In all congenital hemopathies, the spleen traps the abnormal red blood cells and tries to eliminate them. This splenic overload will lead to splenomegaly, a classical finding in the early course of the disease. It may develop acutely, leading to the so-called “acute splenic sequestration crisis” (ASSC), usually seen in infants and young children. ASSC is characterized by sudden onset of anemia, massive splenomegaly, and abdominal pain. The clinical presentation is usually straightforward and no imaging is necessary.

The spleen may also be affected by successive episodes of infarction progressively leading to atrophy of the spleen and eventually to auto-splenectomy [3]. On US, the parenchyma of the infarcted spleen appears heterogeneous with alternating hypo- and hyperechoic areas. The atrophied spleen appears small with irregular contours and it may calcify (see Chap. 17).

Whenever US is inconclusive or contradicts clinical symptoms, a CE-CT can help to demonstrate the infarcted areas (Fig. 28.2) and vascular complications.

Sickle cell disease may induce episodes of vaso-occlusive crisis and hemolysis by sicklemic microvascular occlusion. These phenomena may affect any organ or vessel. Paralytic ileus or pseudoobstruction is a rare complication of sickle cell disease. Symptoms are non-specific: functional occlusion with distended bowel loops and vomiting. The treatment is medical and imaging is generally not necessary, beside a plain radiograph of the abdomen to exclude mechanical obstruction [4].

LCH is a systemic proliferative disorder characterized by clusters of Langerhans cells organized as granulomas. LCH is generally considered as a benign disease but chemotherapy is the main part of treatment. The most common manifestation of LCH is skeletal involvement. Extra-osseous disease is less frequent and indicates a more aggressive disease. Abdominal involvement corresponds to 40% of extra-osseous disease. In the abdomen LCH affects mainly the hepatobiliary and GI tract.

The liver itself is involved in 15–20% cases and this involvement is considered a feature of poor prognosis [5]. Children present with abdominal pain and rarely jaundice. Imaging may demonstrate the various stages of the involvement.