Leukemoid reaction in sarcomatoid renal cell carcinoma: a two-case report

Leukemoid reaction is defined as reactive leukocytosis exceeding 40 × 10⁹/l, with a significant increase in early neutrophil precursors, and can be a paraneoplastic manifestation of various malignant tumors. Leukemoid reaction is a sign for poor prognosis in solid tumors so is sarcomatoid renal cell carcinoma (SRCC) when compared to more differentiated histologies. Here, we are reporting two cases of leukemoid reaction after radical nephrectomy, both of which were diagnosed as SRCC pathologically. The operations were successful: no complications were observed and the patients were discharged in good condition. However, a few weeks later, the white blood cell (WBC) count gradually increased. Even though routine management was done immediately, the count was still elevating. A diagnosis of a leukemoid reaction was established and both of them died shortly thereafter. Due to the poor prognosis of most patients with malignant leukemoid reaction, leukemoid reaction may be a predictor of prognosis in patients with SRCC, but more data are needed.