[Clinical reasoning and decision making in practice. A 9-year-old boy with isolated splenomegaly].

Splenomegaly was discovered by chance in a 9-year-old boy who had no further complaints. Apart from splenomegaly and mild thrombocytopenia, no other pathological condition was found in the first instance. Ultrasound revealed a spleen with a median length of 16.7 cm. Blood tests remained stable and a bone marrow biopsy showed no pathology either. Doppler ultrasound of the splenic vessels was normal; screening for a coagulation disorder was not performed. A wait-and-see policy was instituted. Later, the patient developed haematemesis because ofoesophageal varices. It turned out that he had portal hypertension caused by thrombosis of the portal vein. The underlying cause was a heterozygous protein-C deficiency. Treatment consisted of anticoagulant therapy and a mesocaval shunt procedure. Splenomegaly is an atypical clinical manifestation in childhood. Coagulation disorders should be considered in children with splenomegaly.