Leukemoid Reaction and Malignant Ascites in a Renal Carcinoma with Sarcomatoid Differentiation. Unusual Case Report and Literature Review

Renal cell carcinoma represents the 16th cause of death by cancer. It is one of the most frequent kidney tumors. This tumor could behave as a good mimicker, and is frequently associated with paraneoplastic syndromes. Metastases to peritoneum, mesentery or omentum are very rare. Sarcomatoid renal cell carcinoma is a high-grade undifferentiated component that can be found in any subtypes of renal cell carcinoma, and is associated with an aggressive behavior and a poor prognosis. We present the case of a 59-year-old male, diabetic patient, with nephron preserved left nephrectomy through lumbotomy seven years ago, upper pole renal carcinoma, admitted to the emergency department with indeterminate shock. He underwent a diagnostic laparoscopy and then open surgery due to findings where a greater omentum subtotal infarction. Omentum microscopic examination resulted in vaguely differentiated neoplasia, with sarcomatoid like cells, highly positive to CD10 inmunolabeling. Even though renal cell carcinomas have unusual clinical presentations, this case is unique because of the convergence of extremely rare manifestations such as the combination of malignant ascites, peritoneal carcinomatosis, and contralateral suprarenal gland metachronous metastases at the major omentum with paraneoplastic syndrome type leukemoid reaction; which have not been reported previously in literature.