Ultrasonographic atlas of splenic lesions

Abstract

Ultrasonography (US) is widely used for abdominal imaging. Its noninvasiveness, extensive range of application, and low cost make US a useful and valuable tool for the detection, diagnosis, and follow-up of splenic abnormalities. Concomitantly with the increasing frequency of imaging, more splenic lesions are being discovered and the requirements for the differential diagnosis are rising. In this pictorial essay, we introduce the representative US findings of many different splenic lesions, including normal sonographic findings, normal variants and congenital anomalies, infectious conditions, benign and malignant neoplasms, and non-neoplastic lesions. Knowledge of the US features of various splenic lesions will help narrow the differential diagnosis and guide clinical decision-making.

Keywords: Spleen; Splenic diseases; Splenic infarction; Splenic neoplasms; Ultrasonography.

Fig. 1.. A 49-year old man with a normal-appearing spleen on ultrasonography (US).

Longitudinal US of the normal spleen shows homogeneous and uniform parenchymal echogenicity, and a crescent shape with smooth outer convexity and nodulous inner margin.

Fig. 2.. A 3-year-old boy with an accessory spleen.

Longitudinal ultrasonography of the spleen shows an approximately 1.2-cm round to oval mass (arrows) with echogenicity identical to that of the spleen at the splenic hilum, suggesting an accessory spleen.

Fig. 3.. A 6-year-old girl with an intrapancreatic accessory spleen (IPAS).

Transverse ultrasonography of the pancreas shows a 1.3-cm round to oval echogenic mass (arrows) in the pancreas tail (arrowheads), with echogenicity that is identical to that of the splenic parenchyma, suggesting IPAS.

Fig. 4.. An 8-year-old girl with a wandering spleen.

A. Transverse ultrasonography of the lower abdomen shows a crescent-shaped homogeneous abdominal mass (arrows) suggesting that the spleen is in an unusual anatomical location, a condition known as "wandering spleen." In this patient, the ectopic spleen was enlarged and the parenchymal echogenicity was heterogeneous. B. Follow-up computed tomography scan of the same patient with abdominal pain shows torsion and ischemia of the wandering spleen (arrows).

Fig. 5.. A 60-year-old woman with pyogenic abscess of the spleen.

Longitudinal ultrasonography (US) of the spleen shows an oval heterogeneous hypoechoic lesion (arrow) with mild acoustic enhancement in the splenic hilum suggesting an abscess. Klebsiella pneumoniae was identified in US-guided aspiration.

Fig. 6.. A 65-year-old woman with pyogenic abscess of the spleen.

A. Longitudinal ultrasonography (US) of the spleen shows a poorly defined round anechoic cystic mass (arrows) with echogenic internal debris suggestive of an abscess. Salmonella group D was identified by US-guided aspiration. B. Axial contrast-enhanced computed tomography image shows a rim-enhancing multiseptated hypodense lesion (arrows) in the spleen.

Fig. 7.. A 35-year-old human immunodeficiency virus–positive man with miliary tuberculosis infection of the spleen.

A. Longitudinal ultrasonography (US) of the spleen shows multiple small (<1 cm) hypoechoic lesions in the splenic parenchyma. US-guided biopsy confirmed the presence of Mycobacterium tuberculosis. B. Axial contrast enhanced computed tomography image shows numerous, subcentimeter, hypodense nodular lesions throughout the spleen.

Fig. 8.. A 44-year-old woman with paragonimiasis.

A. Longitudinal ultrasonography (US) of the spleen shows an approximately 3.5-cm clustered multicystic lesion (arrows). US-guided biopsy confirmed eggs from Paragonimus westermani. B. Axial contrast-enhanced computed tomography image shows a lobulated hypodense splenic lesion with clustered multiple cysts (arrows). Two small peritoneal cystic lesions (arrowheads) and left pleural effusion were also observed. C. Microscopic image with hematoxylin and eosin staining (×400) shows the ovoid parasite eggs with a thick shell (arrows) in necrotic splenic tissue, morphologically consistent with P. westermani.

Fig. 9.. A 33-year-old woman with a splenic hemangioma.

