A Rare Red Herring: Intrahepatic Splenosis Masquerading as Hepatocellular Carcinoma

Abstract

Splenosis is defined as viable splenic tissue that is autotransplanted into other compartments in the body. Intrahepatic splenosis is a rare diagnosis that can be difficult for clinicians to identify. The most common causes of splenosis include abdominal trauma and splenectomy. While most patients with intrahepatic splenosis are asymptomatic, in the presence of risk factors of hepatocellular carcinoma, it is paramount to rule out malignancy. In this report, we present a patient with imaging findings concerning for hepatocellular carcinoma, ultimately diagnosed with percutaneous biopsy and technetium-99m-tagged heat-damaged red blood cell scintigraphy-proven intrahepatic splenosis.

Keywords: hepatocellular carcinoma; intrahepatic splenosis; radiology; splenectomy.

Figure 1.

T1-weighted abdominal MRI demonstrating a signal-restricted arterial enhancing mass measuring 5.1 cm in liver segment 2 with delayed washout concerning for malignancy. The lesion is LI-RADS 4 in the setting of prior hepatitis C. (A) T1 axial imaging before contrast administration. (B) T1 axial imaging during the arterial phase. (C) T1 axial imaging demonstrating delayed contrast washout. LI-RADS, Liver Imaging Reporting and Data System; MRI, magnetic resonance imaging.

Figure 2.

T2-weighted coronal and axial MRI (A, C) with corresponding nuclear medicine SPECT/CT fusion coronal and axial imaging after technetium-99m-tagged heat-damaged RBC administration (B, D). Reticuloendothelial cells located in splenic tissue phagocytose abnormal blood cells. Heat-denatured radiolabeled Tc-99m RBCs are injected into the patient and exclusively phagocytosed by the splenic tissue. Imaging is performed under a gamma scan, which tracks the uptake of nuclear-labeled RBCs. Compared with spleen detection using technetium-99m sulfur colloid, scintigraphy with heat-denatured RBCs has a higher diagnostic value because of the lack of liver uptake and its superior specificity. Tc99m sulfur colloid is taken up by the liver because of a relatively smaller particle size; thus, an intrahepatic splenic nodule may be masked by liver uptake. CT, computed tomography; MRI, magnetic resonance imaging; RBC, red blood cell; SPECT, single-photon emission computed tomography.

Figure 3.

Ectopic spleen. Hematoxylin and eosin-stained standard histologic sections show splenic tissue mainly composed of red pulp attached to a large hepatic portal tract (A). CD8 immunohistochemical stain labels littoral and endothelial cells with partial histiocytic functions specific to the spleen (B). Reticulin special stain highlights sinusoids (C). CD34 immunohistochemical stain shows normal blood vessels. Asterisks mark bile ducts. Arrowheads mark sinusoids.