Cytomorphological and immunohistochemical features of renal and extrarenal rhabdoid tumors.

Background: Rhabdoid tumors are rare, highly lethal neoplasms characterized by alterations of SMARCB1 gene in chromosome 22, which occurs in infants and children. Fine needle aspiration (FNA) is an effective technique to diagnose this tumor when combined with Immunohistochemistry (IHC) and molecular genetics. In this study, we describe four cases of renal and extra-renal rhabdoid tumor of which three cases were diagnosed on FNA with IHC.
Materials and Methods: The study includes four children with renal and extrarenal rhabdoid tumor retrieved from cytology archives. FNA was done with cell block, IHC, and cytogenetics. The cytomorphology with ancillary studies were reviewed along with histopathology which was available in 3 out of 4 cases.
Results: All the four cases had similar cytomorphologic features comprising of large cells having vesicular nuclei which can be central or eccentric with prominent nucleoli and abundant pale cytoplasm. Few cells had intracytoplasmic hyaline inclusion. Cell block with IHC confirmed the diagnosis in three cases. One case in which cell block could not be made the diagnosis was confirmed on biopsy with IHC.
Conclusion: Rhabdoid tumors are uncommon but aggressive neoplasms with poor prognosis. Our study highlights that they can be diagnosed accurately on FNA cytomorphology when combined with IHC on cell block.
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