Acute Presentations of Splenic Diseases

Infection

Leukemia and lymphoma

Portal hypertension

Acute splenic sequestration in sickle cell anemia

Lymphoproliferative diseases

Collagenosis

Langerhans cell histiocytosis

Storage disorders

Congestive heart failure

Sarcoidosis

Fig. 17.1

Splenomegaly—US—Sagittal view of the left flank in a 7-year-old girl with acute leukemia. Massive homogeneous enlargement of the spleen measuring about 16 cm on its sagittal length

One of the most common noninfectious causes of splenomegaly is portal hypertension (see Chaps. 8 and 15) in relation with chronic hepatic disease and cirrhosis. The associated hepatic features will be demonstrated by US, color Doppler, and elastography as required. Sometimes, the splenomegaly will be the initial finding leading to the discovery of the portal hypertension.

Sickle cell disease may lead to acute splenic sequestration and splenomegaly due to trapping of large amount of blood. Hypovolemic shock can ensue. The diagnosis is based on clinical findings and imaging is rarely performed. Whenever performed, US may show heterogeneity of the splenic parenchyma and patency of splenic vessels on Doppler evaluation [6, 7].

Infiltration of the spleen secondary to malignant hematological diseases (leukemia and lymphoma—see also Chap. 27) is another classical cause of splenomegaly. The infiltration may be diffuse or nodular (Fig. 17.2a). The nodules usually appear hypoechoic and multiple. CT or preferably Pet-CT may demonstrate the extent of the disease and other organs involvement as well as adenomegaly (Fig. 17.2b). Noteworthy, leukemia and lymphoma may also lead to splenic infarcts and splenic rupture (see below) [1].

Fig. 17.2

Splenic involvement by lymphoma. (a) US—sagittal view of the left upper abdomen (13-year-old boy). The spleen, at its margin, appears nodular and hypoechoic (arrows). (b) CE-CT confirms the nodular involvement of the spleen and demonstrates multiple enlarged lymph nodes in the epigastric area. (c) PET scan demonstrates the whole body extension of the disease with multiple locations within the neck, chest, abdomen, and inguinoscrotal areas

Many other diseases may determine diffuse splenic involvement and multiple focal abnormalities (calcified or not). Most are infectious and related to bacterial, fungal, viral, and granulomatous infiltrate. Catch scratch fever (Fig. 17.3), TORCH, mycobacterium species, histoplasmosis, candidiasis, aspergillosis, and AIDS are potential agents. Previous history, clinical and biological data would help to differentiate between the potential causes. As for leukemia and lymphoma, US will detect the diffuse infiltration usually micronodular and patchy; whenever a systemic, more extensive disease is suspected, CT and/or MR imaging may be performed [1, 7, 8].

Fig. 17.3

Splenic involvement by Bartonellosis (Cat’s scratch disease) in a 2-year-old girl with axillary enlarged lymph nodes. Ultrasound—Transverse scan of the spleen showing hypoechoic ill-defined small irregular nodule (arrow)

Splenic tumors may be detected due to their sudden enlargement secondary to intra-tumoral hemorrhage. Lymphatic malformations, hemangioma, or angiosarcoma (Fig. 17.4) may typically bleed and determine acute “splenomegaly.” CT or MR imaging will be helpful in demonstrating an underlying tumor and its complication as well as the potential diagnosis [9].

Fig. 17.4

Epidermoid cyst of the spleen that has suddenly enlarged in a 4-year-old boy. (a) US—Transverse scan—displays a large (6 cm) cystic mass with central echogenic content potentially corresponding to hemorrhage. (b) CE-CT displays the well-limited mass with some dependent hyper-densities

Finally, the finding of splenomegaly may lead to the discovery of some systemic and metabolic diseases such as Langerhans cell histiocytosis or Gaucher disease [1].

17.3 Infarcts and Vascular Disorders

Splenic infarcts can be caused by various conditions such as hemoglobinopathies, torsion, collagen vascular diseases, splenic artery aneurysm, infection, or portal hypertension. It can also be caused by surgical inadvertent ligation of the splenic artery. The appearance of infarct depends on the time of the event and the extent of the infarcted area(s). In the acute phase, global infarction will determine edematous swelling of the spleen which will appear hypoechoic (Fig. 17.5a). The splenic parenchyma would appear more heterogeneous in case of more focused areas of infarcts such as in sickle cell disease. CT is the best imaging method to assess the degree of infarction (Fig. 17.5b). Infarcts will appear as non-enhancing areas. A subcapsular hematoma may be an associated finding.

Fig. 17.5

Post-operative status for neuroblastoma; peri-operative inadvertent ligation of the splenic artery (2-year-old boy). (a) US—sagittal of the spleen. It displays a peculiar hypoechoic pattern. (b) CE-CT—Completely absent enhancement of the spleen

Over time the infarcted area will tend to shrink with volume loss. Fibrosis or calcifications may develop [10–12].

Splenic artery aneurysm may develop secondary to trauma and pancreatitis. US with color Doppler is surely able to detect this vascular complication. Still, CT angiography should be performed whenever such anomaly is suspected in order to confirm the extent of traumatic lesions or the extent of pancreatic disease as well as to define the need of therapeutic embolization (see Chaps. 16 and 25) [13].

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