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Heat-Damaged RBC Scan A Case of Intrahepatic Splenosis Alexander Tamm, MD, Martha Decker, MD, Michael Hoskinson, MD, Jonathan Abele, MD, and Vimal Patel, MD Abstract: Intrahepatic splenosis results from autotransplantation of splenic tissue within the liver, usually after splenic trauma or splenectomy. We present a case of a 43-year-old male patient with an incidental liver lesion discovered on abdominal ultrasound. The diagnosis of intrahepatic splenosis was considered after CT and MRI before being definitively made with 99mTc-labeled heat-damaged RBC scintigraphy. The case report illustrates the imaging characteristics of this rare location of abdominal splenosis. Key Words: splenosis, heat-damaged RBC scintigraphy, MRI (Clin Nucl Med 2015;40: 453–454)

Received for publication October 10, 2014; revision accepted November 20, 2014. From the Department of Radiology and Diagnostic Imaging, University of Alberta, Edmonton, Alberta, Canada. Author contributions: A.T. and M.D. were primarily responsible for article preparation and submission. A.T. and V.P. were the radiology resident and radiologist responsible for reporting the imaging. M.H. and J.A. were nuclear medicine physicians responsible for reporting the nuclear medicine scan. All authors contributed to the article reviewing and editing. Conflicts of interest and sources of funding: none declared. Reprints: Alexander Tamm, MD, WMC 2A2.41, University of Alberta, 8440 112th St, Edmonton, Alberta, Canada T6G 2B7. E-mail: [email protected]. Copyright © 2015 Wolters Kluwer Health, Inc. All rights reserved. ISSN: 0363-9762/15/4005–0453

REFERENCES 1. Li H, Snow-Lisy D, Klein EA. Hepatic splenosis diagnosed after inappropriate metastatic evaluation in patient with low-risk prostate cancer. Urology. 2012;79: e73–e74. 2. Grande M, Lapecorella M, Ianora AA, et al. Intrahepatic and widely distributed intraabdominal splenosis: multidetector CT, US and scintigraphic findings. Intern Emerg Med. 2008;3:265–267. 3. Fremont RD, Rice TW. Splenosis: a review. South Med J. 2007;100:589–593. 4. Tsitouridis I, Michaelides M, Sotiriadis C, et al. CT and MRI of intraperitoneal splenosis. Diagn Interv Radiol. 2010;16:145–149. 5. Lake ST, Johnson PT, Kawamoto S, et al. CT of splenosis: patterns and pitfalls. AJR Am J Roentgenol. 2012;199:W686–W693. 6. Gunes I, Yilmazlar T, Sarikaya I, et al. Scintigraphic detection of splenosis: superiority of tomographic selective spleen scintigraphy. Clin Radiol. 1994;49:115–117. 7. Hagman TF, Winer-Muram HT, Meyer CA, et al. Intrathoracic splenosis: superiority of technetium Tc 99m heat-damaged RBC imaging. Chest. 2001;120: 2097–2098. 8. Ishibashi M, Tanabe Y, Miyoshi H, et al. Intrathoracic splenosis: evaluation by superparamagnetic iron oxide-enhanced magnetic resonance imaging and radionuclide scintigraphy. Jpn J Radiol. 2009;27:371–374.

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Clinical Nuclear Medicine • Volume 40, Number 5, May 2015

FIGURE 1. A 43-year-old man with a history of traumatic splenectomy was hospitalized with necrotizing bacterial pneumonia and underwent an abdominal ultrasound (US) for right upper abdominal pain. This revealed a 2.8-cm homogenous hypoechoic lesion with nonspecific internal vascularity in hepatic segment 3 (A, transverse Doppler; B, sagittal). A multiphase CT scan showed the lesion to be well defined and slightly hypodense to the liver (C). After contrast administration, the lesion was hypodense to the liver during the arterial phase and hyperdense during the portal venous phase (D, arterial; E, portal venous). The suspicion of an intrahepatic splenule was raised, and further specific imaging was performed in lieu of biopsy to avoid hemorrhage. MRI at 1.5 T, with sequences taken before and after administration of gadolinium, revealed the lesion to be hypointense to the parenchyma on T1-weighted imaging (F, in phase; G, out of phase) and mildly hyperintense on T2-weighted imaging (H). No brisk arterial enhancement was present after contrast administration, but homogenous enhancement of the entire lesion was observed at 1 minute, with central washout and a residual rim of peripheral enhancement seen at 5 minutes (I and J, precontrast and postcontrast 3-dimensional VIBE). These findings are atypical of any common benign or malignant liver lesion. The patient went on to have 99mTc-labeled heat-damaged RBC scintigraphy. This revealed focal high-grade tracer uptake in the region of the liver corresponding to the lesion and confirmed the diagnosis of intrahepatic splenosis without the need for biopsy (K, planar image; L, transverse SPECT/CT). Although intrahepatic splenosis is usually benign, correct identification is essential because misinterpretation can have a significant impact on patient management. For example, there are reported cases of intrahepatic splenules being misdiagnosed as metastases1 or as hepatocellular carcinoma in the setting of cirrhosis.2 Percutaneous biopsies can lead to major hemorrhage due to high vascularity. Thus, a high degree of suspicion is needed on the part of clinicians and radiologists. Identifying intrahepatic splenules on US, CT, and MRI remains challenging because imaging characteristics are nonspecific3 as demonstrated previously. On US, they appear as hypoechoic vascular soft tissue masses2; on CT, characterization may be difficult if they are small or located in regions of similar enhancement.2 The splenules appear similar to normal splenic tissue on MRI; a rim of low signal intensity on T1 and T2 may be present and represents a thin surrounding layer of fatty or fibrous tissue.4 99mTc-labeled heat-damaged RBC scanning is widely accepted as the criterion standard test for detecting splenic tissue5 and is superior to 99mTc SC.6,7 Superparamagnetic iron oxide–enhanced MRI has not been compared directly to heat-damaged RBC scintigraphy and is considered complimentary.8

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Heat-damaged RBC scan: a case of intrahepatic splenosis.

Intrahepatic splenosis results from autotransplantation of splenic tissue within the liver, usually after splenic trauma or splenectomy. We present a ...
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