Focal splenic lesions: US findings

Abstract

Ultrasound (US) imaging of the spleen was considered of little use in the past and was performed only to distinguish between cystic and solid lesions. However, in the last decade due to experience acquired and the introduction of second-generation contrast agents, this technique has been re-evaluated as contrast-enhanced US (CEUS) allows detection and characterization of most focal lesions of the spleen with a high sensitivity and a good specificity. Gray-scale US presents a low specificity in splenic infarctions with a high rate of false negative cases, whereas specificity reaches 100 %, if the examination is performed using US contrast agents. Gray-scale US can provide a correct diagnosis in simple cysts, whereas CEUS is useful when cystic lymphangioma is suspected. In the study of splenic lesions, the most important problem is to differentiate between angioma, hamartoma, lymphoma, and metastasis. CEUS reaches a good specificity in the differentiation of benign from malignant splenic lesions, as hypo-enhancement in the parenchymal phase is predictive of malignancy in 87 % of cases. In conclusion, Gray-scale US and particularly CEUS are at present widely indicated in the study of focal splenic lesions.Keywords Focal splenic lesion Á Splenic angioma/ hamartoma Á Splenic cysts Riassunto L'ecografia splenica è stata considerata nel passato poco utile ed indicata solo nella diagnosi differenziale tra lesioni cistiche e solide. Nell'ultimo decennio grazie alla maggior esperienza ed all'utilizzo dei mezzi di contrasto ecografici di II generazione (CEUS), questa metodica è stata rivalutata, in quanto consente di evidenziare e caratterizzare con elevata sensibilità e buona specificità la maggior parte delle lesioni focali della milza. Negli infarti splenici l'ecografia B-Mode ha una bassa specificità con elevata percentuale di falsi negativi, mentre questa risulta il 100 %, quanto l'esame è eseguito con i mezzi di contrasto ecografici. Nelle cisti semplici l'esame ecografico è sufficiente per porre una corretta diagnosi, mentre la CEUS può risultare utile nel sospetto di linfoangioma cistico. Il problema più importante a livello splenico è quello di definire con la maggior accuratezza possibile la diagnosi differenziale tra Angioma/Amartoma e Linfoma/Metastasi. La CEUS presenta nella lesioni spleniche una buona specificità nel differenziare una lesione benigna da una maligna, in quanto la presenza di ipoehnancement in fase parenchimale è predittiva nell'87 % dei casi di malignità. In conclusione l'ecografia B-Mode ed ancor più la CEUS trova al momento attuale ampie indicazioni nelle lesioni focali spleniche.

Primary spleen lymphoma visualized with contrast enhanced ultrasound – Case report

“…In the arterial phase malignant focal splenic lesions typically present heterogenous or homogenous hypo-enhancement. Reduced arterial enhancement in this case is probably due to neoangiogenesis, which creates a poor and slow flow [2,7].…”

“…The diagnostic value of CE-sonography in differentiating benign from malignant splenic focal lesions is based on different dynamics of uptake and washout of contrast agent during arterial and parenchymal phase [2]. There are essentially three enhancement patterns of splenic lesions [6,7]: 1) Lesions without enhancement at any phases.…”

“…It can be observed typically in splenic haemangiomas, hamartoma [7,8]. The great intensity of early arterial enhancement in benign splenic pathologies reflects hypervascularity caused by an increased arterial blood flow [2]. 3) Lesions with arterial enhancement and rapidly washout, a typical pattern for malignant lesions, such as metastases or lymphoma.…”

“…Splenic lymphoma can also appear on the grey scale as small, focal or miliary nodules (less than 5mm), multiple large nodular lesions and bulky solid masses [1,10]. Focal lesions are most often hypoechoic relative to normal splenic parenchyma (60-70%) [2,7]. Hiperechogenicity is not typical feature for splenic lymphoma and require histological confirmation.…”

“…More often the spleen is involved by lymphoma as a part of a systemic illness (30-40% of cases of systemic lymphoma, in both Hodgkin's and nonHodgkin's disease) with enlarged abdominal lymph nodes [1][2][3].…”