Expression of CD34 and β-Catenin in Malignant Rhabdoid Tumor of the Liver Mimicking Proximal-Type Epithelioid Sarcoma

Formal written informed consent was not required with a waiver by the appropriate institutional review board of Hartford Hospital and/or national research ethics committee. Loss of nuclear INI1 expression associated with deletions or mutations of the SMARCB1/INI1 gene at 22q11.2 is the characteristic hallmark of MRT.3,4 This genetic alteration, however, is also seen in other rare neoplasms, including proximaltype ES5 and SCUD hepatoblastoma.6 In particular, distinction between extrarenal MRT and proximal-type ES can be problematic due to morphologic similarities between the two entities; proximal-type ES also shows large epithelioid cells, vesicular nuclei with prominent nucleoli, and rhabdoid cytoplasmic inclusions. [...]we report a case of MRT of the liver with unusual immunophenotypic features mimicking proximal-type ES and SCUD hepatoblastoma.