Sarcomatoid renal cell carcinoma arising in hemodialysis-associated acquired cystic kidney disease presenting with disseminated bone marrow infiltration.

A 51-year-old man with a 23-year history of hemodialysis-dependant end-stage renal failure presented with pyrexia, malaise, and progressive pancytopenia. Investigations revealed acquired cystic kidney disease, with one cyst being interpreted as showing evidence of recent hemorrhage, and a malignant sarcomatoid bone marrow infiltrate. The patient rapidly deteriorated and died. At autopsy a seminecrotic and cystic sarcomatoid renal cell carcinoma was identified, with metastases in the adrenals, bone marrow, liver, lungs, and abdominal lymph nodes. The case is reviewed with regard to epithelial membrane antigen- and cytokeratin-negative bone marrow immunohistology as well as the immunophenotype of acquired cystic kidney disease and that expected in renal carcinoma, with reference to the literature on acquired cystic kidney disease.