Differentiating Benign from Malignant Causes of Splenomegaly: Is Acoustic Radiation Force Impulse Elastography Helpful?

Abstract

Purpose: To evaluate the ability of acoustic radiation force impulse (ARFI) elastography in differentiating benign from malignant etiologies of splenomegaly based on differences in splenic stiffness.

Materials and methods: Between September 2020 and November 2022, we evaluated 40 patients with splenomegaly-defined by a splenic long axis greater than 13 cm and/or a short axis greater than 6 cm, without visible focal or infiltrative mass lesions-using abdominal ultrasound at our university hospital. Each patient also underwent a standardized ARFI elastographic assessment of the enlarged spleen, with data collected prospectively. We then retrospectively analyzed the cases with confirmed etiologies of splenomegaly from their final medical reports. Mean ARFI velocities (MAV) were compared across patients with splenomegaly due to malignant infiltration (MIS) from hematological malignancy, congestive splenomegaly (CS) due to portal or splenic vein congestion/occlusion, and immune-related splenomegaly (IRS) associated with systemic infectious or autoimmune diseases.

Results: Among the 40 patients with splenomegaly, 21 (52.5%) were diagnosed with malignant infiltrative splenomegaly (MIS), 11 (27.5%) with congestive splenomegaly (CS), and 8 (20%) with immune-related splenomegaly (IRS). The mean ARFI velocities (MAV) for the MIS, CS, and IRS groups were 3.25 ± 0.68 m/s, 3.52 ± 0.47 m/s, and 2.84 ± 0.92 m/s, respectively. No significant differences were observed in splenic stiffness (MAV) among these groups.

Conclusions: Differentiating between benign and malignant etiologies of splenomegaly based on stiffness differences observed in ARFI elastography is not feasible. Larger prospective studies are necessary to validate these findings.

Keywords: ARFI; point shear wave elastography; spleen; splenomegaly; ultrasound.

Figure 1

Benign congestive splenomegaly. A 52-year-old male patient with liver cirrhosis-related portal hypertension. (A) B-mode ultrasound image of the enlarged spleen with a length of 18.6 cm and a thickness of 8.0 cm; (B,C) two elastographic images of enlarged spleen showing shear wave velocities (Vs) of 3.69 and 3.20 m/s, respectively; (D) the final elastographic report of the enlarged spleen, showing a mean shear wave velocity (MW) of 3.10 m/s. Ort 1: location 1; Vs (m/s): velocity in meter per second; Tiefe (cm): depth in centimeter; MW: mean value (Mittelwert); Std-Abw.: standard deviation (Standard Abweichung); IQB: interquartile range (Interquartilbereich).

Figure 2

Malignant infiltrative splenomegaly. A 53-year-old male patient with myeloproliferative neoplasm (polycythemia vera). (A) B-mode ultrasound image of the enlarged spleen with a length of 19.8 cm and a thickness of 7.3 cm; (B,C) two elastographic images of enlarged spleen showing shear wave velocities (Vs) of 3.25 and 2.90 m/s, respectively; (D) the final elastographic report of the enlarged spleen, showing a mean shear wave velocity (MW) of 3.01 m/s. Ort 1: location 1; Vs (m/s): velocity in meter per second; Tiefe (cm): depth in centimeter; MW: mean value (Mittelwert); Std-Abw.: standard deviation (Standard Abweichung); IQB: interquartile range (Interquartilbereich).

Figure 3

Flow diagram of the study patients.

Figure 4

Comparison of mean ARFI velocities of spleen between benign and malignant groups (right) different subgroups (left). The mean is represented by an “X” in each box, and the median in different groups is represented by the horizontal line within each box. ARFI, acoustic radiation force impulse.