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F-FDG PET/CT Imaging of Malignant Hepatic Solitary Fibrous Tumor Le Song, MD, Weifang Zhang, MD, and Yanyan Zhang, MD

Abstract: Solitary fibrous tumor of the liver was rarely documented. 18F-FDG PET/CT imaging of malignant hepatic solitary fibrous tumor in a 49-year-old male patient was reported. The multifocal hepatic lesions demonstrated avid FDG uptake. FDG PET/CT might be potentially useful in the differentiation of benign and malignant solitary fibrous tumor. Key Words: solitary fibrous tumor, liver, PET (Clin Nucl Med 2014;39: 662Y664)

Received for publication November 21, 2013; revision accepted February 12, 2014. From the Department of Nuclear Medicine, Peking University Third Hospital, Beijing, People’s Republic of China. Conflicts of interest and sources of funding: none declared. Reprints: Yanyan Zhang, MD, Department of Nuclear Medicine, Peking University Third Hospital, 49 North Hua Yuan Rd, Haidian District, Beijing 100191, People’s Republic of China. E-mail: [email protected]; [email protected]. Copyright * 2014 by Lippincott Williams & Wilkins ISSN: 0363-9762/14/3907Y0662

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REFERENCES 1. Sun K, Lu JJ, Teng XD, et al. Solitary fibrous tumor of the liver: a case report. World J Surg Oncol. 2011;9:37. 2. Durak MG, Sagol O, Tuna B, et al. Cystic solitary fibrous tumor of the liver: a case report. Turk Patoloji Derg. 2013;29:217Y220. 3. Korkolis DP, Apostolaki K, Aggeli C, et al. Solitary fibrous tumor of the liver expressing CD34 and vimentin: a case report. World J Gastroenterol. 2008;14: 6261Y6264. 4. Chithriki M, Jaibaji M, Vandermolen R. Solitary fibrous tumor of the liver with presenting symptoms of hypoglycemic coma. Am Surg. 2004;70:291Y293. 5. Jakob M, Schneider M, Hoeller I, et al. Malignant solitary fibrous tumor involving the liver. World J Gastroenterol. 2013;19:3354Y3357. 6. Chan G, Horton PJ, Thyssen S, et al. Malignant transformation of a solitary fibrous tumor of the liver and intractable hypoglycemia. J Hepatobiliary Pancreat Surg. 2007;14:595Y599. 7. Peng L, Liu Y, Ai Y, et al. Skull base metastases from a malignant solitary fibrous tumor of the liver. A case report and literature review. Diagn Pathol. 2011;6:127. 8. Kandpal H, Sharma R, Gupta SD, et al. Solitary fibrous tumour of the liver: a rare imaging diagnosis using MRI and diffusion-weighted imaging. Br J Radiol. 2008;81:e282Ye286. 9. Azadi J, Subhawong A, Durand DJ. F-18 FDG PET/CT and Tc-99m sulfur colloid SPECT imaging in the diagnosis and treatment of a case of dual solitary fibrous tumors of the retroperitoneum and pancreas. J Radiol Case Rep. 2012;6:32Y37. 10. Wakisaka N, Kondo S, Murono S, et al. A solitary fibrous tumor arising in the parapharyngeal space, with MRI and FDG-PET findings. Auris Nasus Larynx. 2009;36:367Y371. 11. Alexander M, Yang S, Yung R, et al. Diagnosis of benign solitary fibrous tumors by positron emission tomography. South Med J. 2004;97:1264Y1267. 12. Lococo F, Cafarotti S, Treglia G. Is 18F-FDG-PET/CT really able to differentiate between malignant and benign solitary fibrous tumor of the pleura? Clin Imaging. 2013;37:976. 13. Yan J, Ahl KL, Manning KA, et al. Radiology-Pathology Conference: 18F FDG PET-CT imaging of solitary fibrous tumor of the pleura. Clin Imaging. 2013;37:598Y601.

