Delayed Enhancement Pattern in a Localized Fibrous Tumor of the Liver

Abstract

Moser T, Nogueira TS, Neuville A, et al. riginally described as pleural neoplasms, localized fibrous tumors are currently known to occur in numerous different locations, including the liver [1, 2]. Localized fibrous tumors are mesenchymal tumors composed of spindle cells interspersed with collagen bundles and containing a variable amount of vessels. Definitive diagnosis should be made only after immunohistochemistry, with CD34 being the most consistently positive marker [1–6]. Hepatic localized fibrous tumors are exceedingly rare, with all descriptions based on one or a few case reports that are not amenable to statistical analysis [3–5]. Fuksbrumer et al. [3] published the most extensive imaging description of hepatic localized fibrous tumors, to our knowledge. In their three-case series, hepatic localized fibrous tumor was characterized as a large solitary lesion appearing heterogeneous on sonography, CT, and MRI. We present a case of localized fibrous tumor occurring in the liver with radiologic– pathologic correlation and emphasis on the delayed enhancement of the tumor on CT and MRI. Case Report A 73-year-old woman was brought to the emergency service of our institution in hypoglycemic coma. She was neither diabetic nor under hypoglycemic medications. On admission, blood glucose level was 0.22 g/L (normal range, 0.70–1.1 g/L). Physical examination revealed a huge firm and rubbery mass in the right upper abdominal quadrant. Results of liver function tests were unremarkable. Blood insulin, C peptide, insulin-like growth factor 1, growth hormone, and cortisol were all within normal ranges. During hospitalization, glycemia was kept to normal through continuous IV infusion of 10% glucose solution and subcutaneous administration of glucagon. Abdominal sonography (Sonoline Elegra, Siemens) confirmed the presence of a huge mass in the right upper quadrant. It was hyperechoic to the liver parenchyma and contained numerous cystic foci. Helical CT images (ProSpeed SX Advantage, GE Healthcare) were obtained before (Fig. 1A) and 30 sec (Fig. 1B), 1 min (Fig. 1C), and five min (Fig. 1D) after IV contrast injection. These images showed a well-demarcated, hypodense lesion containing numerous prominent cystic areas. Portions of the lesion enhanced faintly during both the arterial (30 sec) and portal (1 min) phases. However, marked contrast enhancement was seen 5 min after injection. Cystic areas remained unchanged throughout the whole examination. The adjacent right liver lobe was displaced to the left mimicking an extrahepatic origin. However, a single tiny area of the tumor appeared in continuity with segment VII, which favored the hypothesis of a pedunculated hepatic mass. Preoperative workup also included MRI, with MR venography of the inferior vena cava on a 1.5-T scan (Magneton, Siemens). Spoiled gradient-echo T1-weighted sequences with fat suppression were obtained 30 sec, 1 min, and 8 min (Fig. 1E) after injection of gadolinium chelates. In addition, to rule out inferior cava vein obstruction, which would have influenced the surgical procedure, we obtained multiplanar images; these images reinforced the hypothesis of a pedunculated liver mass. Furthermore, the delayed enhancement pattern seen on CT was more conspicuously reproduced. The aforementioned clinical and imaging data suggested a mesenchymal hepatic tumor, and the hypothesis of a fibrosarcoma was raised.