.

• Hasselblatt M, Oyen F, Gesk S, Kordes U, Wrede B, Bergmann M, Schmid H, Frühwald MC, Schneppenheim R, Siebert R, Paulus W.Cribriform neuroepithelial tumor (CRINET): a nonrhabdoid ventricular tumor with INI1 loss and relatively favorable prognosis. J Neuropathol Exp Neurol. 2009 Dec;68(12):1249-55.