Abstract
1) Twenty-two cases bearing various tumors associated with erythrocytosis have been reported in Japan. Through analysis of 457 cases with various tumors at the Keio University Hospital, the incidence of erythrocytosis is estimated 2.2∼4.4% in renal carcinoma; 1.9∼3.8% in hepatoma; lower than 1% in uterine myoma, various brain tumors and gastric carcinoma.
2) The first case of a 38-year-old male having meningioma associated with erythrocytosis was reported. Erythropoietin (Ep) activity estimated by polycythemic mouse bioassay in the pre-operative serum and the tumor extract was elevated, suggesting that this tumor was “Ep producing tumor”. The estimation of Ep in 3 cases with gastric carcinoma possibly associated with erythrocytosis failed to suggest that gastric carcinoma is a variety of “Ep producing tumor”.
3) In renal adenocarcinoma associated with erythrocytosis, Ep activity in the tumor extract and pre-operative serum was elevated and Ep inhibitor normally present in the kidney tissue disappeared in the tumor extract.
4) In uterine myoma associated with erythrocytosis, Ep activity was elevated in the pre-operative serum and tumor extract. The elevated activity in the latter, however, was different in quality from that of the renal carcinoma. Ep inhibitor seemed to be not important for production of erythrocytosis.
In conclusion, careful examination of the patients bearing various tumors may lead one to find more cases of “Ep producing tumor”. The Ep estimation in the tumor extract is the most important for the diagnosis of “Ep producing tumor”.
It is suggested that there are at least two different mechanisms in the production of erythrocytosis associated with various tumors.
