Rhabdoid tumor Cardiac rhabdoid tumor 2023-02-19T21:23:35Z A rare and aggressive neoplasms developing mainly in the kidney but also in cerebral and extra-cerebral tissues and rarely in the heart. Histologically, rhabdoid renal and extrarenal tumors share common characteristics. The cells are polygonal, with eccentric, vesicular nuclei and prominent nucleoli, eosinophilic cytoplasmic inclusions. The tumors have an infiltrative growth pattern, necrosis, and high proliferative index. The immunohistochemistry tools of investigation facilitate differential diagnosis by showing loss of INI-1 expression, usually accompanied by germline mutations of the SMARCB1 gene. When INI-1 is still expressed in the affected tissues, a rhabdoid tumor with SMARCA4 mutations should be considered.