Clinical Nuclear Medicine

& Volume 39, Number 7, July 2014

Copyright © 2014 Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited.

Clinical Nuclear Medicine

& Volume 39, Number 7, July 2014

PET/CT Imaging of Malignant Hepatic Solitary Fibrous Tumor

FIGURE 1. A 49-year-old man presented with abdominal discomfort for 20 days. Multiple hepatic lesions were detected on ultrasonography. Hepatic metastases were suspected, and PET/CT with 18F-FDG was performed. The maximum intensity projection image (A) showed multiple hepatic lesions (arrows). The cystic lesion (B, arrowheads) in segment VII, measuring 7.6  5.0  4.8 cm, demonstrated ring-like FDG uptake with an SUVmax of 11.5. The solid mass (C, arrows) in segment IV, measuring 3.8  3.5  3.1 cm, showed avid uptake with an SUVmax of 11.3. Another small nodule (B, arrows) measuring 0.6  0.6 cm in segment I also demonstrated increased uptake with an SUVmax of 3.7. The activity in the colorectal region and mediastinum was considered to be physiologic uptake. The 2 larger hepatic lesions were resected and histologically diagnosed as malignant solitary fibrous tumor.

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Clinical Nuclear Medicine

Song et al

& Volume 39, Number 7, July 2014

FIGURE 2. Pathological images (hematoxylin-eosin, original magnification 100) showed spindle cells with interspersed collagen bundles and branching vessels. Immunohistochemical studies revealed strong positivity for vimentin, CD34, and Bcl-2. The nodule in segment I remained unchanged during the 3-month follow-up. Solitary fibrous tumor is a rare mesenchymal-originated neoplasm, which usually involves the pluera.1 Hepatic solitary fibrous tumor is extremely rare, with less than 45 cases reported in the literature.2 It mainly occurs in women (about 2:1), with a mean age of 50 years.3 Most patients are asymptomatic; some may complain of unspecific symptoms such as abdominal fullness, a palpable mass, hypoglycemia, and fatigue.4Y6 Although most solitary fibrous tumors are benign and solitary, 10% to 15% are malignant, even with skeletal metastasis.5Y7 Histologically, solitary fibrous tumor is composed of spindle cells and shows an architecture of alternating hypocellular and hypercellular areas separated by collagen bands and branching vessels. Immunohistochemical studies show strong positivity for vimentin and CD34. Solitary fibrous tumor of the liver is hypodense on CT and occasionally displays calcification, intratumoral hemorrhage, necrosis, and cystic change.8 At contrast-enhanced CT, hepatic solitary fibrous tumor shows delayed, progressive, and persistent enhancement. These imaging features are nonspecific, and CT has limited value in differentiating benign and malignant solitary fibrous tumor. Although FDG PET/CT has been widely accepted as a useful tool in preoperative characterization of many neoplasms, its clinical utility in solitary fibrous tumor was rarely documented. The reported 5 cases (2 arising from the pleura, 2 from the pancreas, and 1 from the parapharyngeal space) with mild FDG uptake were all benign solitary fibrous tumors.9Y13 The colorectal and mediastinal activity in our case were considered physiologic uptake because the corresponding CT images showed nothing abnormal, and so did the 3-month follow-up CT. Therefore, primary hepatic malignancy was first considered because the lesions showed avid FDG uptake, even the 0.6-cm small nodule. This preliminary diagnosis was confirmed by pathologic study as malignant hypercellular solitary fibrous tumor. Our case further supported the view that FDG PET/CT might be potentially useful in the differentiation of benign and malignant solitary fibrous tumor.

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* 2014 Lippincott Williams & Wilkins

Copyright © 2014 Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited.

CT imaging of malignant hepatic solitary fibrous tumor.

Solitary fibrous tumor of the liver was rarely documented. F-FDG PET/CT imaging of malignant hepatic solitary fibrous tumor in a 49-year-old male pati...
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