The leading cause of splanchnic vein thrombosis is myeloproliferative neoplasms (MPN), which are diagnosed in half of BCS patients and one-third of EHPVO patients.13,17,20,21,25 Until the mid 1990s, the so-called occult MPN was diagnosed on the basis of spontaneous endogenous erythroid colonies (growth of erythroid colonies in the absence of exogenous erythropoietin),25 which allowed recognizition of MPN in the early stages. The gene discussed is EPO; the disease is myeloproliferative neoplasm.