Masked polycythaemia vera in a patient with extrahepatic portal venous obstruction.

Myeloproliferative disorder (MPD) is an important cause of thrombosis of the hepatic and portal venous system. The diagnosis in many of these patients is missed as they have an atypical clinical presentation and may have a normal haematological profile at presentation. We report a 30-year-old patient with features of portal hypertension due to extrahepatic portal venous obstruction. She had a normal haemoglobin level and haematocrit at presentation, but the red cell mass was found to be elevated even in the presence of low serum iron levels. A diagnosis of polycythaemia vera as the underlying disease was made.