A. Longitudinal ultrasonography (US) of the spleen shows an incidentally found, discrete, round, echogenic nodule (arrow). Color Doppler US (box) showed peripheral vascularity (arrowhead) of the nodule. B. Axial magnetic resonance imaging; a T2-weighted image shows multiple well-defined, round, T2 high-signal-intensity lesions suggestive of hemangiomas.

Fig. 10.. A 61-year-old woman with a splenic hemangioma.

A. Longitudinal ultrasonography of the spleen shows a lobulated cystic lesion (arrow) at the splenic inferior pole with an internal echogenic solid portion. B. Coronal contrast-enhanced computed tomography image shows a lobulated low-density lesion (arrow) in the splenic inferior pole.

Fig. 11.. A 70-year-old man with a splenic hamartoma.

A. Longitudinal ultrasonography of the spleen shows an approximately 5-cm, homogeneously isoechoic round mass (arrow) in the splenic upper pole. B. Axial contrast-enhanced computed tomography image shows a heterogeneously enhancing round mass (arrow) in the spleen, which was confirmed to be a hamartoma. C. Microscopic image with hematoxylin and eosin stain (×100) shows disorganized blood vessels of varying sizes intermingled with splenic red pulp.

Fig. 12.. A 74-year-old woman with splenic lymphangioma.

A. Transverse ultrasonography of the spleen shows an incidentally observed multiloculated cystic lesion measuring approximately 12 cm in the splenic upper pole. B. Coronal contrast-enhanced computed tomography image shows a multiloculated large cystic lesion with thin-wall calcification (arrow).

Fig. 13.. A 51-year-old woman with splenic sclerosing angiomatoid nodular transformation (SANT).

A. Longitudinal ultrasonography of the spleen shows an approximately 5 cm × 4 cm well-defined oval echogenic mass (arrow). B. Axial image of contrast-enhanced computed tomography shows the characteristic "spoke wheel" appearance (arrow) suggesting SANT.

Fig. 14.. A 56-year-old woman with diffuse large B-cell lymphoma (DLBCL).

A. Longitudinal ultrasonography (US) of the spleen shows numerous conglomerated hypoechoic nodules. B. Axial contrast-enhanced computed tomography image shows numerous hypodense nodules in the spleen. US-guided biopsy confirmed DLBCL involvement of the spleen.

Fig. 15.. A 6-year-old boy with systemic Epstein-Barr virus-positive T-cell lymphoma of childhood.

Longitudinal ultrasonography of the spleen shows a heterogeneously hypoechoic mass (arrow) with splenomegaly (11.5 cm).

Fig. 16.. A 48-year-old woman with rectal cancer with multiple metastases including splenic metastasis and peritoneal carcinomatosis.

A. Longitudinal ultrasonography of the spleen shows a round echogenic mass suggestive of metastasis. B. Axial contrast-enhanced computed tomography image shows multiple metastases to the liver, spleen, lymph nodes, and peritoneal carcinomatosis.

Fig. 17.. A 33-year-old man with splenomegaly and alcoholic hepatitis.

A-C. Longitudinal ultrasonography of the spleen (A), abdominal plain radiograph (B), and axial abdominal computed tomography image (C) shows splenomegaly (>21cm in length, arrows in B indicate enlarged splenic shadow).

Fig. 18.. An 83-year-old man with a splenic cyst.

Longitudinal ultrasonography of the spleen shows an approximately 4-cm well-defined round anechoic cystic lesion at the splenic upper pole.

Fig. 19.. A 41-year-old woman with splenic infarction and underlying liver cirrhosis and splenomegaly.

A. Longitudinal ultrasonography (US) of the spleen shows a well-defined hypoechoic area (arrows) in the enlarged spleen. B. Axial contrast-enhanced computed tomography image shows a wedge-shaped hypoenhancing area (arrows) in the enlarged spleen, which matched the US findings.

Fig. 20.. A 63-year-old man with Gamna-Gandy bodies in the spleen.

A. Longitudinal ultrasonography of the spleen shows numerous scattered tiny punctate hyperechoic foci (arrows). B. Axial non-enhanced computed tomography image shows multiple tiny calcifications (arrows) in the spleen.

Fig. 21.. A 3-year-old girl with splenic peliosis.

Longitudinal ultrasonography of the spleen shows splenomegaly and multiple poorly defined hypoechoic nodules (arrow).