Case Report

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American Journal of Emergency Medicine

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Elongated left lobe of the liver mimicking a subcapsular hematoma of the spleen on the focused assessment with sonography for trauma exam?,??

Abstract

The focused assessment with sonography for trauma examination has assumed the role of initial Screening examination for the presence or absence of hemoperitoneum in the patient with blunt abdominal trauma. Sonographic pitfalls associated with the examination have primarily been related to mistaking contained fluid collections with hemoperitoneum. We present a case in which an elongated left lobe of the liver was misdiagnosed as a splenic subcapsular hematoma. It is imperative that emergency physicians and trauma surgeons be familiar with this normal variant of the liver and its associated sonographic appearance on the perisplenic window in order to prevent nontherapeutic laparotomies or embolizations.

The Focused Assessment With Sonography for Trauma exam has assumed the role of initial screening examination for the presence or absence of hemoperitoneum in the patient with blunt abdominal trauma. The examination has its greatest utility in cases where the detection of hemoperitoneum would affect initial patient manage- ment since delays in operative management can increase morbidity and mortality [1]. Therefore it is essential that physicians performing the examination be aware of normal variants that could result in a false-positive diagnosis.

Since the goal of the abdominal portion of the FAST exam is the detection of hemoperitoneum, sonographic pitfalls have primarily been related to mistaking contained fluid collections for free intraperitoneal fluid collections. On the perisplenic window, fluid in structures adjacent to the spleen, such as the stomach and splenic flexure of the colon, can be mistaken for hemoperitoneum [2]. Elongation of the left hepatic lobe is a normal variant and can result in the liver wrapping around the spleen (Fig. 1). The liver may therefore be confused with a perisplenic fluid collection or hematoma due to the fact that the liver and spleen will have different echo textures [3-5]. The potential for misdiagnosing an elongated left hepatic lobe with a perisplenic hematoma has been remotely described in the radiology literature, but has not been described in the emergency medicine or trauma literature and is not discussed in any of the current textbooks on emergency and trauma ultrasound [3-5].

A 26-year-old female presents to the emergency department after being struck by a car while riding her bicycle. The patient was found to have stable vitals other than a mild tachycardia. On examination, she was found to have closed deformities of her left wrist and ankle. In

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addition, she had multiple bruises of her torso and was tender in the left upper quadrant. A FAST examination was performed in the trauma bay which revealed a crescent-shaped region adjacent to the spleen concerning for a subcapsular splenic hematoma (Fig. 2). Since the patient was normotensive, she was taken to the computed tomo- graphic (CT) scanner where the CT was read by the attending radiologist as being negative for acute traumatic injuries. The suspected splenic subcapsular hematoma was found to be an elongated left hepatic lobe. The patient was treated for her orthopedic injuries and had an uneventful hospitalization.

When the spleen sustains an injury, there are two possible outcomes. Either the capsule remains intact resulting in an intrapar- enchymal or subcapsular hematoma or the capsule may rupture resulting in hemoperitoneum. A diffuse heterogeneous echogenic pattern is the predominant pattern observed with splenic injuries but this pattern may be difficult to recognize in lower grade splenic injuries [6]. The associated subcapsular hematoma will appear as a crescent-shaped region between the spleen and diaphragm in the perisplenic window (Fig. 3). The subcapsular hematoma will be anechoic immediately after rupture but clotting will rapidly occur resulting in an echogenic appearance.

Fig. 1. CT scan in a patient with an elongated left lobe of the liver (L) adjacent to spleen (S).

0735-6757/(C) 2014

Fig. 2. Perisplenic window in which the elongated left lobe of the liver (arrowheads) is seen as a hypoechoic, crescent-shaped region cephalad to the spleen (S) mimicking a subcapsular hematoma.

Fig. 3. Splenic subcapsular hematoma.

Fig. 4. Perisplenic window with hepatic vein (arrowhead) and portal veins (arrows) noted within elongated left lobe (L).

Fig. 5. Color Doppler demonstrating flow within the spleen (S) and liver (L).

The size and shape of the left lobe of the liver is variable. When the left lobe of the liver is elongated, it will drape over the spleen (Fig. 1). Sonographically, the elongated left lobe of the liver will appear as a hypoechoic, crescent-shaped region between the diaphragm and the spleen mimicking a splenic subcapsular hematoma (Fig. 2).

Differentiating these two entities when performing the perisplenic window of the FAST exam can be challenging. In these cases, angling the transducer anterior in order to see if region is contiguous with the right lobe of the liver should be attempted first. If angling the transducer anterior does not aid in distinguishing between the two entities, then rotating the transducer 90? so that the scanning plane is axial may provide a better window to determine if the region is contiguous with the right lobe of the liver. Additionally, the region should be evaluated for the presence or absence of hepatic and/or portal veins (Fig. 4). Color Doppler may be used to aid in this diagnosis (Fig. 5). Further imaging will be required when Sonographic findings are inconclusive.

In conclusion, physicians performing the FAST exam need to be aware that an elongated left lobe of the liver will sonographically mimic the appearance of a splenic subcapsular hematoma on the perisplenic window. Additionally, physicians need to be aware of how to potentially differentiate between the two entities in order to minimize having a false-positive FAST exam.

Robert Jones, DO Matthew Tabbut, MD Diane Gramer, RVT

Department of Emergency Medicine MetroHealth Medical Center Cleveland, OH 44109, USA

http://dx.doi.org/10.1016/j.ajem.2013.12.050

References

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2. Nagdev A, J Racht, The “gastric fluid” sign: an unrecognized false-positive finding during focused assessment for trauma examinations. Am J Emerg Med, 2008;26(5): 630 e5-7.
3. Cholankeril JV, Zamora BO, Ketyer S. Left lobe of the liver draping around the spleen: a pitfall in computed tomography diagnosis of perisplenic hematoma. J Comput Tomogr 1984;8(3):261-7.
4. Li DK, et al. Pseudo perisplenic “fluid collections”: a clue to normal liver and spleen echogenic texture. J Ultrasound Med 1986;5(7):397-400.
5. Crivello MS, Peterson IM, Austin RM. Left lobe of the liver mimicking perisplenic collections. J Clin Ultrasound 1986;14(9):697-701.
6. Richards JR, et al. ultrasound detection of blunt splenic injury. Injury 2001;32(2): 95-103.